Investments and Derivative Instruments (Mortgage Loans by Property Type) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Mortgage Loans by Property Type
Carrying value	$ 5,598	$ 6,711
Percent of Total	100.00%	100.00%
Agricultural [Member]
Mortgage Loans by Property Type
Carrying value	125	142
Percent of Total	2.20%	2.10%
Industrial [Member]
Mortgage Loans by Property Type
Carrying value	1,718	2,079
Percent of Total	30.70%	30.90%
Lodging [Member]
Mortgage Loans by Property Type
Carrying value	27	81
Percent of Total	0.50%	1.20%
Multifamily [Member]
Mortgage Loans by Property Type
Carrying value	1,155	1,200
Percent of Total	20.60%	17.90%
Office [Member]
Mortgage Loans by Property Type
Carrying value	1,278	1,510
Percent of Total	22.80%	22.50%
Retail [Member]
Mortgage Loans by Property Type
Carrying value	1,140	1,460
Percent of Total	20.40%	21.80%
Other [Member]
Mortgage Loans by Property Type
Carrying value	$ 155	$ 239
Percent of Total	2.80%	3.60%