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
		Mar. 31, 2020	Mar. 31, 2019
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		$ (505)	$ 186
Realized gains (losses) on securities		(551)	184
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(399)	147
Realized — impairments		(36)	(2)
Realized gains (losses) on securities		(435)	145
Change in unrealized		(846)	381
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(505)	186
Realized — impairments		(46)	(2)
Realized gains (losses) on securities		(551)	184
Change in unrealized		(1,071)	483
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		29	3
Realized — impairments		(61)	(3)
Realized gains (losses) on securities		(32)	0
Change in unrealized		(1,887)	853
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(535)	182
Realized — impairments		0	0
Realized gains (losses) on securities		(535)	182
Change in unrealized		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		4	0
Realized — impairments		0	0
Realized gains (losses) on securities		4	0
Change in unrealized		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]	(3)	1
Realized — impairments	[1]	15	1
Realized gains (losses) on securities	[1]	12	2
Change in unrealized	[1]	816	(370)
Tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		106	(39)
Realized — impairments		10	0
Realized gains (losses) on securities		116	(39)
Change in unrealized		$ 225	$ (102)

[1] Primarily adjustments to deferred policy acquisition costs and reserves related to the annuity business.