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Investments - Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized gains (losses) on securities | $ 110 | $ (75) | $ 155
Net of tax |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | 86 | (49) | 129
Realized - impairments | 1 | (10) | (6)
Realized gains (losses) on securities | 87 | (59) | 123
Change in unrealized | (88) | 48 | 138
Total pretax |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | 109 | (62) | 163
Realized - impairments | 1 | (13) | (8)
Realized gains (losses) on securities | 110 | (75) | 155
Change in unrealized | (111) | 61 | 174
Fixed maturities |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | (1) | 6 | 7
Realized - impairments | 1 | (13) | (8)
Realized gains (losses) on securities | 0 | (7) | (1)
Change in unrealized | (111) | 61 | 174
Equity securities |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | 110 | (70) | 155
Realized - impairments | 0 | 0 | 0
Realized gains (losses) on securities | 110 | (70) | 155
Change in unrealized | 0 | 0 | 0
Mortgage loans and other investments |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | 0 | 2 | 1
Realized - impairments | 0 | 0 | 0
Realized gains (losses) on securities | 0 | 2 | 1
Change in unrealized | 0 | 0 | 0
Total tax effects |  |  |
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments |  |  |
Realized before impairments | (23) | 13 | (34)
Realized - impairments | 0 | 3 | 2
Realized gains (losses) on securities | (23) | 16 | (32)
Change in unrealized | $ 23 | $ (13) | $ (36)

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- Definition Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments. + References No definition available. + Details
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- Definition Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 8A -URI http://asc.fasb.org/extlink&oid=124260329&loc=SL6284422-111562 + Details
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