Investments (Schedule of Gains and Losses on Equity and Other Investments) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	$ (607)	$ (1,085)	$ 1,030
Unrealized gains (losses) recognized for securities still held at reporting date	3,120	(9,535)	(2,417)
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	(38)	(230)	662
Less: Net gains (losses) recognized from sales of securities	(68)	409	157
Unrealized gains (losses) recognized for securities still held at reporting date	30	(639)	505
Other Investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	(12)	0	0
Less: Net gains (losses) recognized from sales of securities	0
Unrealized gains (losses) recognized for securities still held at reporting date	(12)
Equity securities and other investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	20	(261)	773
Less: Net gains (losses) recognized from sales of securities	(68)	409	157
Unrealized gains (losses) recognized for securities still held at reporting date	88	(670)	616
Private equities
Gain (Loss) on Securities [Line Items]
Net realized gains (losses)	70	(31)	111
Less: Net gains (losses) recognized from sales of securities	0	0	0
Unrealized gains (losses) recognized for securities still held at reporting date	$ 70	$ (31)	$ 111

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
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Section S99
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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