Reserve for Life-Contingent Contract Benefits and Contractholder Funds (Details) (USD $) In Millions, unless otherwise specified					12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Structured settlement annuities	Dec. 31, 2011 Structured settlement annuities	Dec. 31, 2012 Structured settlement annuities Minimum	Dec. 31, 2012 Structured settlement annuities Maximum	Dec. 31, 2012 Other immediate fixed annuities	Dec. 31, 2011 Other immediate fixed annuities	Dec. 31, 2012 Other immediate fixed annuities Minimum	Dec. 31, 2012 Other immediate fixed annuities Maximum	Dec. 31, 2012 Traditional life insurance	Dec. 31, 2011 Traditional life insurance	Dec. 31, 2012 Traditional life insurance Minimum	Dec. 31, 2012 Traditional life insurance Maximum	Dec. 31, 2012 Accident and health insurance	Dec. 31, 2011 Accident and health insurance	Dec. 31, 2012 Accident and health insurance Minimum	Dec. 31, 2012 Accident and health insurance Maximum	Dec. 31, 2012 Other	Dec. 31, 2011 Other	Dec. 31, 2012 Other Minimum	Dec. 31, 2012 Other Maximum
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 14,895	$ 14,406	$ 7,274	$ 7,075			$ 2,386	$ 2,350			$ 3,110	$ 3,004			$ 2,011	$ 1,859			$ 114	$ 118
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)					1.30%	9.20%			0.10%	11.50%			4.00%	11.30%			3.00%	7.00%			4.00%	5.80%
Premium deficiency reserve	$ (771)	$ (594)