Investment Securities - Summary of Unrealized Losses on Available-for-Sale Securities (Details) $ in Millions	Mar. 31, 2022 USD ($) Investment	Dec. 31, 2021 USD ($) Investment
Debt Securities, Available-for-sale [Line Items]
Number of investments in unrealized loss position \| Investment	627	475
Number of investments with unrealized losses greater than 12 months \| Investment	132	4
Fair Value of Investments, Less than 12 months	$ 18,037	$ 17,596
Unrealized Losses, Less than 12 months	824	304
Fair Value of Investments, 12 months or longer	4,401	163
Unrealized Losses, 12 months or longer	479	9
Fair Value of Investments	22,438	17,759
Unrealized Losses	1,303	313
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Fair Value of Investments, Less than 12 months	13,377	7,777
Unrealized Losses, Less than 12 months	515	70
Fair Value of Investments, 12 months or longer	46	0
Unrealized Losses, 12 months or longer	4	0
Fair Value of Investments	13,423	7,777
Unrealized Losses	519	70
U.S. agency debentures
Debt Securities, Available-for-sale [Line Items]
Fair Value of Investments, Less than 12 months	76	196
Unrealized Losses, Less than 12 months	2	4
Fair Value of Investments, 12 months or longer	74	0
Unrealized Losses, 12 months or longer	9	0
Fair Value of Investments	150	196
Unrealized Losses	11	4
Residential mortgage-backed securities \| Agency-issued mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value of Investments, Less than 12 months	2,548	8,280
Unrealized Losses, Less than 12 months	193	210
Fair Value of Investments, 12 months or longer	4,027	0
Unrealized Losses, 12 months or longer	433	0
Fair Value of Investments	6,575	8,280
Unrealized Losses	626	210
Residential mortgage-backed securities \| Agency-issued collateralized mortgage obligations—fixed rate
Debt Securities, Available-for-sale [Line Items]
Fair Value of Investments, Less than 12 months	782	740
Unrealized Losses, Less than 12 months	44	9
Fair Value of Investments, 12 months or longer	71	0
Unrealized Losses, 12 months or longer	7	0
Fair Value of Investments	853	740
Unrealized Losses	51	9
Agency-issued commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value of Investments, Less than 12 months	1,254	603
Unrealized Losses, Less than 12 months	70	11
Fair Value of Investments, 12 months or longer	183	163
Unrealized Losses, 12 months or longer	26	9
Fair Value of Investments	1,437	766
Unrealized Losses	$ 96	$ 20

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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