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	554					554
Other comprehensive income (loss), net of tax	104							104
Bank common stock repurchased (in shares)				(953)
Bank common stock repurchased	(50)				(50)
Net activity under employee plans and related tax benefits (in shares)				435
Net activity under employee plans and related tax benefits	22				22
Dividends on preferred stock	(22)					(22)
Dividends on common stock	(184)					(184)
Change in deferred compensation	(4)					(4)
Balance at end of period at Sep. 30, 2023	5,315		440		1,726	6,157		(3,008)
Balance at end of period (in shares) at Sep. 30, 2023				148,146
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)
Balance at beginning of period at Jun. 30, 2023	5,283		440		1,722	6,051		(2,930)
Balance at beginning of period (in shares) at Jun. 30, 2023				148,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	175					175
Other comprehensive income (loss), net of tax	(78)							(78)
Net activity under employee plans and related tax benefits (in shares)				2
Net activity under employee plans and related tax benefits	4				4
Dividends on preferred stock	(7)					(7)
Dividends on common stock	(61)					(61)
Change in deferred compensation	(1)					(1)
Balance at end of period at Sep. 30, 2023	5,315		440		1,726	6,157		(3,008)
Balance at end of period (in shares) at Sep. 30, 2023				148,146
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	5,315		440		1,726	6,157		(3,008)
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	$ 568					568
Other comprehensive income (loss), net of tax	356							356
Bank common stock repurchased (in shares)				(893)
Bank common stock repurchased	(35)				(35)
Net activity under employee plans and related tax benefits (in shares)				439
Net activity under employee plans and related tax benefits	21				21
Dividends on preferred stock	(31)					(31)
Dividends on common stock	(184)					(184)
Change in deferred compensation	(1)					(1)
Balance at end of period at Sep. 30, 2024	$ 6,385		440		1,717	6,564		(2,336)
Balance at end of period (in shares) at Sep. 30, 2024	147,699			147,699
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)
Balance at beginning of period at Jun. 30, 2024	6,025		440		1,713	6,421		(2,549)
Balance at beginning of period (in shares) at Jun. 30, 2024				147,684
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for the period	214					214
Other comprehensive income (loss), net of tax	213							213
Bank common stock repurchased (in shares)				(3)
Bank common stock repurchased	0
Net activity under employee plans and related tax benefits (in shares)				18
Net activity under employee plans and related tax benefits	4				4
Dividends on preferred stock	(10)					(10)
Dividends on common stock	(61)					(61)
Balance at end of period at Sep. 30, 2024	$ 6,385		440		1,717	6,564		(2,336)
Balance at end of period (in shares) at Sep. 30, 2024	147,699			147,699
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment, due to adoption of ASU 2022-02, net of tax	$ 6,385		$ 440		$ 1,717	$ 6,564		$ (2,336)