Income Taxes - Applicable Income Taxes Included in the Consolidated Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax expense:
U.S. Federal income taxes	$ 463	$ 788	$ 463
State and local income taxes	69	148	71
Foreign income taxes	0	0	8
Total current income tax expense	532	936	542
Deferred income tax (benefit) expense:
U.S. Federal income taxes	(140)	(212)	24
State and local income taxes	(23)	(35)	4
Foreign income taxes	1	1	2
Total deferred income tax (benefit) expense	(162)	(246)	30
Applicable income tax expense	$ 370	$ 690	$ 572