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Fair Value Measurements - Changes in balances of Level 3 financial liabilities carried at fair value (Details) - USD ($) $ in Millions |  | 3 Months Ended | 6 Months Ended
--- | --- | --- | ---
May 31, 2021 | Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |  |
Financial liabilities, Beginning Balance |  | $ (3,954) | $ (3,099) | $ (3,933) | $ (3,730)
Total realized/unrealized gains (losses) included in Net income |  | (183) | (601) | (222) | 46
Total realized/unrealized gains (losses) included in other comprehensive income (loss) |  | 0 | 0 | 0 | 0
Purchases and issuances |  | (72) | (46) | (146) | (124)
Sales and settlements |  | 66 | 71 | 158 | 133
Transfer into Level 3 |  | 0 | 0 | 0 | 0
Transfer out of Level 3 |  | 0 | 0 | 0 | 0
Sale of annuity business | $ 4,143 |  |  |  |
Financial liabilities, Ending Balance |  | 0 | (3,675) | 0 | (3,675)
Liabilities of discontinued annuity operations | Annuity subsidiaries |  |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |  |
Financial liabilities, Beginning Balance |  | (3,954) | (3,099) | (3,933) | (3,730)
Total realized/unrealized gains (losses) included in Net income |  | (183) | (601) | (222) | 46
Total realized/unrealized gains (losses) included in other comprehensive income (loss) |  | 0 | 0 | 0 | 0
Purchases and issuances |  | (72) | (46) | (146) | (124)
Sales and settlements |  | 66 | 71 | 158 | 133
Transfer into Level 3 |  | 0 | 0 | 0 | 0
Transfer out of Level 3 |  | 0 | 0 | 0 | 0
Sale of annuity business | $ 4,143 |  |  |  |
Financial liabilities, Ending Balance |  | $ 0 | $ (3,675) | $ 0 | $ (3,675)

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- Definition Fair value measurement with unobservable inputs reconciliation, recurring basis, liability, disposition of subsidiaries + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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