Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 21,153	$ 6,383
Available for sale, gross unrealized losses less than 12 months	76	16
Available for sale, fair value 12 months or longer	18,648	22,572
Available for sale, gross unrealized losses 12 months or longer	369	520
Available for sale, fair value total	39,801	28,955
Available for sale, gross unrealized losses total	445	536
Direct obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	10,465	333
Available for sale, gross unrealized losses less than 12 months	15	2
Available for sale, fair value 12 months or longer	5,670	5,416
Available for sale, gross unrealized losses 12 months or longer	130	163
Available for sale, fair value total	16,135	5,749
Available for sale, gross unrealized losses total	145	165
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	2,021	961
Available for sale, gross unrealized losses less than 12 months	14	6
Available for sale, fair value 12 months or longer	5,469	6,512
Available for sale, gross unrealized losses 12 months or longer	116	158
Available for sale, fair value total	7,490	7,473
Available for sale, gross unrealized losses total	130	164
Total U.S. Treasury and federal agencies
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	12,486	1,294
Available for sale, gross unrealized losses less than 12 months	29	8
Available for sale, fair value 12 months or longer	11,139	11,928
Available for sale, gross unrealized losses 12 months or longer	246	321
Available for sale, fair value total	23,625	13,222
Available for sale, gross unrealized losses total	275	329
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	454	424
Available for sale, gross unrealized losses less than 12 months	0	1
Available for sale, fair value 12 months or longer	521	719
Available for sale, gross unrealized losses 12 months or longer	4	6
Available for sale, fair value total	975	1,143
Available for sale, gross unrealized losses total	4	7
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	178	358
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	851	1,052
Available for sale, gross unrealized losses 12 months or longer	3	13
Available for sale, fair value total	1,029	1,410
Available for sale, gross unrealized losses total	3	13
Non-U.S. sovereign, supranational and non-U.S. agency
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	7,451	3,972
Available for sale, gross unrealized losses less than 12 months	44	7
Available for sale, fair value 12 months or longer	5,089	5,788
Available for sale, gross unrealized losses 12 months or longer	86	125
Available for sale, fair value total	12,540	9,760
Available for sale, gross unrealized losses total	130	132
Other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	378	50
Available for sale, gross unrealized losses less than 12 months	1	0
Available for sale, fair value 12 months or longer	660	893
Available for sale, gross unrealized losses 12 months or longer	24	37
Available for sale, fair value total	1,038	943
Available for sale, gross unrealized losses total	25	37
Total non-U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	8,461	4,804
Available for sale, gross unrealized losses less than 12 months	45	8
Available for sale, fair value 12 months or longer	7,121	8,452
Available for sale, gross unrealized losses 12 months or longer	117	181
Available for sale, fair value total	15,582	13,256
Available for sale, gross unrealized losses total	162	189
Collateralized loan obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		183
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		1,605
Available for sale, gross unrealized losses 12 months or longer		6
Available for sale, fair value total		1,788
Available for sale, gross unrealized losses total		6
Non-agency CMBS and RMBS
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	25	35
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	99	180
Available for sale, gross unrealized losses 12 months or longer	1	3
Available for sale, fair value total	124	215
Available for sale, gross unrealized losses total	1	3
Total asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	25	218
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	99	1,785
Available for sale, gross unrealized losses 12 months or longer	1	9
Available for sale, fair value total	124	2,003
Available for sale, gross unrealized losses total	1	9
State and political subdivisions
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	181	64
Available for sale, gross unrealized losses less than 12 months	2	0
Available for sale, fair value 12 months or longer	156	104
Available for sale, gross unrealized losses 12 months or longer	1	1
Available for sale, fair value total	337	168
Available for sale, gross unrealized losses total	3	1
Other U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	0	3
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	133	303
Available for sale, gross unrealized losses 12 months or longer	4	8
Available for sale, fair value total	133	306
Available for sale, gross unrealized losses total	$ 4	$ 8

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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