Investments (Other Trading Account Assets) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Amortized Cost
Fair Value	8,665	6,453
Cash Equivalents And Short Term Investments [Member]
Amortized Cost	85	105
Fair Value	86	106
Fixed Maturities [Member]
Amortized Cost	6,265	4,653
Fair Value	6,361	4,723
Equity Securities [Member]
Amortized Cost	1,026	1,051
Fair Value	1,160	1,177
Other Assets [Member]
Amortized Cost	8	3
Fair Value	13	7
Derivative Financial Instruments, Assets [Member]
Fair Value	1,045	440
Investments Excluding Derivative Instruments [Member]
Amortized Cost	7,384	5,812
Fair Value	$ 7,620	$ 6,013