Investments - Realized Investment Gains and Losses and Change in Unrealized Investment Gains and Losses and Other Items (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Investment income:
Interest	$ 147	$ 124	$ 287	$ 247
Dividends	70	72	136	137
Other	6	2	13	3
Total	223	198	436	387
Less investment expenses	3	3	6	7
Total	220	195	430	380
Investment gains and losses, net
Other	(21)	16	(20)	22
Total	434	(1,154)	540	(1,820)
Equity securities
Investment gains and losses, net
Investment gains and losses on securities sold, net	0	5	(4)	37
Unrealized gains and losses on securities still held, net	459	(1,175)	568	(1,882)
Total	459	(1,170)	564	(1,845)
Fixed maturities
Investment gains and losses, net
Gross realized gains	0	2	1	6
Gross realized losses	0	(2)	(1)	(3)
Writedown of Impaired Securities Intended to be Sold	(4)	0	(4)	0
Total	$ (4)	$ 0	$ (4)	$ 3