Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 26,332	$ 8,133
Available for sale, gross unrealized losses less than 12 months	133	35
Available for sale, fair value 12 months or longer	5,995	8,265
Available for sale, gross unrealized losses 12 months or longer	65	62
Available for sale, fair value total	32,327	16,398
Available for sale, gross unrealized losses total	198	97
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	11,086	2,023
Available for sale, gross unrealized losses less than 12 months	27	5
Available for sale, fair value 12 months or longer	4,801	6,081
Available for sale, gross unrealized losses 12 months or longer	58	54
Available for sale, fair value total	15,887	8,104
Available for sale, gross unrealized losses total	85	59
Direct obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	7,663	756
Available for sale, gross unrealized losses less than 12 months	7	2
Available for sale, fair value 12 months or longer	1,461	2,063
Available for sale, gross unrealized losses 12 months or longer	3	3
Available for sale, fair value total	9,124	2,819
Available for sale, gross unrealized losses total	10	5
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	3,423	1,267
Available for sale, gross unrealized losses less than 12 months	20	3
Available for sale, fair value 12 months or longer	3,340	4,018
Available for sale, gross unrealized losses 12 months or longer	55	51
Available for sale, fair value total	6,763	5,285
Available for sale, gross unrealized losses total	75	54
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	13,133	5,042
Available for sale, gross unrealized losses less than 12 months	102	29
Available for sale, fair value 12 months or longer	1,089	2,184
Available for sale, gross unrealized losses 12 months or longer	7	8
Available for sale, fair value total	14,222	7,226
Available for sale, gross unrealized losses total	109	37
Mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,295	617
Available for sale, gross unrealized losses less than 12 months	3	1
Available for sale, fair value 12 months or longer	50	73
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	1,345	690
Available for sale, gross unrealized losses total	3	1
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	943	425
Available for sale, gross unrealized losses less than 12 months	1	0
Available for sale, fair value 12 months or longer	163	168
Available for sale, gross unrealized losses 12 months or longer	0	1
Available for sale, fair value total	1,106	593
Available for sale, gross unrealized losses total	1	1
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	10,381	3,871
Available for sale, gross unrealized losses less than 12 months	94	28
Available for sale, fair value 12 months or longer	876	1,943
Available for sale, gross unrealized losses 12 months or longer	7	7
Available for sale, fair value total	11,257	5,814
Available for sale, gross unrealized losses total	101	35
Other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	514	129
Available for sale, gross unrealized losses less than 12 months	4	0
Available for sale, fair value 12 months or longer	0	0
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	514	129
Available for sale, gross unrealized losses total	4	0
Total asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	2,113	1,068
Available for sale, gross unrealized losses less than 12 months	4	1
Available for sale, fair value 12 months or longer	105	0
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	2,218	1,068
Available for sale, gross unrealized losses total	4	1
Collateralized loan obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	2,113	1,068
Available for sale, gross unrealized losses less than 12 months	4	1
Available for sale, fair value 12 months or longer	105	0
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	2,218	1,068
Available for sale, gross unrealized losses total	$ 4	$ 1

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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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