Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) - Income Approach Valuation Technique [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fixed maturity securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 142	$ 138
Fixed maturity securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	0.00%	3.00%
Fixed maturity securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	20.00%	184.00%
Fixed maturity securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	4.00%	6.00%
Life settlement contracts, included in Other assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 72	$ 74
Life settlement contracts, included in Other assets [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	55.00%	55.00%
Life settlement contracts, included in Other assets [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	1676.00%	1676.00%
Life settlement contracts, included in Other assets [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	164.00%	164.00%
Life settlement contracts, included in Other assets [Member] | Rate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate risk premium	9.00%	9.00%