Reserve for Life-Contingent Contract Benefits and Contractholder Funds (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 11,394	$ 11,566
Structured settlement annuities
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 6,673	6,682
Structured settlement annuities | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	2.70%
Structured settlement annuities | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	9.00%
Other immediate fixed annuities
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 2,035	2,246
Other immediate fixed annuities | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	0.00%
Other immediate fixed annuities | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	11.50%
Traditional life insurance
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 2,347	2,303
Traditional life insurance | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	2.50%
Traditional life insurance | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	11.30%
Accident and health insurance
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 234	238
Accident and health insurance | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	3.00%
Accident and health insurance | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	6.00%
Other
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 105	$ 97
Other | Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	2.10%
Other | Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	5.80%