Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	$ 28,887	$ 29,201
Other comprehensive income (loss), net of taxes	(7,638)	(1,309)	$ 1,862
Balance, end of year	21,560	28,887	29,201
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(9,640)	(1,671)	2,352
Income tax expense (benefit)	(2,002)	(362)	490
Other comprehensive income (loss), net of taxes	(7,638)	(1,309)	1,862
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	1,193	2,502	640
Other comprehensive income (loss) before reclassifications	(7,748)	(1,337)	1,837
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	110	28	25
Other comprehensive income (loss), net of taxes	(7,638)	(1,309)	1,862
Balance, end of year	(6,445)	1,193	2,502
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(9,640)	(1,671)	2,352
Income tax expense (benefit)	(2,002)	(362)	490
Other comprehensive income (loss), net of taxes	(7,638)	(1,309)	1,862
Changes in Net Unrealized Gains (Losses) on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	2,233	3,892	2,057
Other comprehensive income (loss) before reclassifications	(7,387)	(1,606)	1,876
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	77	(53)	(41)
Other comprehensive income (loss), net of taxes	(7,310)	(1,659)	1,835
Balance, end of year	(5,077)	2,233	3,892
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(9,276)	(2,115)	2,331
Income tax expense (benefit)	(1,966)	(456)	496
Other comprehensive income (loss), net of taxes	(7,310)	(1,659)	1,835
Changes in Net Unrealized Gains (Losses) on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	182	182	189
Other comprehensive income (loss) before reclassifications	(3)	0	(7)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0	0
Other comprehensive income (loss), net of taxes	(3)	0	(7)
Balance, end of year	179	182	182
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(4)	0	(9)
Income tax expense (benefit)	(1)	0	(2)
Other comprehensive income (loss), net of taxes	(3)	0	(7)
Net Benefit Plan Assets and Obligations Recognized in Shareholders’ Equity [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	(473)	(832)	(846)
Other comprehensive income (loss) before reclassifications	(102)	278	(53)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	33	81	67
Other comprehensive income (loss), net of taxes	(69)	359	14
Balance, end of year	(542)	(473)	(832)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(87)	455	18
Income tax expense (benefit)	(18)	96	4
Other comprehensive income (loss), net of taxes	(69)	359	14
Net Unrealized Foreign Currency Translation [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of year	(749)	(740)	(760)
Other comprehensive income (loss) before reclassifications	(256)	(9)	21
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0	0	(1)
Other comprehensive income (loss), net of taxes	(256)	(9)	20
Balance, end of year	(1,005)	(749)	(740)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before income taxes	(273)	(11)	12
Income tax expense (benefit)	(17)	(2)	(8)
Other comprehensive income (loss), net of taxes	$ (256)	$ (9)	$ 20