Income Taxes (Components of Earnings Before Income Taxes Between Domestic and Foreign Jurisdictions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S.	$ (14,882)	$ (2,792)	$ 11,166
Non-U.S.	406	533	438
(Loss)/earnings before income taxes	$ (14,476)	$ (2,259)	$ 11,604