Fair Values - Activity of Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - Level 3 - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Liabilities at Fair Value
Portion of Unrealized losses (gains) recorded in OCI—Change in net DVA	$ (36)	$ (4)		$ (126)	$ (18)
Deposits
Liabilities at Fair Value
Beginning balance	19	86	$ 126	67	126
Realized and unrealized losses (gains)	0	(1)		0	1
Issuances	2	0		2	0
Settlements	(1)	(4)		(3)	(12)
Net transfers	(13)	(19)		(59)	(53)
Ending balance	7	62	86	7	62
Unrealized losses (gains)	0	(1)		0	1
Nonderivative trading liabilities
Liabilities at Fair Value
Beginning balance	104	59	79	61	79
Realized and unrealized losses (gains)	(8)	(11)		(41)	(20)
Purchases	(20)	(16)		(39)	(88)
Sales	16	11		88	83
Net transfers	(2)	(1)		21	(12)
Ending balance	90	42	59	90	42
Unrealized losses (gains)	(8)	(11)		(41)	1
Securities sold under agreements to repurchase
Liabilities at Fair Value
Beginning balance	514	449	444	651	444
Realized and unrealized losses (gains)	5	(1)		(3)	5
Issuances	0	0		9	0
Settlements	(11)	0		(22)	0
Net transfers	0	0		(127)	(1)
Ending balance	508	448	449	508	448
Unrealized losses (gains)	5	(1)		0	5
Other secured financings
Liabilities at Fair Value
Beginning balance	112	401	516	403	516
Realized and unrealized losses (gains)	(5)	(17)		(11)	(14)
Issuances	13	14		44	421
Settlements	(7)	(3)		(320)	(500)
Net transfers	0	0		(3)	(28)
Ending balance	113	395	401	113	395
Unrealized losses (gains)	(5)	(17)		(11)	(13)
Borrowings
Liabilities at Fair Value
Beginning balance	2,325	1,975	4,374	2,157	4,374
Realized and unrealized losses (gains)	(185)	(87)		(625)	(37)
Issuances	65	197		230	411
Settlements	(65)	(67)		(263)	(347)
Net transfers	(203)	38		438	(2,345)
Ending balance	1,937	2,056	1,975	1,937	2,056
Unrealized losses (gains)	(185)	(86)		(629)	(8)
Net derivatives: Interest rate
Assets at Fair value
Beginning balance	(102)	668	682	708	682
Realized and unrealized gains (losses)	(200)	70		(482)	(223)
Purchases	0	22		0	48
Issuances	0	(9)		0	(41)
Settlements	122	18		(38)	101
Net transfers	3	27		(365)	229
Ending balance	(177)	796	668	(177)	796
Unrealized gains (losses)	(120)	165		(201)	(168)
Net derivatives: Credit
Assets at Fair value
Beginning balance	190	(203)	49	98	49
Realized and unrealized gains (losses)	3	59		91	(2)
Purchases	0	12		3	23
Issuances	0	(19)		(1)	(44)
Settlements	(78)	102		(59)	16
Net transfers	7	15		(10)	(76)
Ending balance	122	(34)	(203)	122	(34)
Unrealized gains (losses)	7	(26)		83	0
Net derivatives: Foreign exchange
Assets at Fair value
Beginning balance	(331)	33	61	52	61
Realized and unrealized gains (losses)	38	32		(18)	41
Purchases	0	12		0	19
Issuances	0	(15)		0	(21)
Settlements	73	46		47	(45)
Net transfers	395	(11)		94	42
Ending balance	175	97	33	175	97
Unrealized gains (losses)	44	29		18	73
Net derivatives: Equity
Assets at Fair value
Beginning balance	(530)	(837)	(2,231)	(945)	(2,231)
Realized and unrealized gains (losses)	1	(45)		275	366
Purchases	48	24		167	69
Issuances	(92)	(122)		(253)	(362)
Settlements	68	(3)		379	(196)
Net transfers	49	(17)		(79)	1,354
Ending balance	(456)	(1,000)	(837)	(456)	(1,000)
Unrealized gains (losses)	(3)	(96)		399	(57)
Net derivatives: Commodity and other
Assets at Fair value
Beginning balance	1,344	1,430	1,709	1,529	1,709
Realized and unrealized gains (losses)	238	(167)		546	43
Purchases	2	44		107	324
Issuances	(7)	(31)		(97)	(137)
Settlements	69	(97)		(247)	(371)
Net transfers	155	130		(37)	(259)
Ending balance	1,801	1,309	1,430	1,801	1,309
Unrealized gains (losses)	72	(96)		25	(243)
U.S. Treasury and agency securities
Assets at Fair value
Beginning balance	9	25	9	2	9
Realized and unrealized gains (losses)	0	(1)		(1)	0
Purchases	1	4		2	28
Sales	(4)	(24)		(7)	(33)
Net transfers	(5)	0		5	0
Ending balance	1	4	25	1	4
Unrealized gains (losses)	0	(1)		(1)	0
Other sovereign government obligations
Assets at Fair value
Beginning balance	161	78	268	211	268
Realized and unrealized gains (losses)	23	(3)		(24)	(1)
Purchases	43	59		69	129
Sales	(57)	(4)		(60)	(269)
Net transfers	(33)	(3)		(59)	0
Ending balance	137	127	78	137	127
Unrealized gains (losses)	23	(3)		(22)	0
State and municipal securities
Assets at Fair value
Beginning balance	29	4	0	13	0
Realized and unrealized gains (losses)	(1)	0		(2)	0
Purchases	4	0		54	4
Sales	0	(4)		0	(4)
Net transfers	20	0		(13)	0
Ending balance	52	0	4	52	0
Unrealized gains (losses)	(3)	0		(2)	0
MABS
Assets at Fair value
Beginning balance	339	357	322	344	322
Realized and unrealized gains (losses)	8	11		(366)	67
Purchases	3	96		448	263
Sales	(33)	(23)		(116)	(216)
Net transfers	27	(75)		34	(70)
Ending balance	344	366	357	344	366
Unrealized gains (losses)	9	11		(12)	8
Loans and lending commitments
Assets at Fair value
Beginning balance	2,507	4,896	5,759	3,806	5,759
Realized and unrealized gains (losses)	(26)	47		8	33
Purchases and originations	541	1,373		800	2,467
Sales	(353)	(768)		(801)	(2,314)
Settlements	(144)	(414)		(618)	(1,082)
Net transfers	58	(830)		(612)	(559)
Ending balance	2,583	4,304	4,896	2,583	4,304
Unrealized gains (losses)	(27)	21		0	(5)
Liabilities at Fair Value
Transfers from Level 3 to Level 2		895
Corporate and other debt
Assets at Fair value
Beginning balance	2,113	1,801	3,435	1,973	3,435
Realized and unrealized gains (losses)	(43)	173		446	(151)
Purchases and originations	132	639		752	1,505
Sales	(528)	(594)		(1,400)	(1,698)
Settlements	(30)	0		(26)	0
Net transfers	254	(456)		153	(1,528)
Ending balance	1,898	1,563	1,801	1,898	1,563
Unrealized gains (losses)	(42)	173		454	10
Liabilities at Fair Value
Transfers from Level 3 to Level 2		2,000
Corporate equities
Assets at Fair value
Beginning balance	246	150	86	115	86
Realized and unrealized gains (losses)	(60)	4		(71)	(15)
Purchases	15	83		79	367
Sales	(37)	(7)		(67)	(193)
Net transfers	(19)	(16)		89	(31)
Ending balance	145	214	150	145	214
Unrealized gains (losses)	(60)	4		(65)	(5)
Investments
Assets at Fair value
Beginning balance	1,027	978	828	1,125	828
Realized and unrealized gains (losses)	(140)	18		(275)	58
Purchases	6	59		52	150
Sales	(18)	(23)		(33)	(46)
Net transfers	(2)	(251)		4	(209)
Ending balance	873	781	978	873	781
Unrealized gains (losses)	(136)	13		(267)	39
Investment securities —AFS
Assets at Fair value
Beginning balance	38	0	2,804	0	2,804
Realized and unrealized gains (losses)	(2)	0		(2)	(4)
Sales	0	0		0	(203)
Net transfers	0	0		38	(2,597)
Ending balance	36	0	0	36	0
Unrealized gains (losses)	$ (2)	0		$ (2)	$ 0
Liabilities at Fair Value
Transfers from Level 3 to Level 2			$ 2,500
Net derivatives: Equity
Liabilities at Fair Value
Transfers from Level 3 to Level 2		1,000
Borrowings
Liabilities at Fair Value
Transfers from Level 3 to Level 2		$ 2,200