Fair Value Measurements Significant Unobservable Inputs (Details) (Investment contract guarantees)	9 Months Ended
	Sep. 30, 2012
Minimum | GMAB / GMWB / GMWBL
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Long-term equity implied volatility	15.00%
Funds	(20.00%)
Rates and Equity	(45.00%)
Nonperformance Risk	0.25%
Actuarial Assumptions, Benefit Utilization	0.00%
Actuarial Assumptions, Partial Withdrawals	0.00%
Actuarial Assumptions, Lapses	0.00%
Minimum | Fixed Indexed Annuities (FIA)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Long-term equity implied volatility	0.00%
Funds	0.00%
Rates and Equity	0.00%
Nonperformance Risk	0.25%
Actuarial Assumptions, Benefit Utilization	0.00%
Actuarial Assumptions, Partial Withdrawals	0.00%
Actuarial Assumptions, Lapses	0.00%
Maximum | GMAB / GMWB / GMWBL
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Long-term equity implied volatility	25.00%
Funds	98.00%
Rates and Equity	5.00%
Nonperformance Risk	3.50%
Actuarial Assumptions, Benefit Utilization	85.00%
Actuarial Assumptions, Partial Withdrawals	10.00%
Actuarial Assumptions, Lapses	40.00%
Maximum | Fixed Indexed Annuities (FIA)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Long-term equity implied volatility	0.00%
Funds	0.00%
Rates and Equity	0.00%
Nonperformance Risk	3.50%
Actuarial Assumptions, Benefit Utilization	0.00%
Actuarial Assumptions, Partial Withdrawals	0.00%
Actuarial Assumptions, Lapses	10.00%