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Investment Securities - Investment Available for Sale (Details) - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 92,973 | $ 94,871
Allowance for Credit Losses | (1) | (1)
Gross Unrealized Gains | 449 | 1,387
Gross Unrealized Losses | (4,345) | (996)
Securities available for sale | 89,076 | 95,261
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 9,521 | 9,419
Allowance for Credit Losses | 0 | 0
Gross Unrealized Gains | 5 | 23
Gross Unrealized Losses | (29) | 0
Securities available for sale | 9,497 | 9,442
RMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 71,292 | 72,593
Allowance for Credit Losses | 0 | 0
Gross Unrealized Gains | 231 | 958
Gross Unrealized Losses | (3,999) | (931)
Securities available for sale | 67,524 | 72,620
RMBS, Non-agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 728 | 792
Allowance for Credit Losses | (1) | (1)
Gross Unrealized Gains | 175 | 205
Gross Unrealized Losses | (1) | 0
Securities available for sale | 901 | 996
RMBS |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 72,020 | 73,385
Allowance for Credit Losses | (1) | (1)
Gross Unrealized Gains | 406 | 1,163
Gross Unrealized Losses | (4,000) | (931)
Securities available for sale | 68,425 | 73,616
CMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 8,634 | 9,237
Allowance for Credit Losses | 0 | 0
Gross Unrealized Gains | 35 | 195
Gross Unrealized Losses | (304) | (63)
Securities available for sale | 8,365 | 9,369
Other securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,798 | 2,830
Allowance for Credit Losses | 0 | 0
Gross Unrealized Gains | 3 | 6
Gross Unrealized Losses | (12) | (2)
Securities available for sale | 2,789 | 2,834
Asset-backed Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Securities available for sale | $ 2,000 | $ 2,000
US Treasury and Agency securities | Available-for-sale securities | Government Contracts Concentration Risk |  |
Debt Securities, Available-for-sale [Line Items] |  |
Percentage of portfolio | 96.00% | 96.00%

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