Investments - Declines in Fair Value, Fixed Maturities (Details) (Debt Securities [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Investment Grade [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, One Year or Less, Fair Value	$ 2,250
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Fair Value	256
Available For Sale Securities, Continuous Unrealized Loss Position, One Year or Less, Amortized Cost	2,317
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Amortized Cost	278
Available-for-sale Securities, Continuous Unrealized Loss Position, One Year or Less, Aggregate Losses	(67)
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Aggregate Losses	(22)
Investment Grade [Member] | One Year Or Less [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	599
Investment Grade [Member] | More Than One Year [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	72
Below Investment Grade [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, One Year or Less, Fair Value	237
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Fair Value	46
Available For Sale Securities, Continuous Unrealized Loss Position, One Year or Less, Amortized Cost	243
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Amortized Cost	50
Available-for-sale Securities, Continuous Unrealized Loss Position, One Year or Less, Aggregate Losses	(6)
Available-for-sale Securities, Continuous Unrealized Loss Position, More Than One Year, Aggregate Losses	$ (4)
Below Investment Grade [Member] | One Year Or Less [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	210
Below Investment Grade [Member] | More Than One Year [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	16