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Investments - OTTI losses included in AOCI at the time of impairment for fixed income securities (Details) - USD ($) $ in Millions | Mar. 31, 2018 | Dec. 31, 2017
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Investments [Abstract] |  |
Net unrealized gains related to changes in valuation of fixed income securities subsequent to impairment measurement date | $ 202 | $ 208
Other-than Impairment Losses Included in Accumulated Other Comprehensive Income |  |
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings | (95) | (101)
Municipal |  |
Other-than Impairment Losses Included in Accumulated Other Comprehensive Income |  |
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings | (5) | (5)
Asset-backed securities (“ABS”) |  |
Other-than Impairment Losses Included in Accumulated Other Comprehensive Income |  |
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings | (12) | (15)
Residential mortgage-backed securities (“RMBS”) |  |
Other-than Impairment Losses Included in Accumulated Other Comprehensive Income |  |
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings | (74) | (77)
Commercial mortgage-backed securities (“CMBS”) |  |
Other-than Impairment Losses Included in Accumulated Other Comprehensive Income |  |
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings | $ (4) | $ (4)

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- Definition The pre-tax amount of other than temporary impairment loss on debt securities related to factors other than credit losses when the entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis. Such amount is included in accumulated other comprehensive income, attributable to the parent entity. + References No definition available. + Details
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