Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	$ (101)	$ (77)
Equity Securities
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	3	11
Less: Net gains (losses) recognized from sales of securities	(3)	(5)
Unrealized Gain (Loss) on Investments	6	16
Other Investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	168	0
Less: Net gains (losses) recognized from sales of securities	0
Unrealized Gain (Loss) on Investments	168
Alternative Investment
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	31	15
Less: Net gains (losses) recognized from sales of securities	0	0
Unrealized Gain (Loss) on Investments	31	15
Equity securities and other investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	202	26
Less: Net gains (losses) recognized from sales of securities	(3)	(5)
Unrealized Gain (Loss) on Investments	$ 205	$ 31

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).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(d)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
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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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Subparagraph (b)
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-Topic 230
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(9)(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-9

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