Investments - Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized gains (losses) on securities	$ 45	$ (18)	$ (302)	$ 222
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	34	(7)	(205)	186
Realized — impairments	1	(7)	(34)	(10)
Realized gains (losses) on securities	35	(14)	(239)	176
Change in unrealized	182	108	350	837
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	43	(9)	(259)	235
Realized — impairments	2	(9)	(43)	(13)
Realized gains (losses) on securities	45	(18)	(302)	222
Change in unrealized	230	137	443	1,060
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	14	9	46	23
Realized — impairments	3	(14)	(57)	(20)
Realized gains (losses) on securities	17	(5)	(11)	3
Change in unrealized	513	367	969	2,009
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	30	(16)	(303)	210
Realized — impairments	0	0	0	0
Realized gains (losses) on securities	30	(16)	(303)	210
Change in unrealized	0	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	0	4	3
Realized — impairments	0	0	0	0
Realized gains (losses) on securities	0	0	4	3
Change in unrealized	0	0	0	0
Other, Including DPAC and reserves related to the annuity business
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(1)	(2)	(6)	(1)
Realized — impairments	(1)	5	14	7
Realized gains (losses) on securities	(2)	3	8	6
Change in unrealized	(283)	(230)	(526)	(949)
Tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(9)	2	54	(49)
Realized — impairments	(1)	2	9	3
Realized gains (losses) on securities	(10)	4	63	(46)
Change in unrealized	$ (48)	$ (29)	$ (93)	$ (223)