Income Taxes (Applicable Income Taxes Included in the Consolidated Statements of Income) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation Of Provision Of Income Taxes
U.S. Federal income taxes	$ 788	$ 463	$ 986
State and local income taxes	148	71	68
Foreign income taxes	0	8	(3)
Total current tax expense (benefit)	936	542	1,051
U.S. Federal income taxes	(212)	24	(254)
State and local income taxes	(35)	4	2
Foreign income taxes	1	2	0
Total deferred tax expense (benefit)	(246)	30	(252)
Applicable income tax expense	$ 690	$ 572	$ 799