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Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions | Mar. 31, 2021 | Dec. 31, 2020 | Mar. 31, 2020 | Jan. 01, 2020 | Dec. 31, 2019
--- | --- | --- | --- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | $ 9,059 | $ 8,812 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 10 | 12 | $ 14 |  | $ 0
Available for sale (AFS) fixed maturities | 9,289 | 9,084 |  |  |
Total fixed maturities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 9,059 | 8,812 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 10 | 12 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 256 | 305 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (16) | (21) |  |  |
Available for sale (AFS) fixed maturities | 9,289 | 9,084 |  |  |
Total fixed maturities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 32,853 | 31,596 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 18 | 28 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 2,023 | 2,652 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (104) | (97) |  |  |
Available for sale (AFS) fixed maturities | 34,754 | 34,123 |  |  |
Total fixed maturities | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 240 | 284 |  |  |
Total fixed maturities | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 1,919 | 2,555 |  |  |
U.S. Government and government agencies |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 212 | 192 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 4 | 6 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (1) | 0 |  |  |
Available for sale (AFS) fixed maturities | 215 | 198 |  |  |
U.S. Government and government agencies | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 38 | 39 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 4 | 5 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | 0 |  |  |
Available for sale (AFS) fixed maturities | 42 | 44 |  |  |
U.S. Government and government agencies | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 3 | 6 |  |  |
U.S. Government and government agencies | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 4 | 5 |  |  |
States, municipalities and political subdivisions |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 2,076 | 2,196 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 91 | 116 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | 0 |  |  |
Available for sale (AFS) fixed maturities | 2,167 | 2,312 |  |  |
States, municipalities and political subdivisions | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 2,951 | 3,053 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 269 | 370 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (4) | (2) |  |  |
Available for sale (AFS) fixed maturities | 3,216 | 3,421 |  |  |
States, municipalities and political subdivisions | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 91 | 116 |  |  |
States, municipalities and political subdivisions | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 265 | 368 |  |  |
Foreign government |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 188 | 172 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 2 | 4 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | 0 |  |  |
Available for sale (AFS) fixed maturities | 190 | 176 |  |  |
Foreign government | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 31 | 31 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 3 | 4 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | 0 |  |  |
Available for sale (AFS) fixed maturities | 34 | 35 |  |  |
Foreign government | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 2 | 4 |  |  |
Foreign government | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 3 | 4 |  |  |
Residential MBS |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 796 | 859 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 53 | 57 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (2) | (1) |  |  |
Available for sale (AFS) fixed maturities | 847 | 915 |  |  |
Residential MBS | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 2,342 | 1,953 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 3 | 3 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 180 | 194 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (6) | (4) |  |  |
Available for sale (AFS) fixed maturities | 2,513 | 2,140 |  |  |
Residential MBS | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 51 | 56 |  |  |
Residential MBS | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 174 | 190 |  |  |
Commercial MBS |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 106 | 89 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 3 | 3 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | 0 |  |  |
Available for sale (AFS) fixed maturities | 109 | 92 |  |  |
Commercial MBS | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 603 | 659 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 0 | 0 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 33 | 40 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | 0 | (1) |  |  |
Available for sale (AFS) fixed maturities | 636 | 698 |  |  |
Commercial MBS | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 3 | 3 |  |  |
Commercial MBS | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 33 | 39 |  |  |
Collateralized loan obligations |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 1,131 | 1,065 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 1 | 3 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 4 | 4 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (3) | (4) |  |  |
Collateralized loan obligations | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 3,778 | 3,491 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 4 | 10 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 23 | 23 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (9) | (13) |  |  |
Collateralized loan obligations | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 1 | 0 |  |  |
Collateralized loan obligations | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 14 | 10 |  |  |
Other asset-backed securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 2,178 | 2,040 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 8 | 7 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 24 | 27 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (6) | (13) |  |  |
Available for sale (AFS) fixed maturities | 2,188 | 2,047 |  |  |
Other asset-backed securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 5,095 | 5,098 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 10 | 11 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 144 | 142 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (25) | (53) |  |  |
Available for sale (AFS) fixed maturities | 5,204 | 5,176 |  |  |
Other asset-backed securities | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 18 | 14 |  |  |
Other asset-backed securities | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 119 | 89 |  |  |
Corporate and other |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 2,372 | 2,199 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 1 | 2 | $ 3 | $ 0 | $ 0
Fixed maturities, Available for sale, Gross Unrealized, Gains | 75 | 88 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (4) | (3) |  |  |
Available for sale (AFS) fixed maturities | 2,442 | 2,282 |  |  |
Corporate and other | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available for sale, amortized cost | 18,015 | 17,272 |  |  |
Fixed maturities, available for sale, allowance for expected credit losses | 1 | 4 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Gains | 1,367 | 1,874 |  |  |
Fixed maturities, Available for sale, Gross Unrealized, Losses | (60) | (24) |  |  |
Available for sale (AFS) fixed maturities | 19,321 | 19,118 |  |  |
Corporate and other | Debt Securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 71 | 85 |  |  |
Corporate and other | Debt Securities | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax | 1,307 | 1,850 |  |  |
Managed by third parties | Collateralized loan obligations |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Available for sale (AFS) fixed maturities | 1,131 | 1,062 |  |  |
Managed by third parties | Collateralized loan obligations | Assets of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Available for sale (AFS) fixed maturities | $ 3,788 | $ 3,491 |  |  |

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