The Merger - Pro Forma Information (Details) - Anadarko - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Revenues	$ 7,335	$ 8,913	$ 22,419	$ 23,095
Net income (loss) attributable to common stockholders	$ (427)	$ 2,060	$ 475	$ 3,405
Net income (loss) attributable to common stockholders per share—basic (in usd per share)	$ (0.50)	$ 2.27	$ 0.51	$ 3.74
Net income (loss) attributable to common stockholders per share—diluted (in usd per share)	$ (0.50)	$ 2.26	$ 0.50	$ 3.73