Reserve for Life-Contingent Contract Benefits and Contractholder Funds (Details 6) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	$ 366	$ 350	$ 555
In the event of death | Variable annuities
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	105	96	98
At annuitization (includes income benefit guarantees) | Variable annuities
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	65	92	99
Accumulation at specified dates | Variable annuities
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	38	32	43
For cumulative periodic withdrawals | Variable annuities
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	14	13	13
Other Guarantees [Member] | Variable annuities
Liabilities for guarantees:
Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross	$ 144	$ 117	$ 302