Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
U.S. federal income taxes:
Current	$ 356	$ 373	$ 1,117
Deferred	(26)	(15)	(10)
Total U.S. federal income taxes	330	358	1,107
Foreign income taxes:
Current	302	358	296
Deferred	53	49	102
Total foreign income taxes	355	407	398
State income taxes:
Current	77	66	106
Deferred	5	0	(28)
Total state income taxes	82	66	78
Total provision for income taxes	$ 767	$ 831	$ 1,583