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Investments - Narrative (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($) security | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Investment [Line Items] |  |  |
Percentage (based on amount of unrealized loss) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade | 92.00% |  |
Percentage (based on fair value) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade | 96.00% |  |
Other than temporary impairment charges | $ 19 | $ 73 | $ 116
Average life of ABS | 4 years 6 months |  |
Average life of MBS | 4 years 6 months |  |
Residential MBS |  |  |
Investment [Line Items] |  |  |
Non-credit related portion of other-than-temporary impairment charges taken for securities still owned | $ 140 | 158 |
Fixed maturities, Gross Unrealized, Losses | (9) | (6) |
Other than temporary impairment charges | 6 | 1 | 3
Securities with non-credit other-than-temporary impairment charges |  |  |
Investment [Line Items] |  |  |
Gross Unrealized, Gains | 119 | 137 |
Gross Unrealized, Losses | (4) | (4) |
Fixed maturities |  |  |
Investment [Line Items] |  |  |
Fixed maturities, Gross Unrealized, Losses | $ (603) | (82) |
Number of available for sale securities in an unrealized loss position | security | 2,324 |  |
Other than temporary impairment charges | $ 26 | 20 | 38
Available-for-sale Securities, Gross Realized Gains | 22 | 43 | 55
Available-for-sale Securities, Gross Realized Losses | (14) | (20) | (10)
Fixed maturities excluding residential MBS |  |  |
Investment [Line Items] |  |  |
Other than temporary impairment charges | 20 | 19 | 35
Other investments |  |  |
Investment [Line Items] |  |  |
Other than temporary impairment charges |  | 4 |
Equity securities |  |  |
Investment [Line Items] |  |  |
Other than temporary impairment charges | 0 | 64 | 93
Available-for-sale Securities, Gross Realized Gains |  | 87 | 110
Available-for-sale Securities, Gross Realized Losses |  | (17) | (4)
Equity securities | Available-for-sale securities |  |  |
Investment [Line Items] |  |  |
Other than temporary impairment charges |  | $ 64 | $ 93
Aircraft financing | Fixed maturities excluding residential MBS |  |  |
Investment [Line Items] |  |  |
Other than temporary impairment charges | $ 14 |  |

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