Fair Value Measurements (Details 1) (Embedded derivatives [Member])	9 Months Ended
	Sep. 30, 2012
Unobservable inputs used by management in determining fair value of embedded derivatives
Risk margin for uncertainty in cash flows	0.30%
Minimum [Member]
Unobservable inputs used by management in determining fair value of embedded derivatives
Adjustment for insurance subsidiary's credit risk	0.50%
Surrenders	4.00%
Partial surrenders	3.00%
Annuitizations	1.00%
Deaths	1.00%
Budgeted option costs	2.50%
Maximum [Member]
Unobservable inputs used by management in determining fair value of embedded derivatives
Adjustment for insurance subsidiary's credit risk	2.05%
Surrenders	25.00%
Partial surrenders	5.00%
Annuitizations	2.00%
Deaths	2.50%
Budgeted option costs	4.00%