Fair Value Measurements (Details 1) (Embedded derivatives [Member])	3 Months Ended
	Mar. 31, 2013
Unobservable inputs used by management in determining fair value of embedded derivatives
Risk margin for uncertainty in cash flows	0.40%
Minimum [Member]
Unobservable inputs used by management in determining fair value of embedded derivatives
Adjustment for insurance subsidiary's credit risk	0.30%
Surrenders	4.00%
Partial surrenders	2.00%
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	2.00%
Surrenders	20.00%
Partial surrenders	5.00%
Annuitizations	2.00%
Deaths	2.50%
Budgeted option costs	4.00%