Investments - Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized gains (losses) on securities	$ (116)	$ 110	$ (75)
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(90)	86	(49)
Realized - impairments	(2)	1	(10)
Realized gains (losses) on securities	(92)	87	(59)
Change in unrealized	(633)	(88)	48
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(113)	109	(62)
Realized - impairments	(3)	1	(13)
Realized gains (losses) on securities	(116)	110	(75)
Change in unrealized	(803)	(111)	61
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(27)	(1)	6
Realized - impairments	(3)	1	(13)
Realized gains (losses) on securities	(30)	0	(7)
Change in unrealized	(803)	(111)	61
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(96)	110	(70)
Realized - impairments	0	0	0
Realized gains (losses) on securities	(96)	110	(70)
Change in unrealized	0	0	0
Mortgage loans and other investments
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	10	0	2
Realized - impairments	0	0	0
Realized gains (losses) on securities	10	0	2
Change in unrealized	0	0	0
Total tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	23	(23)	13
Realized - impairments	1	0	3
Realized gains (losses) on securities	24	(23)	16
Change in unrealized	$ 170	$ 23	$ (13)