Investments and Derivative Instruments (Details 10) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Mortgage Loans by Property Type
Mortgage loans, carrying value	$ 3,315	$ 3,470
Percent of Total	100.00%	100.00%
Agricultural [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	56	93
Percent of Total	1.70%	2.70%
Industrial [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	1,151	1,182
Percent of Total	34.70%	34.10%
Lodging [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	27	27
Percent of Total	0.80%	0.80%
Multifamily [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	559	576
Percent of Total	16.90%	16.60%
Office [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	683	723
Percent of Total	20.60%	20.80%
Retail [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	725	745
Percent of Total	21.90%	21.50%
Other [Member]
Mortgage Loans by Property Type
Mortgage loans, carrying value	$ 114	$ 124
Percent of Total	3.40%	3.50%