Consolidated Statements of Changes In Shareholders' Equity - USD ($) $ in Millions	Total	Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	Preferred stock	Common stock	Accumulated paid-in capital	Retained earnings	Retained earnings Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	Accumulated other comprehensive income (loss)
Balance at beginning of period at Dec. 31, 2021	$ 7,463		$ 440	$ 0	$ 1,928	$ 5,175		$ (80)
Balance at beginning of period (in shares) at Dec. 31, 2021				151,625,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	203					203
Other comprehensive income (loss), net of tax	(1,266)							(1,266)
Bank common stock repurchased (in shares)				(778,000)
Bank common stock repurchased	(51)				(51)
Net activity under employee plans and related tax benefits (in shares)				501,000
Net activity under employee plans and related tax benefits	12				12
Dividends on preferred stock	(8)					(8)
Dividends on common stock	(58)					(58)
Change in deferred compensation	(1)					(1)
Balance at end of period at Mar. 31, 2022	6,294		440	$ 0	1,889	5,311		(1,346)
Balance at end of period (in shares) at Mar. 31, 2022				151,348,000
Balance at beginning of period at Dec. 31, 2022	$ 4,893		440	$ 0	1,754	5,811		(3,112)
Balance at beginning of period (in shares) at Dec. 31, 2022	148,664,000			148,664,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	$ 204					204
Other comprehensive income (loss), net of tax	$ 192							192
Bank common stock repurchased (in shares)	(900,000)			(953,000)
Bank common stock repurchased	$ (50)				(50)
Net activity under employee plans and related tax benefits (in shares)				389,000
Net activity under employee plans and related tax benefits	11				11
Dividends on preferred stock	(6)					(6)
Dividends on common stock	(61)					(61)
Change in deferred compensation	(1)					(1)
Balance at end of period at Mar. 31, 2023	$ 5,184	$ (2)	$ 440	$ 0	$ 1,715	$ 5,949	$ (2)	$ (2,920)
Balance at end of period (in shares) at Mar. 31, 2023	148,100,000			148,100,000