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Income Taxes - Additional Information (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Additional Information [Line Items] |  |  |
Pre-tax earnings from foreign operations | $ 293 | $ 215 | $ 382
Other comprehensive income (loss), provision (benefit) | 702 | 447 | 15
Other comprehensive income (loss), provision (benefit) including HTM portfolio transfer |  | 727 |
Increase in valuation allowance | 73 |  |
Valuation allowance | 296 | 223 |
Accrued interest and penalties expense (benefit) related to income taxes included in income tax expense | 16 | 4 | $ 6
Unremitted earnings | 1,600 |  |
Amount of unrecognized deferred tax liability, bad debt reserve for tax purposes of qualified lender | 69 |  |
Bad debt reserve for tax purposes of qualified lender | 287 |  |
Foreign Tax Credit Carryforward |  |  |
Additional Information [Line Items] |  |  |
Increase in valuation allowance | 56 |  |
Internal Revenue Service (IRS) |  |  |
Additional Information [Line Items] |  |  |
Operating loss carryforwards | 36 | 31 |
Operating loss carryforwards, no expiration | 26 |  |
State and Local Jurisdiction |  |  |
Additional Information [Line Items] |  |  |
Operating loss carryforwards | 250 | 237 |
Foreign Tax Authority |  |  |
Additional Information [Line Items] |  |  |
Operating loss carryforwards | $ 56 | $ 40 |

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