Deferred Policy Acquisition Costs - Progression of deferred policy acquisition costs (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 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		$ 1,682	$ 1,216
Deferred policy acquisition costs and present value of future profits, additions		252	219
Deferred policy acquisition costs and present value of future profits, periodic amortization		(195)	(230)
Deferred policy acquisition costs and present value of future profits, change included in realized gains		2	3
Deferred policy acquisition costs and present value of future profits, foreign currency translation		1	1
Deferred policy acquisition costs and present value of future profits, change in unrealized		(295)	208
Deferred policy acquisition costs and present value of future profits, ending balance		1,447	1,417
P&C
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		299	270
Deferred policy acquisition costs, additions		187	162
Deferred policy acquisition costs, periodic amortization		(175)	(154)
Deferred policy acquisition costs, foreign currency translation		1	1
Deferred policy acquisition costs, ending balance		312	279
Annuity and Other
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		1,285	1,217
Deferred policy acquisition costs, additions		64	57
Deferred policy acquisition costs, periodic amortization		(15)	(69)
Deferred policy acquisition costs, change included in realized gains		2	3
Deferred policy acquisition costs, ending balance		1,336	1,208
Movement in Deferred Sales Inducements [Roll Forward]
Deferred sales inducements, beginning balance		86	102
Deferred sales inducements, additions		1	0
Deferred sales inducements, periodic amortization		(3)	(5)
Deferred sales inducements, change included in realized gains		0	0
Deferred sales inducements, ending balance		84	97
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present value of future profits, beginning balance		42	49
Present value of future profits, periodic amortization		(2)	(2)
Present value of future profits, ending balance		40	47
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]	(30)	(422)
Unrealized investment gains (losses), change in unrealized	[1]	(295)	208
Unrealized investment gains (losses), ending balance	[1]	(325)	(214)
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		1,383	946
Deferred policy acquisition costs and present value of future profits, additions		65	57
Deferred policy acquisition costs and present value of future profits, periodic amortization		(20)	(76)
Deferred policy acquisition costs and present value of future profits, change included in realized gains		2	3
Deferred policy acquisition costs and present value of future profits, change in unrealized		(295)	208
Deferred policy acquisition costs and present value of future profits, ending balance		1,135	1,138
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		1,413	1,368
Deferred policy acquisition costs and present value of future profits, change in unrealized		0	0
Deferred policy acquisition costs and present value of future profits, ending balance		$ 1,460	$ 1,352

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