Earnings/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income/(loss)	$ 1,212	$ 652	$ (1,177)	$ (5,379)	$ (5,717)	$ (534)	$ 688	$ (11,630)
Basic weighted average shares outstanding (shares)	637			635			636	636
Dilutive effect of share-based awards (shares)	4			0			5	0
Diluted weighted average shares outstanding (shares)	641			635			641	636
Basic earnings/(loss) per share (USD per share)	$ 1.90			$ (8.47)			$ 1.08	$ (18.30)
Diluted earnings/(loss) per share (USD per share)	$ 1.89			$ (8.47)			$ 1.07	$ (18.30)