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Investments (Narrative) (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Debt securities, available-for-sale, accrued interest, after allowance for credit loss | $ 387,000,000 | $ 390,000,000 | $ 387,000,000 | $ 390,000,000 | $ 371,000,000
Mortgage loan losses due to changes in expected credit losses | 0 | 3,000,000 | 0 | 16,000,000 |
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments | 2,481,000,000 |  | 2,481,000,000 |  | 2,773,000,000
Notional value | 272,000,000 |  | 272,000,000 |  | 190,000,000
Derivative liability, fair value, gross liability | (11,000,000) |  | (11,000,000) |  | $ (19,000,000)
Commitments to purchase or fund privately placed debt securities | 1,250,000,000 |  | 1,250,000,000 |  |
Commitments to sell various privately placed debt securities | 55,000,000 |  | 55,000,000 |  |
5.750%, face amount of $400, due August 15, 2021 | Senior Notes |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Equity securities, FV-NI, gain (loss) |  | (20,000,000) |  | (20,000,000) |
Face amount | 400,000,000 |  | 400,000,000 |  |
Common Stock |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Equity securities, FV-NI, gain (loss) | (7,000,000) | 4,000,000 | 11,000,000 | 9,000,000 |
Non-redeemable preferred stock |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Equity securities, FV-NI, gain (loss) | (2,000,000) | $ 25,000,000 | 15,000,000 | $ (44,000,000) |
Mortgage loans |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Financing receivable, accrued interest, after allowance for credit loss | $ 4,000,000 |  | $ 4,000,000 |  |

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