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Fair Value Measurement - Level 3 Recurring Fair Value Rollfoward (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Jan. 01, 2020
Derivative, Fair Value, Net [Abstract] |  |  |  |
Fair value of RMBS, cumulative effects from the CECL adoption |  |  |  | $ 4
Derivative assets, gross amount | $ 3,415 | $ 1,729 |  |
Derivative liabilities, gross amount | 1,518 | 1,197 |  |
Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Net Unrealized Gains (Losses) Included in OCI Related to Assets and Liabilities Still Held | (21) | (4) | $ (17) |
Derivative, Fair Value, Net [Abstract] |  |  |  |
Beginning balance | 26 | (10) | 13 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income | 10 | 6 | (20) |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI | 0 | 0 | 0 |
Purchases | 0 | 0 | 0 |
Sales | 0 | 0 | 0 |
Issuances | 43 | (16) | 13 |
Settlements | (37) | 52 | (17) |
Transfers Into Level 3 | 0 | 0 | 0 |
Transfers Out of Level 3 | (11) | (6) | 1 |
Ending balance | 31 | 26 | (10) |
Derivative assets, gross amount | 141 | 77 | 38 |
Derivative liabilities, gross amount | 110 | 51 | 48 |
RMBS | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 429 | 433 | 614 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income | 22 | 35 | 32 |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI | (19) | 5 | (8) |
Purchases | 0 | 0 | 0 |
Sales | 0 | 0 | 0 |
Issuances | 0 | 0 | 0 |
Settlements | (72) | (63) | (74) |
Transfers Into Level 3 | 206 | 177 | 203 |
Transfers Out of Level 3 | (242) | (158) | (334) |
Ending balance | 328 | 429 | 433 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held | 16 | 34 | 28 |
RMBS | Recurring | Level 3 | Including CECL Impact Adoption |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 433 |  |  |
Ending balance |  | 433 |  |
CMBS | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 13 | 10 | 14 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income | (3) | 0 | 0 |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI | (9) | 0 | 0 |
Purchases | 0 | 0 | 0 |
Sales | 0 | 0 | 0 |
Issuances | 0 | 0 | 0 |
Settlements | (32) | (2) | (4) |
Transfers Into Level 3 | 371 | 5 | 0 |
Transfers Out of Level 3 | (229) | 0 | 0 |
Ending balance | 111 | 13 | 10 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held | 0 | 0 | 0 |
Other securities | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance |  | 0 | 5 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income |  |  | 0 |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI |  |  | 0 |
Purchases |  |  | 0 |
Sales |  |  | 0 |
Issuances |  |  | 0 |
Settlements |  |  | (5) |
Transfers Into Level 3 |  |  | 0 |
Transfers Out of Level 3 |  |  | 0 |
Ending balance |  |  | 0 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held |  |  | 0 |
Available-for-sale securities | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 442 | 443 | 633 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income | 19 | 35 | 32 |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI | (28) | 5 | (8) |
Purchases | 0 | 0 | 0 |
Sales | 0 | 0 | 0 |
Issuances | 0 | 0 | 0 |
Settlements | (104) | (65) | (83) |
Transfers Into Level 3 | 577 | 182 | 203 |
Transfers Out of Level 3 | (471) | (158) | (334) |
Ending balance | 439 | 442 | 443 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held | 16 | 34 | 28 |
Available-for-sale securities | Recurring | Level 3 | Including CECL Impact Adoption |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 446 |  |  |
Ending balance |  | 446 |  |
Consumer MSRs | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance |  | 0 | 92 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income |  |  | 3 |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI |  |  | 0 |
Purchases |  |  | 0 |
Sales |  |  | (97) |
Issuances |  |  | 2 |
Settlements |  |  | 0 |
Transfers Into Level 3 |  |  | 0 |
Transfers Out of Level 3 |  |  | 0 |
Ending balance |  |  | 0 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held |  |  | 0 |
Retained interest in securitizations | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Beginning balance | 66 | 158 | 172 |
Total Gains or (Losses) (Realized/Unrealized), Included in Net Income | (11) | 18 | (14) |
Total Gains or (Losses) (Realized/Unrealized), Included in OCI | 0 | 0 | 0 |
Purchases | 0 | 0 | 0 |
Sales | 0 | 0 | 0 |
Issuances | 0 | 0 | 0 |
Settlements | 0 | (110) | 0 |
Transfers Into Level 3 | 0 | 0 | 0 |
Transfers Out of Level 3 | 0 | 0 | 0 |
Ending balance | 55 | 66 | 158 |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held | (11) | (19) | (14) |
Net derivative assets (liabilities) | Recurring | Level 3 |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held | $ 10 | $ 1 | $ (20) |

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