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Investments - Holding gains (losses) on equity securities still held (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
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Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Holding Gains (Losses) on Equity Securities Still Held [Line Items] |  |  |  |
Holding gains (losses) on equity securities still held | $ (91) | $ 44 | $ (100) | $ 132
Realized gains (losses) on securities |  |  |  |
Holding Gains (Losses) on Equity Securities Still Held [Line Items] |  |  |  |
Holding gains (losses) on equity securities still held | (82) | 36 | (96) | 98
Investment income |  |  |  |
Holding Gains (Losses) on Equity Securities Still Held [Line Items] |  |  |  |
Holding gains (losses) on equity securities still held | $ (9) | $ 8 | $ (4) | $ 34

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- Definition holding gains (losses) on equity securities still held + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI https://asc.fasb.org/extlink&oid=126980263&loc=SL75117546-209714 + Details
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