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General, Description of Business, and Basis of Presentation (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 10, 2018	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Apr. 30, 2019	Jan. 01, 2019
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			$ 1	$ 0	$ 142	$ (4)
Operating Lease, Liability			213		213
Operating Lease, Right-of-Use Asset			213		213
Accounting Standards Update 2016-02 [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Operating Lease, Liability								$ 225
Operating Lease, Right-of-Use Asset								$ 225
Northeast JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Increase (Decrease) in Deferred Income Taxes					$ (142)
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest		65.00%
Dividend Reinvestment Program [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Sale of Stock, Number of Shares Issued in Transaction						1,230,657
Sale of Stock, Consideration Received on Transaction						$ 46
Northeast G And P [Member] \| Cardinal Gas Services LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage					66.00%
Northeast G And P [Member] \| Appalachia Midstream Services, LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest					66.00%
Northeast G And P [Member] \| Northeast JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage					65.00%
Atlantic Gulf [Member] \| Constitution Pipeline Company LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage					41.00%
Atlantic Gulf [Member] \| Gulfstar One [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage					51.00%
West [Member] \| Conway Fractionator [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest					50.00%
Common Stock
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			0	0	$ 0	0
Capital in excess of par value [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			(1)	1	(426)	14
Capital in excess of par value [Member] \| Northeast JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net					(426)
AOCI
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			0	0	0	0
Noncontrolling Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			$ 2	$ (1)	568	$ (18)
Noncontrolling Interest [Member] \| Northeast JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net					$ 568
WPZ Merger Agreement [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Limited Partners' Capital Account, Units Outstanding	256,000,000
Stock Issued During Period, Shares, New Issues	382,000,000
Increase (Decrease) in Other Noncurrent Assets	$ 33
Increase (Decrease) in Deferred Income Taxes	(1,829)
WPZ Merger Agreement [Member] \| Common Stock
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	382
WPZ Merger Agreement [Member] \| Capital in excess of par value [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	6,112
WPZ Merger Agreement [Member] \| AOCI
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	(3)
WPZ Merger Agreement [Member] \| Noncontrolling Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net	$ (4,629)
Laurel Mountain Midstream, LLC [Member] \| Northeast G And P [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			69.00%		69.00%
Caiman Energy II [Member] \| Northeast G And P [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			58.00%		58.00%
Gulfstream Natural Gas System, L.L.C.[Member] \| Atlantic Gulf [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%		50.00%
Discovery Producer Services LLC [Member] \| Atlantic Gulf [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			60.00%		60.00%
Overland Pass Pipeline Company LLC [Member] \| West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%		50.00%
Rocky Mountain Midstream Holdings LLC [Member] \| West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%		50.00%
Brazos Permian II LLC [Member] \| West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			15.00%		15.00%
Jackalope Gas Gathering Services LLC [Member] \| West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage							50.00%