Fair Value, Assets and Liabilities, Changes in Level 3 Fair Value Assets and Liabilities on a Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Trading debt securities [Member]
Assets:
Balance, beginning of period	$ 169	$ 241	$ 192	$ 241	$ 173
Net gains (losses)	(15)		1	(52)	21
Purchases	68		130	161	422
Sales	(43)		(101)	(135)	(403)
Settlements	0		(2)	(6)	(7)
Transfers into Level 3	0		0	5	22
Transfers out of Level 3	3		(6)	(32)	(14)
Balance, end of period	182		214	182	214
Net unrealized gains (losses) related to assets and liabilities held at period end	(15)		(3)	(48)	2
Available-for-sale debt securities [Member]
Assets:
Balance, beginning of period	167	186	2,805	186	2,994
Net gains (losses)	(9)		1	(35)	22
Purchases	225		362	279	386
Sales	0		0	(25)	0
Settlements	(4)		(49)	(14)	(237)
Transfers into Level 3	334		0	460	253
Transfers out of Level 3	0		(816)	(138)	(1,115)
Balance, end of period	713		2,303	713	2,303
Net unrealized gains (losses) related to assets and liabilities held at period end	0		7	(1)	(13)
Fair Value Disclosures, Textual [Abstract]
Total net gains (losses) included in other comprehensive income	(9)		(2)	(36)	34
Net unrealized gains (losses) related to assets and liabilities held at period end and included in other comprehensive income			5		(3)
Loans held for sale [Member]
Assets:
Balance, beginning of period	1,072	1,033	1,069	1,033	1,234
Net gains (losses)	(55)		(8)	(173)	(12)
Purchases	114		117	293	377
Sales	(36)		(79)	(106)	(458)
Settlements	(45)		(83)	(175)	(300)
Transfers into Level 3	28		106	214	284
Transfers out of Level 3	(4)		(131)	(12)	(134)
Balance, end of period	1,074		991	1,074	991
Net unrealized gains (losses) related to assets and liabilities held at period end	(55)		(10)	(163)	(13)
Mortgage servicing rights [Member] | Residential mortgage [Member]
Assets:
Balance, beginning of period	9,163	6,920	6,717	6,920	6,125
Net gains (losses)	460		(232)	2,289	(523)
Purchases	204		379	868	1,270
Sales	1		(2)	(249)	(10)
Settlements	0		0	0	0
Transfers into Level 3	0		0	0	0
Transfers out of Level 3	0		0	0	0
Balance, end of period	9,828		6,862	9,828	6,862
Net unrealized gains (losses) related to assets and liabilities held at period end	750		275	3,223	1,057
Derivative [Member]
Assets and Liabilities:
Balance, beginning of period	(1,937)	(297)	(76)	(297)	171
Net gains (losses)	(2,329)		(451)	(3,243)	(900)
Purchases	13		1	13	3
Sales	(8)		(3)	(8)	(4)
Settlements	409		360	1,996	508
Transfers into Level 3	200		(60)	(781)	(97)
Transfers out of Level 3	242		46	(1,090)	136
Balance, end of period	(3,410)		(183)	(3,410)	(183)
Net unrealized gains (losses) related to assets and liabilities held at period end	(1,704)		36	(1,666)	(178)
Derivative [Member] | Interest rate contracts [Member]
Assets and Liabilities:
Balance, beginning of period	(571)	127	314	127	446
Net gains (losses)	(2,220)		110	(3,179)	27
Purchases	0		0	0	0
Sales	0		0	0	0
Settlements	132		(260)	778	(304)
Transfers into Level 3	188		0	(197)	0
Transfers out of Level 3	1		0	1	(5)
Balance, end of period	(2,470)		164	(2,470)	164
Net unrealized gains (losses) related to assets and liabilities held at period end	(1,905)		16	(2,348)	(14)
Derivative [Member] | Equity contracts [Member]
Assets and Liabilities:
Balance, beginning of period	(1,503)	(429)	(425)	(429)	(314)
Net gains (losses)	(137)		(493)	(158)	(819)
Purchases	0		0	0	0
Sales	0		0	0	0
Settlements	249		595	1,118	755
Transfers into Level 3	12		(58)	(584)	(95)
Transfers out of Level 3	236		46	(1,090)	138
Balance, end of period	(1,143)		(335)	(1,143)	(335)
Net unrealized gains (losses) related to assets and liabilities held at period end	131		45	503	(154)
Derivative [Member] | Equity contracts [Member] | Nonmarketable equity securities [Member]
Assets and Liabilities:
Transfers out of Level 3		1,400
Derivative [Member] | Other contract [Member]
Assets and Liabilities:
Balance, beginning of period	137	5	35	5	39
Net gains (losses)	28		(68)	94	(108)
Purchases	13		1	13	3
Sales	(8)		(3)	(8)	(4)
Settlements	28		25	100	57
Transfers into Level 3	0		(2)	0	(2)
Transfers out of Level 3	5		0	(1)	3
Balance, end of period	203		(12)	203	(12)
Net unrealized gains (losses) related to assets and liabilities held at period end	70		(25)	179	(10)
Securities [Member] | Equity securities [Member]
Assets:
Balance, beginning of period	31	8,910	9,660	8,910	9,233
Net gains (losses)	(1)		(487)	3	(58)
Purchases	1		0	1	0
Sales	(1)		0	(3)	(5)
Settlements	0		0	0	0
Transfers into Level 3	(3)		4	2	7
Transfers out of Level 3	(9)		0	(8,895)	0
Balance, end of period	18		9,177	18	9,177
Net unrealized gains (losses) related to assets and liabilities held at period end	$ (1)		$ (487)	$ (2)	$ (59)
Securities [Member] | Nonmarketable equity securities [Member]
Assets:
Transfers out of Level 3		$ 8,900