Acquisitions (Details) - USD ($) $ in Millions				1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
		Mar. 18, 2019	Mar. 17, 2019	Jun. 30, 2019	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Impairment of equity-method investments					$ 0		$ (2)	$ 938	$ 72
Changes in ownership of consolidated subsidiaries, net							141		141
Impairment of goodwill (Note 12)					$ 0	$ 187	0	187	0
Noncontrolling Interests
Business Acquisition [Line Items]
Changes in ownership of consolidated subsidiaries, net							566		566
Impairment of goodwill (Note 12)						65
Capital in excess of par value [Member]
Business Acquisition [Line Items]
Changes in ownership of consolidated subsidiaries, net							$ (425)		$ (425)
Northeast JV [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners				35.00%			35.00%		35.00%
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest				65.00%
Northeast JV [Member]
Business Acquisition [Line Items]
Noncontrolling Interest in Joint Ventures				$ 1,330			$ 1,330		$ 1,330
Increase (Decrease) in Deferred Income Taxes										$ (141)
Northeast JV [Member] | Noncontrolling Interests
Business Acquisition [Line Items]
Changes in ownership of consolidated subsidiaries, net										567
Northeast JV [Member] | Capital in excess of par value [Member]
Business Acquisition [Line Items]
Changes in ownership of consolidated subsidiaries, net										$ (426)
Impairment Of Equity-Method Investments [Member]
Business Acquisition [Line Items]
Impairment of equity-method investments								$ 938	$ 72
Utica East Ohio Midstream, LLC Acquisition [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 741
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		13
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net		0
Goodwill		$ 187
Goodwill, Other Increase (Decrease)						$ (1)
Utica East Ohio Midstream, LLC [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage											62.00%
Utica East Ohio Midstream, LLC [Member] | Fair Value, Nonrecurring [Member] | Level 2 [Member] | Northeast G And P [Member] | Impairment Of Equity-Method Investments [Member]
Business Acquisition [Line Items]
Impairment of equity-method investments	[1]		$ 74
Utica East Ohio Midstream, LLC [Member] | Utica East Ohio Midstream, LLC Acquisition [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		38.00%
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage			62.00%

[1] The estimated fair value was determined by a market approach based on the transaction price for the purchase of the remaining interest in UEOM as finalized just prior to the signing and closing of the acquisition in March 2019 (see Note 2 – Acquisitions). These inputs resulted in a fair value measurement within Level 2 of the fair value hierarchy.