Investments in Fixed Maturity Securities (Narrative) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]
Held-to-maturity Securities, Restricted	$ 1,022
Minimum ownership of Common stockholders equity	10.00%
Insurance-related Assessments [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]
Held-to-maturity Securities, Restricted	$ 178
Reinsurance
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]
Held-to-maturity Securities, Restricted	43
Letters of Credit Outstanding, Amount	$ 18