(Loss)/Earnings Per Share - Schedule of Computation for Earnings Per Share Types (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net (loss)/income	$ (534)	$ 730
Basic weighted average shares outstanding (shares)	637	665
Dilutive effect of share-based awards (shares)	0	2
Diluted weighted average shares outstanding (shares)	637	667
Basic (loss)/earnings per share (USD per share)	$ (0.84)	$ 1.10
Diluted (loss)/earnings per share (USD per share)	$ (0.84)	$ 1.09