Revenue Recognition Revenue by Category (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 2,021	$ 2,075	$ 4,055	$ 4,143
Total revenues		2,041	2,091	4,095	4,179
Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		365	306	688	631
Total revenues		370	311	698	641
Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		191	217	394	443
Total revenues		191	224	398	452
West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		834	1,067	1,714	2,093
Total revenues		842	1,065	1,726	2,096
Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		589	481	1,183	967
Total revenues		591	483	1,188	972
Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		110	108	224	220
Total revenues		110	108	224	220
Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	1	0	1
Total revenues		8	8	15	16
Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(68)	(105)	(148)	(212)
Total revenues		(71)	(108)	(154)	(218)
NonRegulated Service Monetary Consideration [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		750	730	1,443	1,459
NonRegulated Service Monetary Consideration [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		291	205	530	407
NonRegulated Service Monetary Consideration [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		121	128	249	265
NonRegulated Service Monetary Consideration [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		355	414	699	822
NonRegulated Service Monetary Consideration [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NonRegulated Service Monetary Consideration [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NonRegulated Service Monetary Consideration [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	1	0	1
NonRegulated Service Monetary Consideration [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(17)	(18)	(35)	(36)
NonRegulated Service Commodity Consideration [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		56	94	120	195
NonRegulated Service Commodity Consideration [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		3	5	8	9
NonRegulated Service Commodity Consideration [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		13	11	26	26
NonRegulated Service Commodity Consideration [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		40	78	86	160
NonRegulated Service Commodity Consideration [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NonRegulated Service Commodity Consideration [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NonRegulated Service Commodity Consideration [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NonRegulated Service Commodity Consideration [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Regulated Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		673	558	1,357	1,130
Regulated Service [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Regulated Service [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Regulated Service [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Regulated Service [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		565	450	1,135	911
Regulated Service [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		110	108	224	220
Regulated Service [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Regulated Service [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(2)	0	(2)	(1)
Other Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		50	34	93	69
Other Service [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		34	21	66	42
Other Service [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		9	2	13	8
Other Service [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		9	13	20	24
Other Service [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1	1	1	1
Other Service [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Other Service [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
Other Service [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(3)	(3)	(7)	(6)
Total Service Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		1,529	1,416	3,013	2,853
Total Service Revenues [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		328	231	604	458
Total Service Revenues [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		143	141	288	299
Total Service Revenues [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		404	505	805	1,006
Total Service Revenues [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		566	451	1,136	912
Total Service Revenues [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		110	108	224	220
Total Service Revenues [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	1	0	1
Total Service Revenues [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(22)	(21)	(44)	(43)
NGL And Natural Gas Product Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		492	656	1,042	1,283
NGL And Natural Gas Product Sales [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		37	75	84	173
NGL And Natural Gas Product Sales [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		48	76	106	144
NGL And Natural Gas Product Sales [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		430	558	909	1,079
NGL And Natural Gas Product Sales [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		23	30	47	55
NGL And Natural Gas Product Sales [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NGL And Natural Gas Product Sales [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		0	0	0	0
NGL And Natural Gas Product Sales [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax		(46)	(83)	(104)	(168)
Other Product Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			3		7
Other Product Sales [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Other Product Sales [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Other Product Sales [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			4		8
Other Product Sales [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Other Product Sales [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Other Product Sales [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Other Product Sales [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			(1)		(1)
Total Product Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	[1]		659		1,290
Total Product Sales [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			75		173
Total Product Sales [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			76		144
Total Product Sales [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			562		1,087
Total Product Sales [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			30		55
Total Product Sales [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Total Product Sales [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0
Total Product Sales [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			(84)		(169)
Product and Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		20	16	40	36
Product and Service, Other [Member] | Northeast Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		5	5	10	10
Product and Service, Other [Member] | Atlantic Gulf Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		0	7	4	9
Product and Service, Other [Member] | West Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		8	(2)	12	3
Product and Service, Other [Member] | Transco [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		2	2	5	5
Product and Service, Other [Member] | Northwest Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		0	0	0	0
Product and Service, Other [Member] | Other Geographical [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		8	7	15	15
Product and Service, Other [Member] | Intercompany Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue Not From Contract With Customer		$ (3)	$ (3)	$ (6)	$ (6)

[1] Service revenues in our Consolidated Statement of Income include leasing revenues associated with our headquarters building and management fees that we receive for certain services we provide to operated equity-method investments. The leasing revenues and the management fees do not constitute revenue from contracts with customers. Product sales in our Consolidated Statement of Income include amounts associated with our derivative contracts that are not within the scope of ASC 606, “Revenue from Contracts with Customers.