Investments and Derivative Instruments (Details 8) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	$ 5,707	$ 5,598
Percent of Total	100.00%	100.00%
East North Central [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	181	187
Percent of Total	3.20%	3.30%
Middle Atlantic [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	408	409
Percent of Total	7.10%	7.30%
Mountain [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	104	104
Percent of Total	1.80%	1.90%
New England [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	383	353
Percent of Total	6.70%	6.30%
Pacific [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	1,543	1,587
Percent of Total	27.00%	28.30%
South Atlantic [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	1,025	899
Percent of Total	18.00%	16.10%
West North Central [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	46	47
Percent of Total	0.80%	0.80%
West South Central [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	338	338
Percent of Total	5.90%	6.00%
Other [Member]
Schedule of Available-for-sale Securities Mortgage Loans [Line Items]
Carrying Value	$ 1,679	$ 1,674
Percent of Total	29.50%	30.00%