Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Recognition of premium revenues and contract charges, and related benefits and interest credited
Valuation allowance for uncollectible premium installment receivables	$ 90	$ 83
Securities loaned
Cash collateral received as percentage of fair value of domestic securities loaned	102.00%
Cash collateral received as a percent of fair value of foreign securities loaned	105.00%
Deferred Policy Acquisition and Sales Inducement Costs
Present value of future profits	$ 58	66
Amortization expense of present value of future profits	$ 8	$ 13	$ 16
Minimum
Deferred Policy Acquisition and Sales Inducement Costs
Property-liability policies, term for deferment and recognition of premiums	6 months
Period for amortization of DAC for property-liability insurance	6 months
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	15 years
Maximum
Securities loaned
Securities lending transactions length	30 days
Deferred Policy Acquisition and Sales Inducement Costs
Property-liability policies, term for deferment and recognition of premiums	12 months
Period for amortization of DAC for property-liability insurance	12 months
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	30 years
Interest-sensitive life insurance | Minimum
Deferred Policy Acquisition and Sales Inducement Costs
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	10 years
Interest-sensitive life insurance | Maximum
Deferred Policy Acquisition and Sales Inducement Costs
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	20 years
Fixed annuities | Minimum
Deferred Policy Acquisition and Sales Inducement Costs
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	5 years
Fixed annuities | Maximum
Deferred Policy Acquisition and Sales Inducement Costs
Period for amortization of DAC and DSI for interest-sensitive life, fixed annuities and other investment contracts	10 years