View Filing Data

Diluted weighted average number of outstanding units

434

424

422

Common Units

Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]

Net Income (Loss) Attributable to Common and Subordinated Units (Note 4)

$ 273

$ 148

$ (381)

Diluted net income (loss)

$ 273

$ 148

$ (381)

Basic weighted average number of outstanding

Basic weighted average number of outstanding

296

^[1]

216

214

Dilutive effect of Series A Preferred Units (in units)

$ 0.23

$ 0.24

$ 0.20

$ 0.26

$ 0.14

$ 0.26

$ 0.08

$ 0.21

$ 0.92

$ 0.69

$ (1.78)

Dilutive effect of performance units (in units)

Diluted weighted average number of outstanding units

297

216

214

Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]

0.23

0.24

0.20

0.26

0.14

0.26

0.08

0.19

$ 0.92

$ 0.69

$ (1.78)

Subordinated Units

Net Income (Loss) Attributable to Common and Subordinated Units (Note 4)

$ 127

$ 142

$ (371)

Diluted net income (loss)

$ 127

$ 142

$ (371)

Basic weighted average number of outstanding

Basic weighted average number of outstanding

137

208

Diluted weighted average number of outstanding units

0.00

^[2]

0.24

^[2]

0.20

^[2]

0.25

^[2]

0.14

0.26

0.08

0.20

$ 0.93

$ 0.68

$ (1.78)

137

208

Performance Units, Restricted Units, and Phantom Units

$ 0.00

^[2]

$ 0.24

^[2]

$ 0.20

^[2]

$ 0.25

^[2]

$ 0.14

$ 0.26

$ 0.08

$ 0.20

$ 0.93

$ 0.68

$ (1.78)

Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]

Dilutive effect of unit-based awards (in dollars per unit) (less than $.01)

$ 0.01

Phantom units

Dilutive effect of performance units (in units)

[1]	Basic weighted average number of outstanding common units for the year ended December 31, 2017 includes approximately one million time-based phantom units.
[2]	_____________________(1)See Note 5 for discussion of the conversion of the subordinated units.

Enable Midstream Partners, LP Partners' Equity - Schedule of Cash Distributions (Details) - USD ($)

1 Months Ended

Feb. 27, 2018

Feb. 20, 2018

Feb. 15, 2018

Feb. 09, 2018

Nov. 21, 2017

Nov. 14, 2017

Oct. 31, 2017

Aug. 29, 2017

Aug. 22, 2017

Aug. 14, 2017

Jul. 31, 2017

May 30, 2017

May 23, 2017

May 12, 2017

May 02, 2017

Feb. 28, 2017

Feb. 21, 2017

Feb. 15, 2017

Feb. 10, 2017

Nov. 22, 2016

Nov. 14, 2016

Nov. 01, 2016

Aug. 23, 2016

Aug. 16, 2016

Aug. 12, 2016

Aug. 02, 2016

May 13, 2016

May 06, 2016

Feb. 12, 2016

Feb. 02, 2016

Nov. 13, 2015

Nov. 03, 2015

Aug. 13, 2015

Aug. 03, 2015

May 15, 2015

May 05, 2015

Mar. 31, 2016

Distribution Made to Limited Partner [Line Items]

Nov. 14, 2017

Aug. 22, 2017

May 23, 2017

Feb. 21, 2017

Nov. 14, 2016

Aug. 16, 2016

May 06, 2016

Feb. 02, 2016

Nov. 03, 2015

Aug. 03, 2015

May 05, 2015

Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

Nov. 21, 2017

Aug. 29, 2017

May 30, 2017

Feb. 28, 2017

Nov. 22, 2016

Aug. 23, 2016

May 13, 2016

Feb. 12, 2016

Nov. 13, 2015

Aug. 13, 2015

May 15, 2015

Distribution Made to Limited Partner [Line Items]

Oct. 31, 2017

Jul. 31, 2017

May 02, 2017

Feb. 10, 2017

Nov. 01, 2016

Aug. 02, 2016

May 06, 2016

^[1]

Distribution Made to Limited Partner [Line Items]

Nov. 14, 2017

Aug. 14, 2017

May 12, 2017

Feb. 15, 2017

Nov. 14, 2016

Aug. 12, 2016

May 13, 2016

^[1]

Cash Distribution

$ 0.318

$ 0.316

$ 0.3125

Cash Distribution | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

$ 138,000,000

$ 137,000,000

$ 134,000,000

$ 132,000,000

Distribution Made to Limited Partner [Line Items]

$ 0.625

$ 0.2917

^[1]

Full quarter equivalent distribution declared (in dollars per unit)

$ 9,000,000

$ 4,000,000

^[1]

$ 0.625

Annualized distribution declared (in dollars per unit)

$ 2.50

Subsequent Event | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

Distribution Made to Limited Partner [Line Items]

Subsequent Event | Cash Distribution

^[2]

Feb. 09, 2018

Distribution Made to Limited Partner [Line Items]

Common unit cash distribution declared (in dollars per unit)

$ 0.318

Subsequent Event | Cash Distribution | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

Distribution Made to Limited Partner [Line Items]

Common unit cash distribution declared (in dollars per unit)

$ 0.625

Subsequent Event | Scenario, Forecast

Distribution Made to Limited Partner [Line Items]

^[3]

Feb. 20, 2018

Subsequent Event | Scenario, Forecast | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

^[3]

Feb. 27, 2018

Distribution Made to Limited Partner [Line Items]

^[2]

Feb. 09, 2018

Subsequent Event | Scenario, Forecast | Cash Distribution

^[2]

Feb. 15, 2018

Distribution Made to Limited Partner [Line Items]

^[3]

$ 0.318

Subsequent Event | Scenario, Forecast | Cash Distribution | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units

^[3]

$ 138,000,000

Distribution Made to Limited Partner [Line Items]

^[1]

$ 0.625

Investments in and Advances to Affiliates, at Fair Value [Roll Forward]

^[1]

$ 9,000,000

[1]	The prorated quarterly distribution for the Series A Preferred Units is for a partial period beginning on February 18, 2016, and ending on March 31, 2016, which equates to $0.625 per unit on a full-quarter basis or $2.50 per unit on an annualized basis.
[2]	The board of directors of Enable GP declared this $0.625 per Series A Preferred Unit cash distribution on February 9, 2018, which was paid on February 15, 2018 to Series A Preferred unitholders of record at the close of business on February 9, 2018.
[3]	The board of directors of Enable GP declared this $0.318 per common unit cash distribution on February 9, 2018, to be paid on February 27, 2018, to common unitholders of record at the close of business on February 20, 2018.

Enable Midstream Partners, LP Partners' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands					6 Months Ended	12 Months Ended
	Aug. 30, 2017	May 12, 2017	Nov. 29, 2016	Feb. 18, 2016	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Distribution Made to Limited Partner [Line Items]
Limited partners' capital account, required quarterly distribution period						60 days
Conversion ratio	100.00%
Limited partners capital account, minimum quarterly distribution, annualized						150.00%
Proceeds from issuance of Series A Preferred Units, net of issuance costs						$ 0	$ 362,000	$ 0
Number of common units in public offering			75,719
Limited Partner \| CenterPoint
Distribution Made to Limited Partner [Line Items]
Amount notes redeemed payable to wholly-owned subsidiary of CenterPoint Energy				$ 363,000
Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units
Distribution Made to Limited Partner [Line Items]
Annual percentage rate				10.00%
Liquidation preference (in dollars per share)				$ 25.00
Duration of cash distributions				5 years
Redemption price (in dollars per share)				$ 25.50
Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units \| LIBOR
Distribution Made to Limited Partner [Line Items]
Annual percentage rate				8.50%
Private Placement \| Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units
Distribution Made to Limited Partner [Line Items]
Issuance of Series A Preferred Units (in units)				14,520,000
Cash purchase price (in dollars per unit)				$ 25.00
Proceeds from issuance of Series A Preferred Units, net of issuance costs				$ 362,000
Expenses related to offering				$ 1,000
ATM Program
Distribution Made to Limited Partner [Line Items]
Expenses related to offering						$ 345
Aggregate offering price		$ 200,000
Number of common units in public offering						18,500,000,000
Proceeds received (net of underwriting discounts, structuring fees, and offering expenses)						$ 303
Commissions						$ 3
Public Offering
Distribution Made to Limited Partner [Line Items]
Number of common units in public offering			10,000,000
Public offering price (in dollars per share)			$ 14.00
Proceeds received (net of underwriting discounts, structuring fees, and offering expenses)			$ 137,000
Over-Allotment Option
Distribution Made to Limited Partner [Line Items]
Number of common units in public offering			1,500,000
Over-Allotment Option \| Affiliate of ArcLight Capital Partners, LLC
Distribution Made to Limited Partner [Line Items]
Number of common units in public offering			1,424,281
Subordinated Units \| Limited Partner \| OGE Energy
Distribution Made to Limited Partner [Line Items]
Units outstanding (in units)						68,150,514
Subordinated Units \| Limited Partner \| CenterPoint
Distribution Made to Limited Partner [Line Items]
Units outstanding (in units)						139,704,916
Distribution Subordination Period 1
Distribution Made to Limited Partner [Line Items]
Limited partners' capital account, minimum annualized quarterly distribution (in dollars per unit)						$ 1.15
Distribution Subordination Period 2
Distribution Made to Limited Partner [Line Items]
Limited partners' capital account, maximum annualized quarterly distribution (in dollars per unit)						$ 1.725
Maximum
Distribution Made to Limited Partner [Line Items]
Limited partners' capital account, incentive distribution rights, percentage					50.00%	50.00%
Minimum
Distribution Made to Limited Partner [Line Items]
Incentive distribution, distribution (in dollars per unit)					$ 0.330625	$ 0.330625
Subordinated Units
Distribution Made to Limited Partner [Line Items]
Units outstanding (in units)	207,855,430

Property, Plant and Equipment - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 12,079	$ 11,567
Accumulated depreciation	1,724	1,424
Property, plant and equipment, net	10,355	10,143
Depreciation expense	$ 335	311	$ 291
Gathering and Processing
Property, Plant and Equipment [Line Items]
Weighted Average Useful Lives (Years)	36 years
Property, plant and equipment, gross	$ 7,322	6,987
Accumulated depreciation	$ 865	681
Transportation and Storage
Property, Plant and Equipment [Line Items]
Weighted Average Useful Lives (Years)	34 years
Property, plant and equipment, gross	$ 4,538	4,498
Accumulated depreciation	859	743
Construction work-in-progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 219	$ 82

Intangible Assets, Net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 31	$ 27	$ 27
Expected amortization of intangible assets, 2018	45
Expected amortization of intangible assets, 2019	45
Expected amortization of intangible assets, 2020	45
Expected amortization of intangible assets, 2021	45
Expected amortization of intangible assets, 2022	45
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	581	405
Accumulated amortization	130	99
Net intangible assets	$ 451	$ 306
Weighted average useful life (in years)	13 years

Goodwill - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Goodwill - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013
Goodwill [Line Items]
Goodwill recognized	$ 0	$ 0	$ 1,068
Goodwill [Roll Forward]
Goodwill	0	0	1,068
Goodwill acquired	12		19
Goodwill impairment		(1,087)	(1,087)
Goodwill	12	0	0
Gathering and Processing
Goodwill [Line Items]
Goodwill recognized	0	0	489
Goodwill [Roll Forward]
Goodwill	0	0	489
Goodwill acquired	12		19
Goodwill impairment			(508)
Goodwill	12	0	0
Transportation and Storage
Goodwill [Line Items]
Goodwill recognized	0	0	579
Goodwill [Roll Forward]
Goodwill	0	0	579
Goodwill acquired	0		0
Goodwill impairment			(579)
Goodwill	$ 0	$ 0	$ 0
Enogex
Goodwill [Line Items]
Goodwill recognized				$ 438

Investment in Equity Method Affiliate - Narrative (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 29, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 12, 2015
Schedule of Equity Method Investments [Line Items]
Distributions from unconsolidated affiliates		$ 28	$ 28	$ 34
SESH
Schedule of Equity Method Investments [Line Items]
Limited partner ownership percentage interest	49.90%	50.00%	50.00%
Distributions from unconsolidated affiliates		$ 28	$ 28	34
SESH \| Shared Operations Service Agreements \| Equity Method Investee
Schedule of Equity Method Investments [Line Items]
Amount billed to SESH associated with service agreements		$ 17	$ 13	$ 12
SESH \| Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50.00%
Percentage distributions		50.00%
SESH \| CenterPoint \| Put Option
Schedule of Equity Method Investments [Line Items]
Fair value of common units					$ 1

Investment in Equity Method Affiliate - Schedule of Investments (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Balance beginning of period

$ 329

Distributions from unconsolidated affiliates

$ 28

$ 29

Balance end of period

324

329

Return of investment

(5)

(15)

(8)

Equity in Earnings of Equity Method Affiliates:

Investments in and Advances to Affiliates, at Fair Value [Roll Forward]

SESH

Balance beginning of period

329

Distributions from unconsolidated affiliates

(33)

(43)

(42)

Balance end of period

324

329

Return of investment

(5)

(15)

(8)

Distributions from Equity Method Affiliates:

SESH | Other Income (Expense)

(33)

(43)

(42)

Income Statement Data:

Revenues

113

115

Operating income

Net income

Investments in and Advances to Affiliates, at Fair Value [Roll Forward]

Equity in Earnings of Equity Method Affiliates:

SESH | Investments in Equity Method Affiliates

Investments in and Advances to Affiliates, at Fair Value [Roll Forward]

Balance beginning of period

329

344

348

Interest acquisition of SESH

Contributions to equity method affiliate

Equity in Earnings of Equity Method Affiliates:

^[1]

(33)

(43)

(42)

Balance end of period

324

329

344

Distributions from Equity Method Affiliates:

^[1]

$ (33)

$ (43)

$ (42)

[1]	Distributions from equity method affiliate includes a $28 million, $28 million and $34 million return on investment and a $5 million, $15 million and $8 million return of investment for the years ended December 31, 2017, 2016 and 2015, respectively.

Investment in Equity Method Affiliate - Financial Information of SESH (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Data:
Investment in SESH	$ 324	$ 329
SESH
Balance Sheet Data:
Current assets	32	31
Property, plant and equipment, net	1,093	1,110
Total assets	1,125	1,141
Current liabilities	14	18
Long-term debt	397	397
Members’ equity	714	726
Total liabilities and members’ equity	1,125	1,141
Investment in SESH	324	329
Less: Capitalized interest on investment in SESH	(1)	(1)
Add: Basis differential, net of amortization	34	35
The Partnership’s share of members’ equity	$ 357	$ 363

Debt - Schedule of Outstanding Debt (Details) - USD ($)

Dec. 31, 2017

Dec. 31, 2016

Debt Instrument, Unamortized Discount (Premium), Net

$ 3,455,000,000

$ 2,986,000,000

10,000,000

17,000,000

Short-term debt

405,000,000

Current portion of long-term debt

3,465,000,000

3,003,000,000

450,000,000

Debt Issuance Costs, Gross

^[1]

15,000,000

10,000,000

Long-term Debt, Excluding Current Maturities

2,595,000,000

2,993,000,000

Loans Payable [Member] | Term Loan Facility in 2015 [Member]

Debt Instrument, Unamortized Discount (Premium), Net

450,000,000

Senior Notes | Senior Notes, Due in 2019 [Member]

450,000,000

Debt Instrument, Unamortized Discount (Premium), Net

500,000,000

Senior Notes | Senior Notes, Due in 2024 [Member]

500,000,000

Debt Instrument, Unamortized Discount (Premium), Net

600,000,000

(1,000,000)

Senior Notes | Senior Notes due 2027

600,000,000

599,000,000

Debt Instrument, Unamortized Discount (Premium), Net

700,000,000

(3,000,000)

Less: Unamortized debt expense

697,000,000

6,000,000

Senior Notes | Senior Notes, Due in 2044 [Member]

Debt Instrument, Unamortized Discount (Premium), Net

550,000,000

Revolving Credit Facility

550,000,000

Debt Instrument, Unamortized Discount (Premium), Net

636,000,000

636,000,000

Debt Instrument, Unamortized Discount (Premium), Net

Short-term debt

405,000,000

Subsidiary of Common Parent [Member] | Senior Notes | EOIT Senior Notes [Member]

Debt Instrument, Unamortized Discount (Premium), Net

250,000,000

13,000,000

18,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

$ 263,000,000

$ 268,000,000

[1]	As of December 31, 2017 and 2016, there was an additional $3 million and $5 million, respectively, of unamortized debt expense related to the Revolving Credit Facility included in Other long-term assets, not included above. Unamortized debt expense is amortized over the life of the respective debt.

Debt - Maturities of Long Term Debt (Details) $ in Millions	Dec. 31, 2017 USD ($)
Debt Disclosure [Abstract]
Long-term debt maturities in 2018	$ 855
Long-term debt maturities in 2019	500
Long-term debt maturities in 2020	250
Long-term debt maturities in 2021	0
Long-term debt maturities in 2022	0
Thereafter	$ 1,850

Debt - Narrative (Details)			12 Months Ended
Debt - Narrative (Details)	Mar. 09, 2017 USD ($)	Jul. 31, 2015 USD ($) time	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 18, 2015 USD ($)	May 27, 2014 USD ($)	Jan. 31, 2014 USD ($)
Debt Instrument [Line Items]
Commercial paper, authorized							$ 1,400,000,000
Commercial Paper			$ 405,000,000	$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Debt Issuance Costs, Line of Credit Arrangements, Net			3,000,000	5,000,000
Maximum borrowing capacity					$ 1,750,000,000
Letters of credit principal advances			0
Letters of credit outstanding amount			$ 3,000,000
Unused capacity, commitment fee percentage			0.20%
Covenant, acceleration of indebtedness, threshold amount			$ 100,000,000
Covenant, acceleration of indebtedness, nonpayment of uninsured money judgments, threshold amount			$ 100,000,000
Revolving Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate percentage			1.50%
Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Threshold for debt covenant ratio			$ 25,000,000
Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Consolidated debt to EBITDA ratio			5.00
Threshold for debt covenant ratio for acquisitions			5.50
Unsecured Debt \| 2015 Term Loan Facility
Debt Instrument [Line Items]
Weighted average interest rate percentage			2.45%
Term loan facility, term		3 years
Face amount		$ 450,000,000
Additional term of loan		1 year
Minimum prepayment amount		$ 1,000,000
Amount of multiple to prepay the amount outstanding		$ 500,000
Principal amount of term loan facility			$ 450,000,000
Unsecured Debt \| 2015 Term Loan Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate percentage			1.375%
Unsecured Debt \| 2015 Term Loan Facility \| Maximum
Debt Instrument [Line Items]
Number of times option may be exercised \| time		2
Senior Notes \| Senior Notes due 2027
Debt Instrument [Line Items]
Face amount	$ 700,000,000
Fixed percentage interest rate	4.40%
Proceeds from Issuance of Senior Long-term Debt	$ 691,000,000
Unamortized discount			$ 3,000,000
Unamortized debt expense			$ 6,000,000
Effective interest rate percentage			4.56%
Senior Notes \| 2.400% Senior Notes
Debt Instrument [Line Items]
Face amount						$ 500,000,000
Fixed percentage interest rate						2.40%
Effective interest rate percentage			2.58%
Senior Notes \| 3.900% Senior Notes
Debt Instrument [Line Items]
Face amount						$ 600,000,000
Fixed percentage interest rate						3.90%
Effective interest rate percentage			4.02%
Senior Notes \| 5.000% Senior Notes
Debt Instrument [Line Items]
Face amount						$ 550,000,000
Fixed percentage interest rate						5.00%
Effective interest rate percentage			5.08%
Senior Notes \| Senior Notes including 2019 Notes, 2024 Notes, and 2044 Notes
Debt Instrument [Line Items]
Unamortized debt expense			$ 9,000,000
Senior Notes \| 6.25% Senior Notes
Debt Instrument [Line Items]
Face amount			$ 250,000,000
Fixed percentage interest rate			6.25%
Effective interest rate percentage			3.83%
Premium (Discount) on long-term debt			$ 13,000,000
Commercial Paper
Debt Instrument [Line Items]
Weighted average interest rate percentage			2.42%
Commercial Paper			$ 405,000,000	$ 0

Fair Value Measurements - Estimated Fair Value of Financial Instruments and Non-Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($)

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

$ 405,000,000

$ 0

Fair Value, Measurements, Nonrecurring | Transportation and Storage | Pipelines

9,000,000

$ 1,134,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Impairment of jurisdictional pipelines

12,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | Revolving Credit Facility (Level 2)

405,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | 2015 Term Loan Agreement (Level 2)

^[1]

636,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | Senior Notes, Due in 2019 [Member]

450,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | Senior Notes, Due in 2024 [Member]

497,000,000

490,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | Senior Notes due 2027

602,000,000

564,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | Senior Notes, Due in 2044 [Member]

712,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Significant other observable inputs (Level 2) | EOIT Senior Notes (Level 2)

550,000,000

467,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Unobservable inputs (Level 3) | Fair Value, Measurements, Nonrecurring | Gathering and Processing | Service Star Assets | Income Approach Valuation Technique

265,000,000

260,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Unobservable inputs (Level 3) | Fair Value, Measurements, Nonrecurring | Gathering and Processing | Atoka Assets | Income Approach Valuation Technique

9,000,000

10,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Write down of intangibles

25,000,000

6,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

8,000,000

9,000,000

Write down of property plant and equipment

19,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | Revolving Credit Facility (Level 2)

1,000,000

$ 1,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | 2015 Term Loan Agreement (Level 2)

^[1]

636,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | Senior Notes, Due in 2019 [Member]

450,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | Senior Notes, Due in 2024 [Member]

500,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | Senior Notes due 2027

600,000,000

599,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | Senior Notes, Due in 2044 [Member]

697,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Carrying Amount | Significant other observable inputs (Level 2) | EOIT Senior Notes (Level 2)

550,000,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

$ 263,000,000

$ 268,000,000

[1]	Borrowing capacity is effectively reduced by our borrowings outstanding under the commercial paper program. $405 million and zero of commercial paper was outstanding as of December 31, 2017 and 2016, respectively.

Fair Value Measurements - Fair Value Hierarchy (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Fuel reserves for under retained fuel due from shippers

$ 0

$ 9

$ 1,134

Fuel reserves for over retained fuel due from shippers

Recurring Measurement | Commodity Contracts

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Derivative asset, fair value, before netting adjustments

Derivative liability, fair value, before netting adjustments

Derivative asset, netting adjustment

(5)

Derivative liability, netting adjustment

(5)

Recurring Measurement | Gas Imbalances

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Derivative asset, fair value, before netting adjustments

^[1],[2]

Derivative liability, fair value, before netting adjustments

^[2],[3]

Derivative asset, netting adjustment

^[1],[2]

Derivative liability, netting adjustment

^[2],[3]

^[1],[2]

Recurring Measurement | Quoted market prices in active market for identical assets (Level 1) | Commodity Contracts

^[2],[3]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Recurring Measurement | Quoted market prices in active market for identical assets (Level 1) | Gas Imbalances

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

^[1],[2]

Recurring Measurement | Significant other observable inputs (Level 2) | Commodity Contracts

^[2],[3]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Recurring Measurement | Significant other observable inputs (Level 2) | Gas Imbalances

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

^[1],[2]

Recurring Measurement | Unobservable inputs (Level 3) | Commodity Contracts

^[2],[3]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Recurring Measurement | Unobservable inputs (Level 3) | Gas Imbalances

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

^[1],[2]

Service Star Assets | Income Approach Valuation Technique | Gathering and Processing | Fair Value, Measurements, Nonrecurring | Unobservable inputs (Level 3)

^[2],[3]

$ 0

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Atoka Assets | Income Approach Valuation Technique | Gathering and Processing | Fair Value, Measurements, Nonrecurring | Unobservable inputs (Level 3)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Impairment of Intangible Assets (Excluding Goodwill)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Tangible Asset Impairment Charges

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Pipelines | Transportation and Storage | Fair Value, Measurements, Nonrecurring

$ 1

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Impairment of Long-Lived Assets Held-for-use

$ 12

[1]	Gas imbalance assets exclude fuel reserves for under retained fuel due from shippers of $10 million and zero at December 31, 2017 and 2016, respectively, which fuel reserves are based on the value of natural gas at the time the imbalance was created and which are not subject to revaluation at fair market value.
[2]	The Partnership uses the market approach to fair value its gas imbalance assets and liabilities at individual, or where appropriate an average of, current market indices applicable to the Partnership’s operations, not to exceed net realizable value. Gas imbalances held by EOIT are valued using an average of the Inside FERC Gas Market Report for Panhandle Eastern Pipe Line Co. (Texas, Oklahoma Mainline), ONEOK (Oklahoma) and ANR Pipeline (Oklahoma) indices. There were no netting adjustments as of December 31, 2017 and 2016.
[3]	Gas imbalance liabilities exclude fuel reserves for over retained fuel due to shippers of zero and $5 million at December 31, 2017 and 2016, respectively, which fuel reserves are based on the value of natural gas at the time the imbalance was created and which are not subject to revaluation at fair market value.

Fair Value Measurements - Schedule of Changes in Fair Values of Level 3 Financial Assets (Details) - Natural gas liquids financial futures/swaps - Commodity Contracts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	$ (8)	$ 4
Gains (Losses) included in earnings	(9)	(13)
Settlements	12	1
Transfers out of Level 3	0	0
Ending Balance	$ (5)	$ (8)

Fair Value Measurements - Schedule of Quantitative Information on Level 3 Fair Value Inputs (Details)
$ in Millions

12 Months Ended

Dec. 31, 2017

USD ($)

$ / gal

Dec. 31, 2016

USD ($)

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Fuel reserves for under retained fuel due from shippers

$ 10

$ 0

Fuel reserves for over retained fuel due from shippers

Commodity Contracts | Natural gas liquids financial futures/swaps | Market Approach Valuation Technique | Unobservable inputs (Level 3)

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Commodity Contracts | Natural gas liquids financial futures/swaps | Minimum | Market Approach Valuation Technique | Unobservable inputs (Level 3)

$ (5)

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Forward Curve Range (Per gallon) | $ / gal

0.267

Commodity Contracts | Natural gas liquids financial futures/swaps | Maximum | Market Approach Valuation Technique | Unobservable inputs (Level 3)

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Forward Curve Range (Per gallon) | $ / gal

1.090

Recurring Measurement | Gas Imbalances

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset

^[1],[2]

$ 0

Recurring Measurement | Commodity Contracts

^[2],[3]

(12)

(30)

Fair Value Inputs, Assets, Quantitative Information [Line Items]

Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset

$ (8)

$ (34)

[1]	Gas imbalance assets exclude fuel reserves for under retained fuel due from shippers of $10 million and zero at December 31, 2017 and 2016, respectively, which fuel reserves are based on the value of natural gas at the time the imbalance was created and which are not subject to revaluation at fair market value.
[2]	The Partnership uses the market approach to fair value its gas imbalance assets and liabilities at individual, or where appropriate an average of, current market indices applicable to the Partnership’s operations, not to exceed net realizable value. Gas imbalances held by EOIT are valued using an average of the Inside FERC Gas Market Report for Panhandle Eastern Pipe Line Co. (Texas, Oklahoma Mainline), ONEOK (Oklahoma) and ANR Pipeline (Oklahoma) indices. There were no netting adjustments as of December 31, 2017 and 2016.
[3]	Gas imbalance liabilities exclude fuel reserves for over retained fuel due to shippers of zero and $5 million at December 31, 2017 and 2016, respectively, which fuel reserves are based on the value of natural gas at the time the imbalance was created and which are not subject to revaluation at fair market value.

Derivative Instruments and Hedging Activities - Quantitative Disclosures Related to Derivative Instruments (Details)
bbl in Millions, MMBTU in Millions

12 Months Ended

Dec. 31, 2017

USD ($)

MMBTU

bbl

Dec. 31, 2016

USD ($)

MMBTU

bbl

Designated cash flow hedges | $

$ 0

Fair value hedges | $

$ 0

Not Designated as Hedging Instrument | Financial fixed futures/swaps | Purchases

Not Designated as Hedging Instrument | Financial fixed futures/swaps | Sales

^[1]

Not Designated as Hedging Instrument | Financial basis futures/swaps | Purchases

^[1]

Not Designated as Hedging Instrument | Financial basis futures/swaps | Sales

^[1]

Not Designated as Hedging Instrument | Physical purchases/sales | Purchases

^[1]

Not Designated as Hedging Instrument | Physical purchases/sales | Sales

^[1]

Not Designated as Hedging Instrument | Financial futures/swaps- Crude oil (for condensate) | Purchases

^[1]

Not Designated as Hedging Instrument | Financial futures/swaps- Crude oil (for condensate) | Sales

^[2]

Not Designated as Hedging Instrument | Financial futures/swaps- Natural gas liquids | Purchases

^[2]

564

540

Not Designated as Hedging Instrument | Financial futures/swaps- Natural gas liquids | Sales

^[3]

Not Designated as Hedging Instrument | Natural gas

^[3]

1,615

1,133

Percent of contract with durations of one year or less

67.70%

100.00%

Percent of contracts with durations of more than one year and less than two years

16.10%

Percent of contracts having durations of more than two years

16.20%

Not Designated as Hedging Instrument | Crude oil (for condensate)

Percent of contract with durations of one year or less

100.00%

Not Designated as Hedging Instrument | Volume of natural gas liquids

Percent of contract with durations of one year or less

100.00%

[1]	As of December 31, 2017, 67.7% of the natural gas contracts have durations of one year or less, 16.1% have durations of more than one year and less than two years and 16.2% have durations of more than two years. As of December 31, 2016, 100.0% of the natural gas contracts had durations of one year or less.
[2]	As of December 31, 2017 and 2016, 100% of the crude oil (for condensate) contracts have durations of one year or less.
[3]	As of December 31, 2017 and 2016, 100.0% of the natural gas liquid contracts have durations of one year or less.

Derivative Instruments and Hedging Activities - Balance Sheet Location (Details) - Not Designated as Hedging Instrument - USD ($)
$ in Millions

Dec. 31, 2017

Dec. 31, 2016

^[1]

$ 9

$ 2

Natural gas | Financial futures/swaps | Other Current

^[1]

Natural gas | Financial futures/swaps | Other Current

Natural gas | Physical purchases/sales | Other Current

Natural gas | Physical purchases/sales | Other Current

Crude oil (for condensate) | Financial futures/swaps | Other Current

Crude oil (for condensate) | Financial futures/swaps | Other Current

Natural gas liquids financial futures/swaps | Financial futures/swaps | Other Current

Natural gas liquids financial futures/swaps | Financial futures/swaps | Other Current

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

$ 5

$ 8

[1]	See Note 12 for a reconciliation of the Partnership’s total derivatives fair value to the Partnership’s Consolidated Balance Sheets as of December 31, 2017 and 2016.

Derivative Instruments and Hedging Activities - Amounts Recognized in Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative, net	$ 19	$ (43)	$ 39
Change in fair value of derivatives	28	(60)	(8)
Realized gain (loss) on derivatives	(9)	17	47
Gain (loss) on derivative activity	19	(43)	39
Cash collateral posted	7
Natural gas \| Physical purchases/sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative, net	20	(19)	26
Natural gas \| Financial futures/swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative, net	9	(7)	(9)
Crude oil (for condensate) \| Financial futures/swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative, net	(1)	(4)	12
Natural gas liquids financial futures/swaps \| Financial futures/swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative, net	$ (9)	$ (13)	$ 10

Supplemental Disclosure of Cash Flow Information - Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Information [Abstract]
Interest, net of capitalized interest	$ 114	$ 105	$ 85
Income taxes, net of refunds	0	0	1
Accounts payable related to capital expenditures	39	18	52
Issuance of common units upon interest acquisition of SESH (Note 9)	$ 0	$ 0	$ 1

Supplemental Disclosure of Cash Flow Information - Schedule of Reconciliation of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Cash and cash equivalents	$ 5	$ 6
Restricted cash	14	17
Cash, cash equivalents and restricted cash shown in the Consolidated Statement of Cash Flows	$ 19	$ 23	$ 4	$ 12

Related Party Transactions - Narrative (Details)			12 Months Ended
Related Party Transactions - Narrative (Details)	Dec. 06, 2016 mi	Feb. 18, 2016 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) mi	Dec. 31, 2015 USD ($)
Related Party Transaction [Line Items]
Remaining net book value of pipeline segment			$ 10,355,000,000	$ 10,143,000,000
Partnership's revenues from affiliated companies as a percent of total revenues			5.00%	7.00%	7.00%
Rent and maintenance expense			$ 27,000,000	$ 27,000,000	$ 32,000,000
Rent and maintenance expenses expected to incur during the remaining term of lease			17,000,000
Proceeds from issuance of Series A Preferred Units, net of issuance costs			0	$ 362,000,000	0
Private Placement \| Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units
Related Party Transaction [Line Items]
Issuance of Series A Preferred Units (in units) \| shares		14,520,000
Cash purchase price (in dollars per unit) \| $ / shares		$ 25.00
Proceeds from issuance of Series A Preferred Units, net of issuance costs		$ 362,000,000
Pipelines
Related Party Transaction [Line Items]
Number of miles of new pipeline constructed \| mi				28.5
Number of miles of existing pipeline segments abandoned \| mi				34.2
CenterPoint and OGE Energy \| Minimum
Related Party Transaction [Line Items]
Period notice of termination for reimbursements for all employee costs				90 days
CenterPoint
Related Party Transaction [Line Items]
Outstanding long-term notes payable				$ 363,000,000
Affiliate interest expense			0	$ 1,000,000	$ 8,000,000
CenterPoint \| Certain Services and Support Functions
Related Party Transaction [Line Items]
Expense reimbursement annual caps			$ 3,000,000
OGE Energy \| Minimum
Related Party Transaction [Line Items]
Period notice of termination prior to commencement of succeeding annual period			180 days	180 days
OGE Energy \| Defined Benefit And Retiree Medical Plans
Related Party Transaction [Line Items]
Expense reimbursement in 2017			$ 5,000,000
Expense reimbursement in 2018 and thereafter			5,000,000
OGE Energy \| Certain Services and Support Functions
Related Party Transaction [Line Items]
Expense reimbursement annual caps			4,000,000
Subsidiary of Common Parent \| Amount Reimbursed for Costs Incurred in Modifications of Acquired Facility \| Pipelines
Related Party Transaction [Line Items]
Amount of reimbursement			$ 1,000,000	$ 2,000,000
Subsidiary of Common Parent \| Pipeline Sold to CenterPoint Energy's Arkansas LDC \| Pipelines
Related Party Transaction [Line Items]
Number of miles of pipeline segment sold \| mi				12.4
Remaining net book value of pipeline segment				$ 1,000,000
Subsidiary of Common Parent \| Amount Reimbursed for Costs Incurred in Connecting New Pipeline Segment \| Pipelines
Related Party Transaction [Line Items]
Amount of reimbursement				$ 7,000,000
CenterPoint \| Subsidiary of Common Parent \| Three Services included in Transportation and Storage Agreements
Related Party Transaction [Line Items]
Period of written notice prior to contract termination			180 days
CenterPoint \| Affiliate \| Lease Agreement with Affiliate of CenterPoint Energy
Related Party Transaction [Line Items]
Rent and maintenance expense			$ 1,000,000
Rent and maintenance expenses expected to incur during the remaining term of lease			$ 1,000,000
OGE Energy \| Subsidiary of Common Parent \| Transportation Agreement between OGE Energy and EOIT \| Pipelines
Related Party Transaction [Line Items]
Length of pipeline \| mi	80

Related Party Transactions - Related Party Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Revenues from affiliated companies	$ 153	$ 159	$ 162
Cost of goods sold from affiliate	20	14	17
Total seconded employee, corporate services and operating lease expense	38	40	61
CenterPoint
Related Party Transaction [Line Items]
Cost of goods sold from affiliate	1	0	2
CenterPoint \| Gas Transportation and Storage
Related Party Transaction [Line Items]
Revenues from affiliated companies	110	110	110
CenterPoint \| Gas Sales
Related Party Transaction [Line Items]
Revenues from affiliated companies	6	1	7
CenterPoint \| Corporate Services
Related Party Transaction [Line Items]
Total seconded employee, corporate services and operating lease expense	3	6	15
CenterPoint \| Operating Lease
Related Party Transaction [Line Items]
Total seconded employee, corporate services and operating lease expense	1	0	0
OGE Energy
Related Party Transaction [Line Items]
Cost of goods sold from affiliate	19	14	15
OGE Energy \| Gas Transportation and Storage
Related Party Transaction [Line Items]
Revenues from affiliated companies	35	36	37
OGE Energy \| Gas Sales
Related Party Transaction [Line Items]
Revenues from affiliated companies	2	12	8
OGE Energy \| Seconded Employee Costs
Related Party Transaction [Line Items]
Total seconded employee, corporate services and operating lease expense	31	29	35
OGE Energy \| Corporate Services
Related Party Transaction [Line Items]
Total seconded employee, corporate services and operating lease expense	$ 3	$ 5	$ 11

Commitments and Contingencies - Operating Leases Future Minimum Payments and Other Commitments (Details) $ in Millions	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Noncancellable operating leases due in 2018	$ 10
Noncancellable operating leases due in 2019	3
Noncancellable operating leases due in 2020	1
Noncancellable operating leases due in 2021	1
Noncancellable operating leases due in 2022	1
Noncancellable operating leases due after 2023	1
Total	$ 17

Commitments and Contingencies - Narrative (Details) $ in Millions	12 Months Ended			69 Months Ended
	Dec. 31, 2017 USD ($) ft² agreement	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) ft² agreement
Lessee, Lease, Description [Line Items]
Number of compression service agreements	104			104
Number of compression service agreements on a month-to-month basis	62			62
Number of compression service agreements expiring in 2017	34			34
Number of compression service agreements expiring in 2018	8			8
Number of gas treating agreements	6			6
Rent expense \| $	$ 27	$ 27	$ 32
Principal executive offices
Lessee, Lease, Description [Line Items]
Area of leased office space (square feet) \| ft²	162,053			162,053
Office lease payments over the lease term \| $				$ 19
Houston, Texas
Lessee, Lease, Description [Line Items]
Area of leased office space (square feet) \| ft²	48,642			48,642
Office lease payments over the lease term \| $	$ 4

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Deferred income tax benefit	$ 1,000,000
Unrecognized tax benefits	$ 0	$ 0	$ 0

Income Taxes - Schedule of Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Provision (benefit) for current income taxes
Federal	$ 1	$ (1)	$ 0
State	1	0	1
Total provision (benefit) for current income taxes	2	(1)	1
Provision (benefit) for deferred income taxes, net
Federal	(2)	3	0
State	(1)	(1)	(1)
Total provision (benefit) for deferred income taxes, net	(3)	2	(1)
Total income tax expense (benefit)	$ (1)	$ 1	$ 0

Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 436	$ 314	$ (771)
Federal statutory rate	0.00%	0.00%	0.00%
Expected federal income tax expense	$ 0	$ 0	$ 0
State income taxes, net of federal income tax	(1)	1	0
Total	(1)	1	0
Total income tax expense (benefit)	$ (1)	$ 1	$ 0
Effective tax rate	(0.20%)	0.30%	0.00%

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued bonuses	$ 17	$ 0
Total non-current deferred tax assets	17	0
Total deferred tax assets	17	0
Deferred tax liabilities:
Depreciation	5	7
Intercompany management fee	18	3
Total non-current deferred tax liabilities	23	10
Accumulated deferred income taxes, net	$ 6	$ 10

Equity Based Compensation - Performance Units, Restricted Units and Phantom Units (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity-based compensation expense	$ 15	$ 13	$ 11
Performance units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity-based compensation expense	10	9	3
Restricted units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity-based compensation expense	2	3	7
Phantom units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total equity-based compensation expense	$ 3	$ 1	$ 1
Common Units \| Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units that may be delivered pursuant to vested awards	13,100,000

Equity Based Compensation - Performance Units (Details) - Performance units - $ / shares

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Vesting period

3 years

Award cycle

3 years

Number of units granted (in units)

2 years

468,626

^[1]

1,235,429

501,474

$ 19.27

^[1]

$ 16.59

47.30%

27.60%

Expected life of units (in years)

1.57%

0.99%

3 years

Awards Granted in 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Duration of daily stock price observations to determine expected price volatility

3 years

Awards Granted in 2016

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Duration of daily stock price observations to determine expected price volatility

2 years

Average volatility period of peer group companies

1 year

Awards Granted in 2015

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Duration of daily stock price observations to determine expected price volatility

1 year

Average volatility period of peer group companies

2 years

Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Payout percentage from target level of achievement of performance goal

0.00%

$ 10.42

43.20%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

0.86%

Maximum

Payout percentage from target level of achievement of performance goal

200.00%

$ 27.77

46.00%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

0.90%

[1]	For performance units, this represents the target number of performance units granted. The actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.

Equity Based Compensation - Phantom Units (Details) - $ / shares

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Restricted units

^[1]

Restricted units | Certain Partnership Employees

^[1]

$ 0.00

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

2 years

Restricted units | Certain Partnership Employees | Minimum

279,677

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted units | Certain Partnership Employees | Maximum

$ 16.75

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

19.18

Phantom units

2 years

392,338

^[1]

653,286

Phantom units | Certain Partnership Employees and Independent Directors of Enable GP

^[1]

$ 16.24

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Phantom units | Certain Partnership Employees and Independent Directors of Enable GP | Minimum

$ 15.30

$ 12.70

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Phantom units | Certain Partnership Employees and Independent Directors of Enable GP | Maximum

15.44

$ 8.12

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Phantom units | Independent Directors Of Enable GP

$ 16.93

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Other Awards | Independent Directors Of Enable GP

9,817

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

16,653

14,914

17,384

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

$ 15.03

$ 15.35

$ 11.12

[1]	For performance units, this represents the target number of performance units granted. The actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.

Equity Based Compensation - Restricted Units and Other Awards (Details) - $ / shares

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Performance units

2 years

468,626

^[1]

1,235,429

501,474

$ 19.27

^[1]

$ 16.59

47.30%

27.60%

Performance units | Minimum

1.57%

0.99%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

$ 10.42

43.20%

Performance units | Maximum

0.86%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

$ 27.77

46.00%

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

0.90%

Restricted units

^[1]

Restricted units | Certain Partnership Employees

^[1]

$ 0.00

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

2 years

Restricted units | Certain Partnership Employees | Minimum

279,677

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted units | Certain Partnership Employees | Maximum

$ 16.75

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]

$ 19.18

[1]	For performance units, this represents the target number of performance units granted. The actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.

Equity Based Compensation - Equity Units Activity (Details) - USD ($)
$ / shares in Units, $ in Millions

9 Months Ended

12 Months Ended

Sep. 30, 2017

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Performance units

Units Outstanding at 12/31/2016 (in units)

1,969,107

468,626

^[1]

1,235,429

501,474

Units Outstanding at 12/31/2017 (in units)

^[2],[3]

(341,507)

Forfeited (in units)

^[2],[3]

(55,819)

2,040,407

1,969,107

Weighted Average Grant-Date Fair Value, Per Unit

Units Outstanding at 12/31/2016 (in dollars per share)

$ 15.27

Vested (in dollars per share)

19.27

^[1]

$ 16.59

^[2],[3]

29.29

Forfeited (in dollars per share)

^[2],[3]

14.63

Units Outstanding at 12/31/2017 (in dollars per share)

$ 13.86

$ 15.27

Aggregate intrinsic value of units vested

$ 5

Fair value of units vested

$ 10

Performance units | Minimum

Weighted Average Grant-Date Fair Value, Per Unit

Payout percentage from target level of achievement of performance goal

10.42

0.00%

Performance units | Maximum

Weighted Average Grant-Date Fair Value, Per Unit

Payout percentage from target level of achievement of performance goal

$ 27.77

200.00%

Restricted units

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]

Units Outstanding at 12/31/2016 (in units)

392,995

^[1]

Units Outstanding at 12/31/2017 (in units)

^[2],[3]

(160,485)

Forfeited (in units)

^[2],[3]

(10,076)

222,434

392,995

Weighted Average Grant-Date Fair Value, Per Unit

Units Outstanding at 12/31/2016 (in dollars per share)

$ 20.74

Vested (in dollars per share)

^[1]

0.00

^[2],[3]

24.86

Forfeited (in dollars per share)

^[2],[3]

18.74

Units Outstanding at 12/31/2017 (in dollars per share)

$ 17.87

$ 20.74

Aggregate intrinsic value of units vested

$ 2

Fair value of units vested

$ 4

Phantom units

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]

Units Outstanding at 12/31/2016 (in units)

643,604

392,338

^[1]

653,286

Units Outstanding at 12/31/2017 (in units)

^[2],[3]

(21,704)

Forfeited (in units)

^[2],[3]

(26,858)

987,380

643,604

Weighted Average Grant-Date Fair Value, Per Unit

Units Outstanding at 12/31/2016 (in dollars per share)

$ 8.49

Vested (in dollars per share)

^[1]

16.24

^[2],[3]

13.12

Forfeited (in dollars per share)

^[2],[3]

11.45

Units Outstanding at 12/31/2017 (in dollars per share)

$ 11.38

$ 8.49

Aggregate intrinsic value of units vested

$ 0

Fair value of units vested

$ 0

Annual Grant in 2014 | Performance units

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]

334,682

Weighted Average Grant-Date Fair Value, Per Unit

(306,170)

Payout percentage from target level of achievement of performance goal

91.50%

Annual Grant in 2015 | Performance units

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]

Weighted Average Grant-Date Fair Value, Per Unit

402,586

Payout percentage from target level of achievement of performance goal

100.00%

Annual Grant in 2015 | Performance units | Maximum

Weighted Average Grant-Date Fair Value, Per Unit

Payout percentage from target level of achievement of performance goal

200.00%

Certain Partnership Employees and Independent Directors of Enable GP | Phantom units

Weighted Average Grant-Date Fair Value, Per Unit

Certain Partnership Employees and Independent Directors of Enable GP | Phantom units | Minimum

15.30

$ 12.70

Weighted Average Grant-Date Fair Value, Per Unit

Certain Partnership Employees and Independent Directors of Enable GP | Phantom units | Maximum

$ 15.44

$ 8.12

Weighted Average Grant-Date Fair Value, Per Unit

$ 16.93

[1]	For performance units, this represents the target number of performance units granted. The actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.
[2]	Performance units outstanding as of December 31, 2017 include 402,586 units from the 2015 annual grant, which were approved by the Board of Directors in 2015. The results of the performance units were certified by the Compensation Committee in February 2018, at a 200% payout based on the level of achievement of a performance goal established by the Board of Directors over a performance period of January 1, 2015 through December 31, 2017. The increase in outstanding units for a payout percentage of an amount other than 100% is not reflected above until the vesting date.
[3]	Performance units vested as of December 31, 2017 include 334,682 units from the 2014 annual grant, which vested on June 1, 2017 and paid out at 91.5% of target, or 306,170 units, based on the level of achievement of a performance goal established by the Board of Directors over the performance period.

Equity Based Compensation - Unrecognized Compensation Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost (In millions)	$ 20
Long Term Incentive Plan \| Common Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance \| shares	8,662,420
Performance units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost (In millions)	$ 13
Weighted Average to be Recognized (In years)	1 year 3 months 15 days
Restricted units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost (In millions)	$ 1
Weighted Average to be Recognized (In years)	5 months 5 days
Phantom units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost (In millions)	$ 6
Weighted Average to be Recognized (In years)	1 year 6 months 29 days

Reportable Segments - Schedule of Financial Data for Business Segments and Services (Details)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2017

USD ($)

Sep. 30, 2017

USD ($)

Jun. 30, 2017

USD ($)

Mar. 31, 2017

USD ($)

Dec. 31, 2016

USD ($)

Sep. 30, 2016

USD ($)

Jun. 30, 2016

USD ($)

Mar. 31, 2016

USD ($)

Dec. 31, 2017

USD ($)

segment

Dec. 31, 2016

USD ($)

Dec. 31, 2015

USD ($)

Number of reportable segments | segment

$ 1,653

$ 1,172

$ 1,334

1,150

1,100

1,084

^[1]

2,803

2,272

2,418

Operation and maintenance, General and administrative

$ 445

$ 349

$ 279

$ 308

$ 300

$ 268

$ 254

$ 195

1,381

1,017

1,097

464

465

522

366

338

318

1,134

129

$ 137

$ 122

$ 140

$ 139

$ 57

$ 103

528

385

(712)

11,593

11,212

11,593

11,212

11,226

Operating Segments | Gathering and Processing

714

383

949

1,538

1,081

1,118

632

559

545

^[1]

2,170

1,640

1,663

Operation and maintenance, General and administrative

1,285

915

908

289

276

293

232

212

195

543

327

196

(306)

9,079

7,453

9,079

7,453

7,536

Operating Segments | Transportation and Storage

601

312

839

^[2]

621

479

590

^[2]

525

545

542

^[1],[2]

1,146

1,024

1,132

Operation and maintenance, General and administrative

^[2]

604

492

565

^[2]

179

191

230

^[2]

134

126

123

^[2]

591

^[2]

^[2]

202

189

(406)

^[2]

5,616

4,963

5,616

4,963

4,976

^[2]

113

110

Eliminations

(506)

(388)

(374)

(7)

(4)

(3)

^[1]

(513)

(392)

(377)

Operation and maintenance, General and administrative

(508)

(390)

(376)

(4)

(2)

(1)

(1)

$ (3,102)

$ (1,204)

(3,102)

(1,204)

(1,286)

Effect of Fourth Quarter Events [Line Items]

$ 0

[1]	The Partnership had no external customers accounting for 10% or more of revenues in periods shown. See Note 14 for revenues from affiliated companies.
[2]	Equity in earnings of equity method affiliate is included in Other Income (Expense) on the Consolidated Statements of Income, and is not included in the table above. See Note 9 for discussion regarding ownership interest in SESH and related equity earnings included in the transportation and storage segment for the years ended December 31, 2017, 2016 and 2015.

Quarterly Financial Data (Unaudited) - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Revenue, Net

$ 806

$ 705

$ 626

$ 666

$ 614

$ 620

$ 529

$ 509

$ 2,803

$ 2,272

$ 2,418

Net income attributable to limited partners

445

349

279

308

300

268

254

195

1,381

1,017

1,097

Operating income (loss)

129

137

122

140

139

103

528

385

(712)

Net income (loss)

108

113

120

119

437

313

(771)

108

113

120

119

436

312

(752)

Net income attributable to common and subordinated units

$ 99

$ 104

$ 86

$ 111

$ 59

$ 110

$ 35

$ 86

400

290

(752)

Goodwill impairment

1,087

Common Units

Effect of Fourth Quarter Events [Line Items]

Net income attributable to common and subordinated units

$ 273

$ 148

$ (381)

$ 0.23

$ 0.24

$ 0.20

$ 0.26

$ 0.14

$ 0.26

$ 0.08

$ 0.21

$ 0.92

$ 0.69

$ (1.78)

Effect of Fourth Quarter Events [Line Items]

0.23

0.24

0.20

0.26

0.14

0.26

0.08

0.19

$ 0.92

$ 0.69

$ (1.78)

Subordinated Units

Net income attributable to common and subordinated units

$ 127

$ 142

$ (371)

0.00

^[1]

0.24

^[1]

0.20

^[1]

0.25

^[1]

0.14

0.26

0.08

0.20

$ 0.93

$ 0.68

$ (1.78)