Fair Value Measurements Level 4 Credit Standing Adjustments and Behavior Risk Margins (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (31)	$ (3)
Credit Standing Adjustment	2		$ 0
Credit standing adjustment assumption net of reinsurance [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	0
Gain (Loss) Due to Changes in Assumptions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative, Gain (Loss) on Derivative, Net		0
GMWB Derivatives, Net [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Behavior Risk Margin	45		$ 0
GMWB Derivatives, Net [Member] \| Behavior Risk Margin Update Due to Underlying Fund Performance [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (4)	$ 10