Consolidated Statements of Changes In Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	Preferred stock	Common stock shares (in thousands)	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, 2022	$ 4,893		$ 440		$ 1,754	$ 5,811		$ (3,112)
Balance at beginning of period (in shares) at Dec. 31, 2022				148,664
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)				(953)
Bank common stock repurchased	(50)				(50)
Net activity under employee plans and related tax benefits (in shares)				389
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		1,715	5,949	$ 2	(2,920)
Balance at end of period (in shares) at Mar. 31, 2023				148,100
Balance at beginning of period at Dec. 31, 2023	$ 5,691		440		1,731	6,212		(2,692)
Balance at beginning of period (in shares) at Dec. 31, 2023	148,153			148,153
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	$ 153					153
Other comprehensive income (loss), net of tax	$ 83							83
Bank common stock repurchased (in shares)	(900)			(890)
Bank common stock repurchased	$ (35)				(35)
Net activity under employee plans and related tax benefits (in shares)				390
Net activity under employee plans and related tax benefits	9				9
Dividends on preferred stock	(10)					(10)
Dividends on common stock	(61)					(61)
Change in deferred compensation	(1)					(1)
Balance at end of period at Mar. 31, 2024	$ 5,829		$ 440		$ 1,705	$ 6,293		$ (2,609)
Balance at end of period (in shares) at Mar. 31, 2024	147,653			147,653