CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Adjustment for change in accounting standard	Preferred stock	Common stock shares (in thousands)	Accumulated paid-in capital	Retained earnings	Retained earnings Adjustment for change in accounting standard	Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	$ 4,893	$ 2	$ 440		$ 1,754	$ 5,811	$ 2	$ (3,112)
Balance at beginning of period at Dec. 31, 2022	4,893	$ 2	440		1,754	5,811	$ 2	(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	379					379
Other comprehensive income (loss), net of tax	182							182
Bank common stock repurchased (in shares)				(953)
Bank common stock repurchased	(50)				(50)
Net activity under employee plans and related tax benefits (in shares)				433
Net activity under employee plans and related tax benefits	18				18
Dividends on preferred stock	(15)					(15)
Dividends on common stock	(122)					(122)
Change in deferred compensation	(4)					(4)
Balance at end of period at Jun. 30, 2023	5,283		440		1,722	6,051		(2,930)
Balance at end of period (in shares) at Jun. 30, 2023				148,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	5,184		440		1,715	5,949		(2,920)
Balance at beginning of period at Mar. 31, 2023	5,184		440		1,715	5,949		(2,920)
Balance at beginning of period (in shares) at Mar. 31, 2023				148,100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	175					175
Other comprehensive income (loss), net of tax	(10)							(10)
Net activity under employee plans and related tax benefits (in shares)				44
Net activity under employee plans and related tax benefits	7				7
Dividends on preferred stock	(9)					(9)
Dividends on common stock	(61)					(61)
Change in deferred compensation	(3)					(3)
Balance at end of period at Jun. 30, 2023	5,283		440		1,722	6,051		(2,930)
Balance at end of period (in shares) at Jun. 30, 2023				148,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	5,283		440		1,722	6,051		(2,930)
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	5,691		440		1,731	6,212		(2,692)
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	$ 354					354
Other comprehensive income (loss), net of tax	143							143
Bank common stock repurchased (in shares)				(890)
Bank common stock repurchased	(35)				(35)
Net activity under employee plans and related tax benefits (in shares)				421
Net activity under employee plans and related tax benefits	17				17
Dividends on preferred stock	(21)					(21)
Dividends on common stock	(122)					(122)
Change in deferred compensation	(2)					(2)
Balance at end of period at Jun. 30, 2024	$ 6,025		440		1,713	6,421		(2,549)
Balance at end of period (in shares) at Jun. 30, 2024	147,684			147,684
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	$ 5,829		440		1,705	6,293		(2,609)
Balance at beginning of period at Mar. 31, 2024	5,829		440		1,705	6,293		(2,609)
Balance at beginning of period (in shares) at Mar. 31, 2024				147,653
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	201					201
Other comprehensive income (loss), net of tax	60							60
Net activity under employee plans and related tax benefits (in shares)				31
Net activity under employee plans and related tax benefits	8				8
Dividends on preferred stock	(11)					(11)
Dividends on common stock	(61)					(61)
Change in deferred compensation	(1)					(1)
Balance at end of period at Jun. 30, 2024	$ 6,025		440		1,713	6,421		(2,549)
Balance at end of period (in shares) at Jun. 30, 2024	147,684			147,684
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	$ 6,025		$ 440		$ 1,713	$ 6,421		$ (2,549)