Income Taxes - Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 2,615	$ 2,450	$ 1,480
State	518	565	499
Total current taxes	3,133	3,015	1,979
Deferred:
Federal	(450)	(535)	22
State	(114)	(114)	1
Total deferred income taxes	(564)	(649)	23
Total	$ 2,569	$ 2,366	$ 2,002