Income Taxes (Schedule of Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current income tax expense:
United States federal	$ (17)	$ 178	$ 836
United States state and local	46	30	38
International	324	177	133
Total current income tax expense	353	385	1,007
Deferred income tax (benefit) expense:
United States federal	10	(44)	84
United States state and local	(1)	(20)	(9)
International	117	(1,518)	(39)
Total deferred income tax (benefit) expense	126	(1,582)	36
Total income tax (benefit) expense	$ 479	$ (1,197)	$ 1,043