Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
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	$ 1,055	$ 756	$ 1,184	$ 821
Deferred policy acquisition costs and present value of future profits, additions	197	184	402	352
Deferred policy acquisition costs and present value of future profits, periodic amortization	(168)	(195)	(334)	(360)
Deferred policy acquisition costs and present value of future profits, change included in realized gains	3	2	5	4
Deferred policy acquisition costs and present value of future profits, foreign currency translation	(1)	(1)	(1)	0
Deferred policy acquisition costs and present value of future profits, change in unrealized	(205)	219	(375)	148
Deferred policy acquisition costs and present value of future profits, ending balance	881	965	881	965
Property and Casualty Insurance [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance	224	217	226	221
Deferred policy acquisition costs, additions	139	137	271	258
Deferred policy acquisition costs, periodic amortization	(128)	(130)	(262)	(256)
Deferred policy acquisition costs, foreign currency translation	(1)	(1)	(1)	0
Deferred policy acquisition costs, ending balance	234	223	234	223
Annuity and Run-off Long-term Care and Life [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance	1,063	942	1,018	925
Deferred policy acquisition costs, additions	56	46	124	90
Deferred policy acquisition costs, periodic amortization	(32)	(55)	(57)	(84)
Deferred policy acquisition costs, change included in realized gains	2	1	4	3
Deferred policy acquisition costs, ending balance	1,089	934	1,089	934
Movement in Deferred Sales Inducements [Roll Forward]
Deferred sales inducements, beginning balance	119	128	119	132
Deferred sales inducements, additions	2	1	7	4
Deferred sales inducements, periodic amortization	(6)	(7)	(11)	(14)
Deferred sales inducements, change included in realized gains	1	1	1	1
Deferred sales inducements, ending balance	116	123	116	123
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present value of future profits, beginning balance	53	71	55	74
Present value of future profits, periodic amortization	(2)	(3)	(4)	(6)
Present value of future profits, ending balance	51	68	51	68
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	(404)	(602)	(234)	(531)
Unrealized investment gains (losses), change in unrealized	(205)	219	(375)	148
Unrealized investment gains (losses), ending balance	(609)	(383)	(609)	(383)
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	831	539	958	600
Deferred policy acquisition costs and present value of future profits, additions	58	47	131	94
Deferred policy acquisition costs and present value of future profits, periodic amortization	(40)	(65)	(72)	(104)
Deferred policy acquisition costs and present value of future profits, change included in realized gains	3	2	5	4
Deferred policy acquisition costs and present value of future profits, change in unrealized	(205)	219	(375)	148
Deferred policy acquisition costs and present value of future profits, ending balance	647	742	647	742
Excluding Unrealized Gains [Member] | Annuity and Run-off Long-term Care and Life [Member]
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	1,235	1,141	1,192	1,131
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	$ 1,256	$ 1,125	$ 1,256	$ 1,125