Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 49,678	$ 41,232
Available for sale, gross unrealized losses less than 12 months	1,432	422
Available for sale, fair value 12 months or longer	7,218	2,277
Available for sale, gross unrealized losses 12 months or longer	411	23
Available for sale, fair value total	56,896	43,509
Available for sale, gross unrealized losses total	1,843	445
US Treasury and federal agencies, direct obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	16,587	14,749
Available for sale, gross unrealized losses less than 12 months	644	194
Available for sale, fair value 12 months or longer	3,454	1,624
Available for sale, gross unrealized losses 12 months or longer	114	2
Available for sale, fair value total	20,041	16,373
Available for sale, gross unrealized losses total	758	196
US Treasury and federal agencies, mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	11,858	10,417
Available for sale, gross unrealized losses less than 12 months	391	80
Available for sale, fair value 12 months or longer	880	369
Available for sale, gross unrealized losses 12 months or longer	89	14
Available for sale, fair value total	12,738	10,786
Available for sale, gross unrealized losses total	480	94
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	28,445	25,166
Available for sale, gross unrealized losses less than 12 months	1,035	274
Available for sale, fair value 12 months or longer	4,334	1,993
Available for sale, gross unrealized losses 12 months or longer	203	16
Available for sale, fair value total	32,779	27,159
Available for sale, gross unrealized losses total	1,238	290
Non-U.S. debt securities, mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,376	577
Available for sale, gross unrealized losses less than 12 months	10	3
Available for sale, fair value 12 months or longer	37	30
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	1,413	607
Available for sale, gross unrealized losses total	10	3
Non-U.S. debt securities, asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,650	1,021
Available for sale, gross unrealized losses less than 12 months	8	2
Available for sale, fair value 12 months or longer	76	127
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	1,726	1,148
Available for sale, gross unrealized losses total	8	2
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	12,826	10,406
Available for sale, gross unrealized losses less than 12 months	275	97
Available for sale, fair value 12 months or longer	1,744	63
Available for sale, gross unrealized losses 12 months or longer	134	3
Available for sale, fair value total	14,570	10,469
Available for sale, gross unrealized losses total	409	100
Non-U.S. debt securities, other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,675	1,570
Available for sale, gross unrealized losses less than 12 months	57	31
Available for sale, fair value 12 months or longer	665	19
Available for sale, gross unrealized losses 12 months or longer	53	1
Available for sale, fair value total	2,340	1,589
Available for sale, gross unrealized losses total	110	32
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	17,527	13,574
Available for sale, gross unrealized losses less than 12 months	350	133
Available for sale, fair value 12 months or longer	2,522	239
Available for sale, gross unrealized losses 12 months or longer	187	4
Available for sale, fair value total	20,049	13,813
Available for sale, gross unrealized losses total	537	137
Asset-backed securities, student loans
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	93
Available for sale, gross unrealized losses less than 12 months	1
Available for sale, fair value 12 months or longer	25
Available for sale, gross unrealized losses 12 months or longer	0
Available for sale, fair value total	118
Available for sale, gross unrealized losses total	1
Asset-backed securities, collateralized loan obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	2,021	1,268
Available for sale, gross unrealized losses less than 12 months	9	2
Available for sale, fair value 12 months or longer	49	0
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	2,070	1,268
Available for sale, gross unrealized losses total	9	2
Non-agency CMBS and RMBS
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	124
Available for sale, gross unrealized losses less than 12 months	2
Available for sale, fair value 12 months or longer	0
Available for sale, gross unrealized losses 12 months or longer	0
Available for sale, fair value total	124
Available for sale, gross unrealized losses total	2
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	2,238	1,268
Available for sale, gross unrealized losses less than 12 months	12	2
Available for sale, fair value 12 months or longer	74	0
Available for sale, gross unrealized losses 12 months or longer	0	0
Available for sale, fair value total	2,312	1,268
Available for sale, gross unrealized losses total	12	2
State and political subdivisions
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	361	10
Available for sale, gross unrealized losses less than 12 months	3	0
Available for sale, fair value 12 months or longer	44	45
Available for sale, gross unrealized losses 12 months or longer	4	3
Available for sale, fair value total	405	55
Available for sale, gross unrealized losses total	7	3
Other U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,107	1,214
Available for sale, gross unrealized losses less than 12 months	32	13
Available for sale, fair value 12 months or longer	244	0
Available for sale, gross unrealized losses 12 months or longer	17	0
Available for sale, fair value total	1,351	1,214
Available for sale, gross unrealized losses total	$ 49	$ 13

Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]

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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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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 less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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