Investing Activities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity earnings (losses)	$ 22	$ 80
Impairment of equity-method investments (Note 11)	938	$ 74
Rocky Mountain Midstream Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings (losses)	$ (78)

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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