Fair Value Measurement - Changes in Level 3 Recurring Measurements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Net derivative receivables:
Fair value, beginning balance	$ (2,200)	$ 579	$ (1,852)	$ 673
Total realized/unrealized gains/(losses)	447	(1,050)	(731)	(190)
Purchases	437	441	855	829
Sales	(772)	(836)	(1,544)	(1,684)
Settlements	192	(756)	906	(809)
Transfers into level 3	85	(520)	108	(485)
Transfers (out of) level 3	(3)	(136)	444	(612)
Fair value, ending balance	(1,814)	(2,278)	(1,814)	(2,278)
Change in unrealized gains/(losses) related to financial instruments held	$ 529	(811)	$ (156)	(167)
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	6.00%		6.00%		8.00%
Deposits
Liabilities:
Fair value, beginning balance	$ 2,055	2,208	$ 1,833	2,162
Total realized/unrealized (gains)/losses	14	(51)	(15)	(3)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	265	139	792	267
Settlements	(407)	(181)	(610)	(248)
Transfers into level 3	34	0	34	0
Transfers (out of) level 3	(38)	(62)	(111)	(125)
Fair value, ending balance	1,923	2,053	1,923	2,053
Change in unrealized (gains)/losses related to financials instruments held	12	(51)	(21)	(31)
Short-term borrowings
Liabilities:
Fair value, beginning balance	2,206	1,410	1,758	1,401
Total realized/unrealized (gains)/losses	68	50	69	140
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	1,814	1,191	3,459	2,242
Settlements	(1,360)	(927)	(2,557)	(2,059)
Transfers into level 3	1	2	1	2
Transfers (out of) level 3	(3)	(22)	(4)	(22)
Fair value, ending balance	2,726	1,704	2,726	1,704
Change in unrealized (gains)/losses related to financials instruments held	45	29	30	34
Total debt and equity instruments
Liabilities:
Fair value, beginning balance	37	63	37	84
Total realized/unrealized (gains)/losses	(37)	(1)	(40)	(13)
Purchases	(5)	0	(6)	(27)
Sales	55	(2)	57	6
Issuances	0	0	0	0
Settlements	0	(2)	0	(2)
Transfers into level 3	18	6	21	18
Transfers (out of) level 3	0	(1)	(1)	(3)
Fair value, ending balance	68	63	68	63
Change in unrealized (gains)/losses related to financials instruments held	(37)	(1)	(67)	0
Accounts payable and other liabilities
Liabilities:
Fair value, beginning balance	48	56	52	53
Total realized/unrealized (gains)/losses	(8)	5	(12)	4
Purchases	(3)	(2)	(6)	(2)
Sales	28	3	31	7
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into level 3	5	8	5	8
Transfers (out of) level 3	0	(2)	0	(2)
Fair value, ending balance	70	68	70	68
Change in unrealized (gains)/losses related to financials instruments held	(8)	5	(12)	4
Long-term debt
Liabilities:
Fair value, beginning balance	28,678	25,227	27,726	24,092
Total realized/unrealized (gains)/losses	(36)	325	515	1,681
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	6,473	2,667	10,976	5,400
Settlements	(4,121)	(2,550)	(7,972)	(5,525)
Transfers into level 3	426	113	443	204
Transfers (out of) level 3	(134)	(357)	(402)	(427)
Fair value, ending balance	31,286	25,425	31,286	25,425
Change in unrealized (gains)/losses related to financials instruments held	(31)	354	424	1,674
DVA for fair value option elected liabilities
Level 3 Rollforward Supplemental Data
Unrealized (gains)/losses on liabilities recorded in OCI	(137)	23	(97)	(277)
Interest rate
Net derivative receivables:
Fair value, beginning balance	800	754	502	701
Total realized/unrealized gains/(losses)	46	(1,043)	(282)	(697)
Purchases	139	60	192	95
Sales	(41)	(42)	(84)	(92)
Settlements	399	49	883	27
Transfers into level 3	58	(914)	187	(1,079)
Transfers (out of) level 3	(100)	14	(97)	(77)
Fair value, ending balance	1,301	(1,122)	1,301	(1,122)
Change in unrealized gains/(losses) related to financial instruments held	24	(960)	(374)	(582)
Credit
Net derivative receivables:
Fair value, beginning balance	260	452	265	13
Total realized/unrealized gains/(losses)	91	228	66	474
Purchases	0	0	0	3
Sales	(1)	(1)	(16)	(4)
Settlements	(153)	31	(139)	202
Transfers into level 3	(32)	2	(38)	26
Transfers (out of) level 3	15	(23)	42	(25)
Fair value, ending balance	180	689	180	689
Change in unrealized gains/(losses) related to financial instruments held	89	240	208	497
Foreign exchange
Net derivative receivables:
Fair value, beginning balance	24	545	62	489
Total realized/unrealized gains/(losses)	128	(37)	131	52
Purchases	43	51	77	79
Sales	(87)	(67)	(125)	(108)
Settlements	35	(126)	(87)	(201)
Transfers into level 3	24	55	(29)	119
Transfers (out of) level 3	1	(32)	139	(41)
Fair value, ending balance	168	389	168	389
Change in unrealized gains/(losses) related to financial instruments held	140	(29)	139	29
Equity
Net derivative receivables:
Fair value, beginning balance	(2,781)	(885)	(2,402)	(384)
Total realized/unrealized gains/(losses)	128	(148)	(524)	23
Purchases	247	295	568	613
Sales	(591)	(675)	(1,199)	(1,362)
Settlements	(109)	(726)	222	(726)
Transfers into level 3	38	349	(11)	460
Transfers (out of) level 3	77	(91)	355	(505)
Fair value, ending balance	(2,991)	(1,881)	(2,991)	(1,881)
Change in unrealized gains/(losses) related to financial instruments held	216	9	(6)	95
Commodity
Net derivative receivables:
Fair value, beginning balance	(503)	(287)	(279)	(146)
Total realized/unrealized gains/(losses)	54	(50)	(122)	(42)
Purchases	8	35	18	39
Sales	(52)	(51)	(120)	(118)
Settlements	20	16	27	(111)
Transfers into level 3	(3)	(12)	(1)	(11)
Transfers (out of) level 3	4	(4)	5	36
Fair value, ending balance	(472)	(353)	(472)	(353)
Change in unrealized gains/(losses) related to financial instruments held	60	(71)	(123)	(206)
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	749	772	775	771
Total realized/unrealized gains/(losses)	(1)	5	(2)	14
Purchases	44	106	46	131
Sales	(44)	(112)	(61)	(119)
Settlements	(20)	(40)	(41)	(67)
Transfers into level 3	0	5	11	9
Transfers (out of) level 3	(4)	(19)	(4)	(22)
Fair value, ending balance	724	717	724	717
Change in unrealized gains/(losses) related to financial instruments held	(1)	(7)	(1)	2
Mortgage-backed securities, U.S. GSEs and government agencies
Assets:
Fair value, beginning balance	729	757	758	759
Total realized/unrealized gains/(losses)	(1)	0	0	7
Purchases	44	106	45	131
Sales	(44)	(106)	(61)	(113)
Settlements	(20)	(40)	(41)	(64)
Transfers into level 3	0	0	7	0
Transfers (out of) level 3	0	(11)	0	(14)
Fair value, ending balance	708	706	708	706
Change in unrealized gains/(losses) related to financial instruments held	(1)	(6)	0	2
Mortgage-backed securities, Residential - nonagency
Assets:
Fair value, beginning balance	8	5	5	5
Total realized/unrealized gains/(losses)	1	6	0	7
Purchases	0	0	0	0
Sales	0	(6)	0	(6)
Settlements	0	0	0	(2)
Transfers into level 3	0	0	4	1
Transfers (out of) level 3	(4)	0	(4)	0
Fair value, ending balance	5	5	5	5
Change in unrealized gains/(losses) related to financial instruments held	1	0	0	1
Mortgage-backed securities, Commercial - nonagency
Assets:
Fair value, beginning balance	12	10	12	7
Total realized/unrealized gains/(losses)	(1)	(1)	(2)	0
Purchases	0	0	1	0
Sales	0	0	0	0
Settlements	0	0	0	(1)
Transfers into level 3	0	5	0	8
Transfers (out of) level 3	0	(8)	0	(8)
Fair value, ending balance	11	6	11	6
Change in unrealized gains/(losses) related to financial instruments held	(1)	(1)	(1)	(1)
Total debt and equity instruments
Assets:
Fair value, beginning balance	2,356	3,139	2,373	2,909
Total realized/unrealized gains/(losses)	7	(7)	42	(7)
Purchases	401	525	920	1,238
Sales	(308)	(306)	(716)	(513)
Settlements	(203)	(66)	(322)	(189)
Transfers into level 3	286	222	401	310
Transfers (out of) level 3	(238)	(194)	(397)	(435)
Fair value, ending balance	2,301	3,313	2,301	3,313
Change in unrealized gains/(losses) related to financial instruments held	33	(18)	54	17
Total debt instruments
Assets:
Fair value, beginning balance	2,044	2,418	2,138	2,178
Total realized/unrealized gains/(losses)	(5)	28	15	80
Purchases	349	467	760	1,028
Sales	(257)	(270)	(635)	(406)
Settlements	(192)	(60)	(276)	(183)
Transfers into level 3	266	118	357	169
Transfers (out of) level 3	(180)	(138)	(334)	(303)
Fair value, ending balance	2,025	2,563	2,025	2,563
Change in unrealized gains/(losses) related to financial instruments held	(8)	16	5	63
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	0	0	0
Transfers (out of) level 3	0	0	(1)	0
Fair value, ending balance	7	6	7	6
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	173	169	179	155
Total realized/unrealized gains/(losses)	(3)	29	2	40
Purchases	41	50	92	100
Sales	(5)	(49)	(72)	(96)
Settlements	0	0	0	0
Transfers into level 3	0	0	7	0
Transfers (out of) level 3	(13)	0	(15)	0
Fair value, ending balance	193	199	193	199
Change in unrealized gains/(losses) related to financial instruments held	(4)	31	(6)	43
Corporate debt securities
Assets:
Fair value, beginning balance	570	538	484	463
Total realized/unrealized gains/(losses)	(4)	0	7	24
Purchases	86	61	300	110
Sales	(72)	(43)	(167)	(60)
Settlements	(151)	(2)	(181)	(2)
Transfers into level 3	4	7	8	30
Transfers (out of) level 3	(25)	(39)	(43)	(43)
Fair value, ending balance	408	522	408	522
Change in unrealized gains/(losses) related to financial instruments held	(5)	(2)	7	18
Loans
Assets:
Fair value, beginning balance	531	926	684	759
Total realized/unrealized gains/(losses)	3	(6)	8	2
Purchases	178	246	321	682
Sales	(131)	(65)	(330)	(127)
Settlements	(14)	(18)	(45)	(113)
Transfers into level 3	262	102	324	125
Transfers (out of) level 3	(138)	(80)	(271)	(223)
Fair value, ending balance	691	1,105	691	1,105
Change in unrealized gains/(losses) related to financial instruments held	2	(6)	5	1
Asset-backed securities
Assets:
Fair value, beginning balance	14	7	6	23
Total realized/unrealized gains/(losses)	0	0	0	0
Purchases	0	4	1	5
Sales	(5)	(1)	(5)	(3)
Settlements	(7)	0	(7)	(1)
Transfers into level 3	0	4	7	5
Transfers (out of) level 3	0	0	0	(15)
Fair value, ending balance	2	14	2	14
Change in unrealized gains/(losses) related to financial instruments held	0	0	0	(1)
Equity securities
Assets:
Fair value, beginning balance	203	581	127	665
Total realized/unrealized gains/(losses)	(25)	(16)	(19)	(47)
Purchases	33	50	114	108
Sales	(51)	(36)	(81)	(107)
Settlements	0	0	0	0
Transfers into level 3	19	104	43	140
Transfers (out of) level 3	(57)	(52)	(62)	(128)
Fair value, ending balance	122	631	122	631
Change in unrealized gains/(losses) related to financial instruments held	3	(16)	5	(27)
Physical commodities
Assets:
Fair value, beginning balance	2	0	7	2
Total realized/unrealized gains/(losses)	4	0	2	0
Purchases	4	6	4	6
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	6	10	6
Change in unrealized gains/(losses) related to financial instruments held	4	0	2	0
Other
Assets:
Fair value, beginning balance	107	140	101	64
Total realized/unrealized gains/(losses)	33	(19)	44	(40)
Purchases	15	2	42	96
Sales	0	0	0	0
Settlements	(11)	(6)	(43)	(4)
Transfers into level 3	1	0	1	1
Transfers (out of) level 3	(1)	(4)	(1)	(4)
Fair value, ending balance	144	113	144	113
Change in unrealized gains/(losses) related to financial instruments held	34	(18)	42	(19)
Total available-for-sale securities
Assets:
Fair value, beginning balance	0	250	0	239
Total realized/unrealized gains/(losses)	0	17	0	28
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	267	0	267
Change in unrealized gains/(losses) related to financial instruments held	0	17	0	28
Corporate debt securities
Assets:
Fair value, beginning balance	0	250	0	239
Total realized/unrealized gains/(losses)	0	17	0	28
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	267	0	267
Change in unrealized gains/(losses) related to financial instruments held	0	17	0	28
Loans
Assets:
Fair value, beginning balance	2,901	1,479	3,079	1,418
Total realized/unrealized gains/(losses)	72	(3)	109	23
Purchases	149	2,137	209	2,285
Sales	(183)	(7)	(205)	(73)
Settlements	(253)	(490)	(645)	(585)
Transfers into level 3	366	760	669	917
Transfers (out of) level 3	(59)	(68)	(223)	(177)
Fair value, ending balance	2,993	3,808	2,993	3,808
Change in unrealized gains/(losses) related to financial instruments held	58	(52)	(3)	24
Mortgage servicing rights
Assets:
Fair value, beginning balance	8,605	7,755	8,522	7,973
Total realized/unrealized gains/(losses)	119	275	397	264
Purchases	418	546	478	577
Sales	(32)	(92)	(27)	(90)
Settlements	(263)	(255)	(523)	(495)
Transfers into level 3	0	0	0	0
Transfers (out of) level 3	0	0	0	0
Fair value, ending balance	8,847	8,229	8,847	8,229
Change in unrealized gains/(losses) related to financial instruments held	119	275	397	264
Other assets
Assets:
Fair value, beginning balance	811	406	758	405
Total realized/unrealized gains/(losses)	37	16	66	21
Purchases	373	5	420	17
Sales	(13)	(2)	(22)	(2)
Settlements	(11)	(14)	(25)	(30)
Transfers into level 3	5	8	5	8
Transfers (out of) level 3	0	(2)	0	(2)
Fair value, ending balance	1,202	417	1,202	417
Change in unrealized gains/(losses) related to financial instruments held	$ 37	$ 16	$ 66	$ 21