Fair Value Measurements (Details 2) (Level 3 [Member])	3 Months Ended
	Mar. 31, 2012
Withdrawal Utilization [Member]
Fair Value Inputs [Abstract]
Positive or negative relationship of change in input to change in fair value measurement	Increase
Withdrawal Utilization [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	100.00%
Withdrawal Utilization [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	20.00%
Withdrawal Rates [Member]
Fair Value Inputs [Abstract]
Positive or negative relationship of change in input to change in fair value measurement	Increase
Withdrawal Rates [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	8.00%
Withdrawal Rates [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	0.00%
Lapse Rates [Member]
Fair Value Inputs [Abstract]
Positive or negative relationship of change in input to change in fair value measurement	Decrease
Lapse Rates [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	75.00%
Lapse Rates [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	0.00%
Reset Elections [Member]
Fair Value Inputs [Abstract]
Positive or negative relationship of change in input to change in fair value measurement	Increase
Reset Elections [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	75.00%
Reset Elections [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	20.00%
Equity Volatility [Member]
Fair Value Inputs [Abstract]
Positive or negative relationship of change in input to change in fair value measurement	Increase
Equity Volatility [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	50.00%
Equity Volatility [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Range of Values-Unobservable Inputs	10.00%