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Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Gain (Loss) on Securities [Line Items] |  |  |  |
Realized Investment Gains (Losses) | $ (33) | $ 30 | $ 854 | $ (928)
Equity Securities [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Equity Securities, FV-NI, Realized Gain (Loss) | 150 | 148 | 517 | 119
Less: Net gains (losses) recognized from sales of securities | 45 | 187 | 90 | 163
Unrealized gains (losses) recognized for securities still held at reporting date | 105 | (39) | 427 | (44)
Other Investments [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Realized Investment Gains (Losses) | 62 | (107) | 100 | (102)
Less: Net gains (losses) recognized from sales of securities | 0 | 0 | 0 | 0
Unrealized gains (losses) recognized for securities still held at reporting date | 62 | (107) | 100 | (102)
Equity securities and other investments [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Realized Investment Gains (Losses) | 212 | 41 | 617 | 17
Less: Net gains (losses) recognized from sales of securities | 45 | 187 | 90 | 163
Unrealized gains (losses) recognized for securities still held at reporting date | $ 167 | $ (146) | $ 527 | $ (146)

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- Definition Amount of realized gain (loss) from sale of 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/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714 Reference 2: 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 http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
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- Definition The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Definition Amount of realized gain (loss) on investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.3(a)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
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- Definition Amount of unrealized gain (loss) on investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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