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		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized gains (losses) on securities		$ 204	$ 56	$ (347)	$ 240
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		160	46	(239)	193
Realized — impairments		1	(1)	(35)	(3)
Realized gains (losses) on securities		161	45	(274)	190
Change in unrealized		1,014	348	168	729
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		203	58	(302)	244
Realized — impairments		1	(2)	(45)	(4)
Realized gains (losses) on securities		204	56	(347)	240
Change in unrealized		1,284	440	213	923
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		3	11	32	14
Realized — impairments		1	(3)	(60)	(6)
Realized gains (losses) on securities		4	8	(28)	8
Change in unrealized		2,343	789	456	1,642
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		202	44	(333)	226
Realized — impairments		0	0	0	0
Realized gains (losses) on securities		202	44	(333)	226
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	3	4	3
Realized — impairments		0	0	0	0
Realized gains (losses) on securities		0	3	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)	0	(5)	1
Realized — impairments	[1]	0	1	15	2
Realized gains (losses) on securities	[1]	(2)	1	10	3
Change in unrealized	[1]	(1,059)	(349)	(243)	(719)
Tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(43)	(12)	63	(51)
Realized — impairments		0	1	10	1
Realized gains (losses) on securities		(43)	(11)	73	(50)
Change in unrealized		$ (270)	$ (92)	$ (45)	$ (194)

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