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Investment Information - Net realized gains and losses (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Available for sale securities:
Available for sale securities, gross gains on investment sales		$ 17	$ 20
Available for sale securities, gross losses on investment sales		(111)	(108)
Equity securities, at fair value:
Net realized gains (losses) on sales during the period		19	65
Net unrealized gains (losses) on equity securities still held at reporting date		38	(176)
Allowance for credit losses:
Allowance for credit losses - investments related		(16)	(32)
Allowance for credit losses - underwriting related		0	(4)
Derivative instruments	[1]	56	(24)
Other		(2)	(3)
Net realized gains (losses)		17	(292)
Fixed maturities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		6	(31)
Other investments
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		9	4
Equity securities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		$ 1	$ (3)
[1] See note 9 for information on the Company’s derivative instruments.

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