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Investment Information - Net realized gains and losses (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Available for sale securities:
Available for sale securities, gross gains on investment sales		$ 50	$ 17
Available for sale securities, gross losses on investment sales		(78)	(111)
Equity securities, at fair value:
Net realized gains (losses) on sales during the period		11	19
Net unrealized gains (losses) on equity securities still held at reporting date		82	38
Allowance for credit losses:
Allowance for credit losses - investments related		(6)	(16)
Allowance for credit losses - underwriting related		1	0
Derivative instruments	[1]	(10)	56
Other		17	(2)
Net realized gains (losses)		67	17
Fixed maturities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		2	6
Other investments
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		(2)	9
Equity securities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		$ 0	$ 1
[1] See note 9 for information on the Company’s derivative instruments.

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- Definition

Includes realized gains and losses on debt securities accounted for as available for sale, realized and unrealized changes in the fair value of equity securities and assets and liabilities accounted for using the fair value option, realized and unrealized gains and losses on derivative instruments and changes in the allowance for credit losses on financial assets, and all other.

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