Reserve for Life-Contingent Contract Benefits and Contractholder Funds (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	12,380	$ 12,386
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Premium deficiency reserve	(28)
Structured settlement annuities
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	6,682	6,645
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	2,250	2,283
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	2,521	2,542
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	830	816
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)	7.00%
Other
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	97	$ 100
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)	2.60%
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%