Deferred Policy Acquisition Costs - Progression of deferred policy acquisition costs (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Deferred policy acquisition costs and present value of future profits, beginning balance		$ 1,447	$ 1,417	$ 1,682	$ 1,216
Deferred policy acquisition costs and present value of future profits, additions		250	252	502	471
Deferred policy acquisition costs and present value of future profits, periodic amortization		(200)	(233)	(395)	(463)
Deferred policy acquisition costs and present value of future profits, annuity unlocking			29		29
Deferred policy acquisition costs and present value of future profits, change included in realized gains		1	3	3	6
Deferred policy acquisition costs and present value of future profits, foreign currency translation		(1)	(2)	0	(1)
Deferred policy acquisition costs and present value of future profits, change in unrealized		(294)	116	(589)	324
Deferred policy acquisition costs and present value of future profits, ending balance		1,203	1,582	1,203	1,582
P&C
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		312	279	299	270
Deferred policy acquisition costs, additions		194	181	381	343
Deferred policy acquisition costs, periodic amortization		(175)	(160)	(350)	(314)
Deferred policy acquisition costs, foreign currency translation		(1)	(2)	0	(1)
Deferred policy acquisition costs, ending balance		330	298	330	298
Annuity and Other
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		1,336	1,208	1,285	1,217
Deferred policy acquisition costs, additions		56	70	120	127
Deferred policy acquisition costs, periodic amortization		(19)	(66)	(34)	(135)
Deferred policy acquisition costs, annuity unlocking			28		28
Deferred policy acquisition costs, change included in realized gains		0	3	2	6
Deferred policy acquisition costs, ending balance		1,373	1,243	1,373	1,243
Movement in Deferred Sales Inducements [Roll Forward]
Deferred sales inducements, beginning balance		84	97	86	102
Deferred sales inducements, additions		0	1	1	1
Deferred sales inducements, periodic amortization		(4)	(5)	(7)	(10)
Deferred sales inducements, annuity unlocking			1		1
Deferred sales inducements, change included in realized gains		1	0	1	0
Deferred sales inducements, ending balance		81	94	81	94
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present value of future profits, beginning balance		40	47	42	49
Present value of future profits, periodic amortization		(2)	(2)	(4)	(4)
Present value of future profits, annuity unlocking			0		0
Present value of future profits, ending balance		38	45	38	45
Movement in Unrealized Gains (Losses) Related to Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Unrealized investment gains (losses), beginning balance	[1]	(325)	(214)	(30)	(422)
Unrealized investment gains (losses), change in unrealized	[1]	(294)	116	(589)	324
Unrealized investment gains (losses), ending balance	[1]	(619)	(98)	(619)	(98)
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Deferred policy acquisition costs and present value of future profits, beginning balance		1,135	1,138	1,383	946
Deferred policy acquisition costs and present value of future profits, additions		56	71	121	128
Deferred policy acquisition costs and present value of future profits, periodic amortization		(25)	(73)	(45)	(149)
Deferred policy acquisition costs and present value of future profits, annuity unlocking			29		29
Deferred policy acquisition costs and present value of future profits, change included in realized gains		1	3	3	6
Deferred policy acquisition costs and present value of future profits, change in unrealized		(294)	116	(589)	324
Deferred policy acquisition costs and present value of future profits, ending balance		873	1,284	873	1,284
Excluding Unrealized Gains | Annuity and Other
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Deferred policy acquisition costs and present value of future profits, beginning balance		1,460	1,352	1,413	1,368
Deferred policy acquisition costs and present value of future profits, change in unrealized		0	0	0	0
Deferred policy acquisition costs and present value of future profits, ending balance		$ 1,492	$ 1,382	$ 1,492	$ 1,382

[1] Adjustments to DPAC related to net unrealized gains/losses on securities and cash flow hedges.