Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities available for sale, tax	$ 309	$ (59)	$ 871	$ 139
Net unrealized gains (losses) on derivative financial instruments, tax	82	45	259	48
Net pension and postretirement benefit costs, tax	$ (1)	$ (1)	$ (2)	$ (2)