Summary of Significant Accounting Policies (Life Settlement Contracts) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Number of life settlement contracts	841
Fair value of life settlement contracts	$ 117
Face amount of life insurance policies	535
One Year from Balance Sheet Date [Member]
Number of life settlement contracts	70
Fair value of life settlement contracts	16
Face amount of life insurance policies	46
More than One and within Two Years from Balance Sheet Date [Member]
Number of life settlement contracts	70
Fair value of life settlement contracts	14
Face amount of life insurance policies	42
More than Two and within Three Years from Balance Sheet Date [Member]
Number of life settlement contracts	60
Fair value of life settlement contracts	12
Face amount of life insurance policies	39
More than Three and within Four Years from Balance Sheet Date [Member]
Number of life settlement contracts	60
Fair value of life settlement contracts	10
Face amount of life insurance policies	37
More than Four and within Five Years from Balance Sheet Date [Member]
Number of life settlement contracts	50
Fair value of life settlement contracts	9
Face amount of life insurance policies	33
More than Five Years from Balance Sheet Date and Thereafter [Member]
Number of life settlement contracts	531
Fair value of life settlement contracts	56
Face amount of life insurance policies	$ 338