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, 2021	Dec. 31, 2020	Dec. 31, 2019
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized gains (losses) on securities	$ 110	$ (75)	$ 155
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	86	(49)	129
Realized - impairments	1	(10)	(6)
Realized gains (losses) on securities	87	(59)	123
Change in unrealized	(88)	48	138
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	109	(62)	163
Realized - impairments	1	(13)	(8)
Realized gains (losses) on securities	110	(75)	155
Change in unrealized	(111)	61	174
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(1)	6	7
Realized - impairments	1	(13)	(8)
Realized gains (losses) on securities	0	(7)	(1)
Change in unrealized	(111)	61	174
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	110	(70)	155
Realized - impairments	0	0	0
Realized gains (losses) on securities	110	(70)	155
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	0	2	1
Realized - impairments	0	0	0
Realized gains (losses) on securities	0	2	1
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)	13	(34)
Realized - impairments	0	3	2
Realized gains (losses) on securities	(23)	16	(32)
Change in unrealized	$ 23	$ (13)	$ (36)