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Future Policy Benefit Reserves - Narrative (Details) - USD ($) | 3 Months Ended | 6 Months Ended
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Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Insurance [Abstract] |  |  |  |
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact | $ (33,000,000) | $ 1,000,000 | $ (34,000,000) | $ 6,000,000
Liability for future policy benefit, expected future gross premium, discounted, before reinsurance | $ 3,853,000,000 | $ 4,204,000,000 | $ 3,853,000,000 | $ 4,204,000,000
Liability for future policy benefit, weighted-average duration | 12 years | 12 years | 12 years | 12 years
Liability for future policy benefit, adverse development, expense | $ 29,000,000 | $ 1,000,000 | $ 42,000,000 | $ 1,000,000
Liability future policy benefit, losses recognized in prior period | $ 1,000,000 | $ 0 | $ 11,000,000 | $ 1,000,000

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- Definition Insurance Claims And Policyholders Benefits, Including Policyholders' Dividends, Remeasurement Impact + References No definition available. + Details
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- Definition Liability For Future Policy Benefit, Losses Recognized In Prior Period Reversed Due To Favorable Development + References No definition available. + Details
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- Definition Amount of expense for adverse development on liability of future policy benefit from net premium exceeding gross premium. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Subparagraph (g)(2)(iii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480016/944-40-65-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-6 + Details
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- Definition Amount, before effect of reinsurance, of discounted balance for expected future gross premium component of liability for future policy benefit. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-6 + Details
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- Definition Weighted-average duration of liability for future policy benefit, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(5) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-6 + Details
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