Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 41,232	$ 7,490
Available for sale, gross unrealized losses less than 12 months	422	19
Available for sale, fair value 12 months or longer	2,277	1,351
Available for sale, gross unrealized losses 12 months or longer	23	7
Available for sale, fair value total	43,509	8,841
Available for sale, gross unrealized losses total	445	26
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	14,749	1,636
Available for sale, gross unrealized losses less than 12 months	194	1
Available for sale, fair value 12 months or longer	1,624	0
Available for sale, gross unrealized losses 12 months or longer	2	0
Available for sale, fair value total	16,373	1,636
Available for sale, gross unrealized losses total	196	1
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	10,417	1,394
Available for sale, gross unrealized losses less than 12 months	80	7
Available for sale, fair value 12 months or longer	369	63
Available for sale, gross unrealized losses 12 months or longer	14	0
Available for sale, fair value total	10,786	1,457
Available for sale, gross unrealized losses total	94	7
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	25,166	3,030
Available for sale, gross unrealized losses less than 12 months	274	8
Available for sale, fair value 12 months or longer	1,993	63
Available for sale, gross unrealized losses 12 months or longer	16	0
Available for sale, fair value total	27,159	3,093
Available for sale, gross unrealized losses total	290	8
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	577	600
Available for sale, gross unrealized losses less than 12 months	3	1
Available for sale, fair value 12 months or longer	30	120
Available for sale, gross unrealized losses 12 months or longer	0	1
Available for sale, fair value total	607	720
Available for sale, gross unrealized losses total	3	2
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	1,021	1,015
Available for sale, gross unrealized losses less than 12 months	2	3
Available for sale, fair value 12 months or longer	127	446
Available for sale, gross unrealized losses 12 months or longer	0	1
Available for sale, fair value total	1,148	1,461
Available for sale, gross unrealized losses total	2	4
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	10,406	489
Available for sale, gross unrealized losses less than 12 months	97	0
Available for sale, fair value 12 months or longer	63	0
Available for sale, gross unrealized losses 12 months or longer	3	0
Available for sale, fair value total	10,469	489
Available for sale, gross unrealized losses total	100	0
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	1,570	715
Available for sale, gross unrealized losses less than 12 months	31	3
Available for sale, fair value 12 months or longer	19	80
Available for sale, gross unrealized losses 12 months or longer	1	0
Available for sale, fair value total	1,589	795
Available for sale, gross unrealized losses total	32	3
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	13,574	2,819
Available for sale, gross unrealized losses less than 12 months	133	7
Available for sale, fair value 12 months or longer	239	646
Available for sale, gross unrealized losses 12 months or longer	4	2
Available for sale, fair value total	13,813	3,465
Available for sale, gross unrealized losses total	137	9
Asset-backed securities, student loans
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		31
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		197
Available for sale, gross unrealized losses 12 months or longer		1
Available for sale, fair value total		228
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	1,268	1,498
Available for sale, gross unrealized losses less than 12 months	2	4
Available for sale, fair value 12 months or longer	0	369
Available for sale, gross unrealized losses 12 months or longer	0	2
Available for sale, fair value total	1,268	1,867
Available for sale, gross unrealized losses total	2	6
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,268	1,529
Available for sale, gross unrealized losses less than 12 months	2	4
Available for sale, fair value 12 months or longer	0	566
Available for sale, gross unrealized losses 12 months or longer	0	3
Available for sale, fair value total	1,268	2,095
Available for sale, gross unrealized losses total	2	7
State and political subdivisions
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	10	95
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	45	76
Available for sale, gross unrealized losses 12 months or longer	3	2
Available for sale, fair value total	55	171
Available for sale, gross unrealized losses total	3	2
Other U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,214	17
Available for sale, gross unrealized losses less than 12 months	13	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	1,214	17
Available for sale, gross unrealized losses total	$ 13	$ 0

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

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