Acquisitions (Details) - USD ($) $ in Millions				1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 18, 2019	Mar. 17, 2019		Jun. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Impairment of equity-method investments					$ 938	$ 74
Impairment of goodwill (Note 11)					187	0
Noncontrolling Interests
Business Acquisition [Line Items]
Impairment of goodwill (Note 11)					65
Northeast JV [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners				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
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)
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		$ 74	[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.