Fair Value Measurement - Changes in Level 3 Recurring Measurements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Net derivative receivables:
Fair value, beginning balance	$ (1,814)	$ (2,278)	$ (1,852)	$ 673
Total realized/unrealized gains/(losses)	1,193	1,063	462	873
Purchases	265	284	1,120	1,113
Sales	(999)	(468)	(2,543)	(2,152)
Settlements	280	(160)	1,186	(969)
Transfers into level 3	(356)	17	(248)	(468)
Transfers (out of) level 3	19	73	463	(539)
Fair value, ending balance	(1,412)	(1,469)	(1,412)	(1,469)
Change in unrealized gains/(losses) related to financial instruments held	$ 848	959	$ 851	805
Level 3 Rollforward Supplemental Data
Level 3 assets as a percentage of total firm assets at fair value	2.00%		2.00%		2.00%
Level 3 liabilities as a percentage of total firm liabilities at fair value	7.00%		7.00%		8.00%
Deposits
Liabilities:
Fair value, beginning balance	$ 1,923	2,053	$ 1,833	2,162
Total realized/unrealized (gains)/losses	105	(34)	90	(37)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	512	341	1,304	608
Settlements	(299)	(468)	(909)	(716)
Transfers into level 3	0	0	34	0
Transfers (out of) level 3	(22)	(40)	(133)	(165)
Fair value, ending balance	2,219	1,852	2,219	1,852
Change in unrealized (gains)/losses related to financials instruments held	104	(34)	78	(41)
Short-term borrowings
Liabilities:
Fair value, beginning balance	2,726	1,704	1,758	1,401
Total realized/unrealized (gains)/losses	74	22	143	162
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	2,283	1,371	5,742	3,613
Settlements	(1,435)	(1,150)	(3,992)	(3,209)
Transfers into level 3	1	0	2	2
Transfers (out of) level 3	(2)	(2)	(6)	(24)
Fair value, ending balance	3,647	1,945	3,647	1,945
Change in unrealized (gains)/losses related to financials instruments held	56	2	78	12
Total debt and equity instruments
Liabilities:
Fair value, beginning balance	68	63	37	84
Total realized/unrealized (gains)/losses	(1)	(5)	(41)	(18)
Purchases	(20)	(2)	(26)	(29)
Sales	5	2	62	8
Issuances	0	0	0	0
Settlements	0	(2)	0	(4)
Transfers into level 3	25	0	46	18
Transfers (out of) level 3	(5)	(15)	(6)	(18)
Fair value, ending balance	72	41	72	41
Change in unrealized (gains)/losses related to financials instruments held	(1)	0	(3)	3
Accounts payable and other liabilities
Liabilities:
Fair value, beginning balance	70	68	52	53
Total realized/unrealized (gains)/losses	5	(7)	(7)	(3)
Purchases	(30)	(11)	(36)	(13)
Sales	0	13	31	20
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into level 3	0	0	5	8
Transfers (out of) level 3	(3)	0	(3)	(2)
Fair value, ending balance	42	63	42	63
Change in unrealized (gains)/losses related to financials instruments held	5	(7)	(7)	(3)
Long-term debt
Liabilities:
Fair value, beginning balance	31,286	25,425	27,726	24,092
Total realized/unrealized (gains)/losses	1,632	(764)	2,147	917
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	6,073	3,380	17,049	8,780
Settlements	(5,258)	(3,130)	(13,230)	(8,655)
Transfers into level 3	23	18	466	222
Transfers (out of) level 3	(283)	(82)	(685)	(509)
Fair value, ending balance	33,473	24,847	33,473	24,847
Change in unrealized (gains)/losses related to financials instruments held	1,783	(774)	1,895	667
DVA for fair value option elected liabilities
Level 3 Rollforward Supplemental Data
Unrealized (gains)/losses on liabilities recorded in OCI	0	0	(37)	(277)
Interest rate
Net derivative receivables:
Fair value, beginning balance	1,301	(1,122)	502	701
Total realized/unrealized gains/(losses)	1,528	(162)	1,246	(859)
Purchases	90	79	282	174
Sales	(38)	(127)	(122)	(219)
Settlements	98	349	981	376
Transfers into level 3	(106)	(56)	81	(1,135)
Transfers (out of) level 3	(44)	(72)	(141)	(149)
Fair value, ending balance	2,829	(1,111)	2,829	(1,111)
Change in unrealized gains/(losses) related to financial instruments held	1,373	(267)	892	(789)
Credit
Net derivative receivables:
Fair value, beginning balance	180	689	265	13
Total realized/unrealized gains/(losses)	(209)	11	(143)	485
Purchases	0	2	0	5
Sales	0	0	(16)	(4)
Settlements	(114)	(150)	(253)	52
Transfers into level 3	25	(4)	(13)	22
Transfers (out of) level 3	19	3	61	(22)
Fair value, ending balance	(99)	551	(99)	551
Change in unrealized gains/(losses) related to financial instruments held	(198)	11	(68)	487
Foreign exchange
Net derivative receivables:
Fair value, beginning balance	168	389	62	489
Total realized/unrealized gains/(losses)	(31)	88	100	140
Purchases	59	55	136	134
Sales	(105)	(18)	(230)	(126)
Settlements	71	(5)	(16)	(206)
Transfers into level 3	3	7	(26)	126
Transfers (out of) level 3	(125)	(3)	14	(44)
Fair value, ending balance	40	513	40	513
Change in unrealized gains/(losses) related to financial instruments held	(5)	51	105	114
Equity
Net derivative receivables:
Fair value, beginning balance	(2,991)	(1,881)	(2,402)	(384)
Total realized/unrealized gains/(losses)	(21)	1,013	(545)	1,036
Purchases	112	145	680	758
Sales	(821)	(222)	(2,020)	(1,584)
Settlements	24	(385)	246	(1,111)
Transfers into level 3	(285)	70	(296)	530
Transfers (out of) level 3	172	(39)	527	(544)
Fair value, ending balance	(3,810)	(1,299)	(3,810)	(1,299)
Change in unrealized gains/(losses) related to financial instruments held	(215)	1,060	104	936
Commodity
Net derivative receivables:
Fair value, beginning balance	(472)	(353)	(279)	(146)
Total realized/unrealized gains/(losses)	(74)	113	(196)	71
Purchases	4	3	22	42
Sales	(35)	(101)	(155)	(219)
Settlements	201	31	228	(80)
Transfers into level 3	7	0	6	(11)
Transfers (out of) level 3	(3)	184	2	220
Fair value, ending balance	(372)	(123)	(372)	(123)
Change in unrealized gains/(losses) related to financial instruments held	(107)	104	(182)	57
Federal funds sold and securities purchased under resale agreements
Assets:
Fair value, beginning balance	0	0	0	0
Total realized/unrealized gains/(losses)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	0	0	0
Fair value, ending balance	0	0	0	0
Change in unrealized gains/(losses) related to financial instruments held	0	0	0	0
Total mortgage-backed securities
Assets:
Fair value, beginning balance	724	717	775	771
Total realized/unrealized gains/(losses)	4	2	2	16
Purchases	0	119	46	250
Sales	0	(20)	(61)	(139)
Settlements	(21)	(21)	(62)	(88)
Transfers into level 3	0	0	11	9
Transfers (out of) level 3	0	0	(4)	(22)
Fair value, ending balance	707	797	707	797
Change in unrealized gains/(losses) related to financial instruments held	3	3	1	8
Mortgage-backed securities, U.S. GSEs and government agencies
Assets:
Fair value, beginning balance	708	706	758	759
Total realized/unrealized gains/(losses)	3	(4)	3	3
Purchases	0	118	45	249
Sales	0	(20)	(61)	(133)
Settlements	(20)	(21)	(61)	(85)
Transfers into level 3	0	0	7	0
Transfers (out of) level 3	0	0	0	(14)
Fair value, ending balance	691	779	691	779
Change in unrealized gains/(losses) related to financial instruments held	3	(4)	3	3
Mortgage-backed securities, Residential - nonagency
Assets:
Fair value, beginning balance	5	5	5	5
Total realized/unrealized gains/(losses)	1	0	1	7
Purchases	0	0	0	0
Sales	0	0	0	(6)
Settlements	(1)	0	(1)	(2)
Transfers into level 3	0	0	4	1
Transfers (out of) level 3	0	0	(4)	0
Fair value, ending balance	5	5	5	5
Change in unrealized gains/(losses) related to financial instruments held	0	0	(1)	0
Mortgage-backed securities, Commercial - nonagency
Assets:
Fair value, beginning balance	11	6	12	7
Total realized/unrealized gains/(losses)	0	6	(2)	6
Purchases	0	1	1	1
Sales	0	0	0	0
Settlements	0	0	0	(1)
Transfers into level 3	0	0	0	8
Transfers (out of) level 3	0	0	0	(8)
Fair value, ending balance	11	13	11	13
Change in unrealized gains/(losses) related to financial instruments held	0	7	(1)	5
Total debt and equity instruments
Assets:
Fair value, beginning balance	2,301	3,313	2,373	2,909
Total realized/unrealized gains/(losses)	49	(32)	91	(39)
Purchases	284	523	1,204	1,761
Sales	(253)	(409)	(969)	(922)
Settlements	(53)	(491)	(375)	(680)
Transfers into level 3	388	160	789	470
Transfers (out of) level 3	(279)	(142)	(676)	(577)
Fair value, ending balance	2,437	2,922	2,437	2,922
Change in unrealized gains/(losses) related to financial instruments held	56	(27)	80	51
Total debt instruments
Assets:
Fair value, beginning balance	2,025	2,563	2,138	2,178
Total realized/unrealized gains/(losses)	33	(29)	48	51
Purchases	264	487	1,024	1,515
Sales	(235)	(309)	(870)	(715)
Settlements	(43)	(34)	(319)	(217)
Transfers into level 3	333	119	690	288
Transfers (out of) level 3	(234)	(134)	(568)	(437)
Fair value, ending balance	2,143	2,663	2,143	2,663
Change in unrealized gains/(losses) related to financial instruments held	33	(30)	40	99
Obligations of U.S. states and municipalities
Assets:
Fair value, beginning balance	7	6	10	7
Total realized/unrealized gains/(losses)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	(1)
Settlements	0	0	(2)	0
Transfers into level 3	0	3	0	3
Transfers (out of) level 3	0	0	(1)	0
Fair value, ending balance	7	9	7	9
Change in unrealized gains/(losses) related to financial instruments held	0	0	0	0
Non-U.S. government debt securities
Assets:
Fair value, beginning balance	193	199	179	155
Total realized/unrealized gains/(losses)	(4)	9	(2)	49
Purchases	53	16	145	116
Sales	(65)	(53)	(137)	(149)
Settlements	0	0	0	0
Transfers into level 3	7	0	14	0
Transfers (out of) level 3	(11)	(20)	(26)	(20)
Fair value, ending balance	173	151	173	151
Change in unrealized gains/(losses) related to financial instruments held	(2)	18	4	86
Corporate debt securities
Assets:
Fair value, beginning balance	408	522	484	463
Total realized/unrealized gains/(losses)	21	15	28	39
Purchases	86	191	386	301
Sales	(62)	(56)	(229)	(116)
Settlements	0	(1)	(181)	(3)
Transfers into level 3	5	8	13	38
Transfers (out of) level 3	(23)	(27)	(66)	(70)
Fair value, ending balance	435	652	435	652
Change in unrealized gains/(losses) related to financial instruments held	20	4	27	34
Loans
Assets:
Fair value, beginning balance	691	1,105	684	759
Total realized/unrealized gains/(losses)	12	(56)	20	(54)
Purchases	125	161	446	843
Sales	(108)	(172)	(438)	(299)
Settlements	(22)	(12)	(67)	(125)
Transfers into level 3	321	108	645	233
Transfers (out of) level 3	(200)	(86)	(471)	(309)
Fair value, ending balance	819	1,048	819	1,048
Change in unrealized gains/(losses) related to financial instruments held	12	(56)	8	(28)
Asset-backed securities
Assets:
Fair value, beginning balance	2	14	6	23
Total realized/unrealized gains/(losses)	0	1	0	1
Purchases	0	0	1	5
Sales	0	(8)	(5)	(11)
Settlements	0	0	(7)	(1)
Transfers into level 3	0	0	7	5
Transfers (out of) level 3	0	(1)	0	(16)
Fair value, ending balance	2	6	2	6
Change in unrealized gains/(losses) related to financial instruments held	0	1	0	(1)
Equity securities
Assets:
Fair value, beginning balance	122	631	127	665
Total realized/unrealized gains/(losses)	(4)	2	(23)	(45)
Purchases	16	26	130	134
Sales	(18)	(100)	(99)	(207)
Settlements	(1)	(442)	(1)	(442)
Transfers into level 3	31	41	74	181
Transfers (out of) level 3	(45)	(7)	(107)	(135)
Fair value, ending balance	101	151	101	151
Change in unrealized gains/(losses) related to financial instruments held	0	7	(33)	(28)
Physical commodities
Assets:
Fair value, beginning balance	10	6	7	2
Total realized/unrealized gains/(losses)	0	(2)	2	(2)
Purchases	0	1	4	7
Sales	0	0	0	0
Settlements	0	0	(3)	(2)
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	0	0	0
Fair value, ending balance	10	5	10	5
Change in unrealized gains/(losses) related to financial instruments held	0	(2)	2	5
Other
Assets:
Fair value, beginning balance	144	113	101	64
Total realized/unrealized gains/(losses)	20	(3)	64	(43)
Purchases	4	9	46	105
Sales	0	0	0	0
Settlements	(9)	(15)	(52)	(19)
Transfers into level 3	24	0	25	1
Transfers (out of) level 3	0	(1)	(1)	(5)
Fair value, ending balance	183	103	183	103
Change in unrealized gains/(losses) related to financial instruments held	23	(2)	71	(25)
Total available-for-sale securities
Assets:
Fair value, beginning balance	0	267	0	239
Total realized/unrealized gains/(losses)	0	(4)	0	24
Purchases	0	0	0	0
Sales	0	(165)	0	(165)
Settlements	0	0	0	0
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	(38)	0	(38)
Fair value, ending balance	0	60	0	60
Change in unrealized gains/(losses) related to financial instruments held	0	(3)	0	22
Corporate debt securities
Assets:
Fair value, beginning balance	0	267	0	239
Total realized/unrealized gains/(losses)	0	(4)	0	24
Purchases	0	0	0	0
Sales	0	(165)	0	(165)
Settlements	0	0	0	0
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	(38)	0	(38)
Fair value, ending balance	0	60	0	60
Change in unrealized gains/(losses) related to financial instruments held	0	(3)	0	22
Loans
Assets:
Fair value, beginning balance	2,993	3,808	3,079	1,418
Total realized/unrealized gains/(losses)	157	110	266	133
Purchases	95	24	304	2,309
Sales	(479)	(34)	(684)	(107)
Settlements	(210)	(442)	(855)	(1,027)
Transfers into level 3	61	276	730	1,193
Transfers (out of) level 3	(130)	(59)	(353)	(236)
Fair value, ending balance	2,487	3,683	2,487	3,683
Change in unrealized gains/(losses) related to financial instruments held	114	25	207	29
Mortgage servicing rights
Assets:
Fair value, beginning balance	8,847	8,229	8,522	7,973
Total realized/unrealized gains/(losses)	(181)	596	216	860
Purchases	357	650	835	1,227
Sales	2	(101)	(25)	(191)
Settlements	(272)	(265)	(795)	(760)
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	0	0	0
Fair value, ending balance	8,753	9,109	8,753	9,109
Change in unrealized gains/(losses) related to financial instruments held	(181)	596	216	860
Other assets
Assets:
Fair value, beginning balance	1,202	417	758	405
Total realized/unrealized gains/(losses)	34	(1)	100	20
Purchases	24	498	444	515
Sales	(32)	(11)	(54)	(13)
Settlements	(20)	(14)	(45)	(44)
Transfers into level 3	0	0	5	8
Transfers (out of) level 3	(22)	(1)	(22)	(3)
Fair value, ending balance	1,186	888	1,186	888
Change in unrealized gains/(losses) related to financial instruments held	$ 34	$ (1)	$ 94	$ 56