Investments - Realized Investment Gains and Losses and Change in Unrealized Investment Gains and Losses and Other Items (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Investment income:
Interest	$ 187	$ 154	$ 529	$ 441
Dividends	68	69	209	205
Other	7	5	18	18
Total	262	228	756	664
Less investment expenses	4	3	11	9
Total	258	225	745	655
Investment gains and losses, net
Other	3	6	29	(11)
Total	758	(456)	1,507	84
Equity securities
Investment gains and losses, net
Investment gains and losses on securities sold, net	24	(5)	146	2
Unrealized gains and losses on securities still held, net	817	(458)	1,446	99
Total	841	(463)	1,592	101
Fixed maturities
Investment gains and losses, net
Gross realized gains	1	1	5	2
Gross realized losses	(87)	(1)	(94)	(2)
Change in allowance for credit losses, net	0	1	(25)	(2)
Write-down of impaired securities with intent to sell	0	0	0	(4)
Total	$ (86)	$ 1	$ (114)	$ (6)

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