Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 15,997	$ 6,383
Available for sale, gross unrealized losses less than 12 months	40	16
Available for sale, fair value 12 months or longer	11,583	22,572
Available for sale, gross unrealized losses 12 months or longer	153	520
Available for sale, fair value total	27,580	28,955
Available for sale, gross unrealized losses total	193	536
Direct obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	11,115	333
Available for sale, gross unrealized losses less than 12 months	28	2
Available for sale, fair value 12 months or longer	2,436	5,416
Available for sale, gross unrealized losses 12 months or longer	32	163
Available for sale, fair value total	13,551	5,749
Available for sale, gross unrealized losses total	60	165
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	460	961
Available for sale, gross unrealized losses less than 12 months	2	6
Available for sale, fair value 12 months or longer	4,774	6,512
Available for sale, gross unrealized losses 12 months or longer	86	158
Available for sale, fair value total	5,234	7,473
Available for sale, gross unrealized losses total	88	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	11,575	1,294
Available for sale, gross unrealized losses less than 12 months	30	8
Available for sale, fair value 12 months or longer	7,210	11,928
Available for sale, gross unrealized losses 12 months or longer	118	321
Available for sale, fair value total	18,785	13,222
Available for sale, gross unrealized losses total	148	329
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	750	424
Available for sale, gross unrealized losses less than 12 months	1	1
Available for sale, fair value 12 months or longer	381	719
Available for sale, gross unrealized losses 12 months or longer	2	6
Available for sale, fair value total	1,131	1,143
Available for sale, gross unrealized losses total	3	7
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	221	358
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	667	1,052
Available for sale, gross unrealized losses 12 months or longer	2	13
Available for sale, fair value total	888	1,410
Available for sale, gross unrealized losses total	2	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	3,220	3,972
Available for sale, gross unrealized losses less than 12 months	9	7
Available for sale, fair value 12 months or longer	3,126	5,788
Available for sale, gross unrealized losses 12 months or longer	25	125
Available for sale, fair value total	6,346	9,760
Available for sale, gross unrealized losses total	34	132
Other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	231	50
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	146	893
Available for sale, gross unrealized losses 12 months or longer	4	37
Available for sale, fair value total	377	943
Available for sale, gross unrealized losses total	4	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	4,422	4,804
Available for sale, gross unrealized losses less than 12 months	10	8
Available for sale, fair value 12 months or longer	4,320	8,452
Available for sale, gross unrealized losses 12 months or longer	33	181
Available for sale, fair value total	8,742	13,256
Available for sale, gross unrealized losses total	43	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		35
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		180
Available for sale, gross unrealized losses 12 months or longer		3
Available for sale, fair value total		215
Available for sale, gross unrealized losses total		3
Total asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		218
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		1,785
Available for sale, gross unrealized losses 12 months or longer		9
Available for sale, fair value total		2,003
Available for sale, gross unrealized losses total		9
State and political subdivisions
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		64
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		104
Available for sale, gross unrealized losses 12 months or longer		1
Available for sale, fair value total		168
Available for sale, gross unrealized losses total		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	53	303
Available for sale, gross unrealized losses 12 months or longer	2	8
Available for sale, fair value total	53	306
Available for sale, gross unrealized losses total	$ 2	$ 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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