Investments and Derivative Instruments (Details 9) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Mortgage Loans by Property Type
Carrying Value	$ 5,707	$ 5,598
Percent of Total	100.00%	100.00%
Agricultural [Member]
Mortgage Loans by Property Type
Carrying Value	89	125
Percent of Total	1.60%	2.20%
Industrial [Member]
Mortgage Loans by Property Type
Carrying Value	1,721	1,718
Percent of Total	30.10%	30.70%
Lodging [Member]
Mortgage Loans by Property Type
Carrying Value	27	27
Percent of Total	0.50%	0.50%
Multifamily [Member]
Mortgage Loans by Property Type
Carrying Value	1,241	1,155
Percent of Total	21.70%	20.60%
Office [Member]
Mortgage Loans by Property Type
Carrying Value	1,373	1,278
Percent of Total	24.10%	22.80%
Retail [Member]
Mortgage Loans by Property Type
Carrying Value	1,104	1,140
Percent of Total	19.30%	20.40%
Other [Member]
Mortgage Loans by Property Type
Carrying Value	$ 152	$ 155
Percent of Total	2.70%	2.80%