Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	$ 290	$ 312	$ 759	$ 1,142
Gain (loss) on derivative activity	(10)	8	5	14
Total Revenues	596	699	1,759	2,229
Natural gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	67	95	187	351
Natural gas liquids
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	208	191	523	698
Condensate Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	15	26	49	93
Product
Disaggregation of Revenue [Line Items]
Total Revenues	280	320	764	1,156
Demand Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	148	216	476	598
Volume Dependant Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	168	163	519	475
Natural Gas, Gathering, Transportation, Marketing and Processing
Disaggregation of Revenue [Line Items]
Total Revenues	316	379	995	1,073
Operating Segments | Gathering and Processing
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	281	286	733	1,082
Gain (loss) on derivative activity	(10)	8	6	14
Total Revenues	463	542	1,331	1,759
Operating Segments | Gathering and Processing | Natural gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	58	69	161	291
Operating Segments | Gathering and Processing | Natural gas liquids
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	208	191	523	698
Operating Segments | Gathering and Processing | Condensate Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	15	26	49	93
Operating Segments | Gathering and Processing | Product
Disaggregation of Revenue [Line Items]
Total Revenues	271	294	739	1,096
Operating Segments | Gathering and Processing | Demand Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	32	97	105	225
Operating Segments | Gathering and Processing | Volume Dependant Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	160	151	487	438
Operating Segments | Gathering and Processing | Natural Gas, Gathering, Transportation, Marketing and Processing
Disaggregation of Revenue [Line Items]
Total Revenues	192	248	592	663
Operating Segments | Transportation and Storage
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	79	100	214	381
Gain (loss) on derivative activity	0	0	(1)	0
Total Revenues	205	234	622	802
Operating Segments | Transportation and Storage | Natural gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	77	95	207	365
Operating Segments | Transportation and Storage | Natural gas liquids
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	2	5	7	16
Operating Segments | Transportation and Storage | Condensate Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	0	0	0	0
Operating Segments | Transportation and Storage | Product
Disaggregation of Revenue [Line Items]
Total Revenues	79	100	213	381
Operating Segments | Transportation and Storage | Demand Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	116	119	371	373
Operating Segments | Transportation and Storage | Volume Dependant Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	10	15	38	48
Operating Segments | Transportation and Storage | Natural Gas, Gathering, Transportation, Marketing and Processing
Disaggregation of Revenue [Line Items]
Total Revenues	126	134	409	421
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	(70)	(74)	(188)	(321)
Gain (loss) on derivative activity	0	0	0	0
Total Revenues	(72)	(77)	(194)	(332)
Eliminations | Natural gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	(68)	(69)	(181)	(305)
Eliminations | Natural gas liquids
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	(2)	(5)	(7)	(16)
Eliminations | Condensate Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues from natural gas, natural gas liquids, and condensate	0	0	0	0
Eliminations | Product
Disaggregation of Revenue [Line Items]
Total Revenues	(70)	(74)	(188)	(321)
Eliminations | Demand Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	0	0	0	0
Eliminations | Volume Dependant Service Revenue
Disaggregation of Revenue [Line Items]
Total Revenues	(2)	(3)	(6)	(11)
Eliminations | Natural Gas, Gathering, Transportation, Marketing and Processing
Disaggregation of Revenue [Line Items]
Total Revenues	$ (2)	$ (3)	$ (6)	$ (11)