Investments and Derivative Instruments Level 4 Concentration of Credit Risk (Details) - Investment Geographic Region [Domain] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Mar. 31, 2013
Concentration of Credit Risk [Line Items]
Concentration Risk, Benchmark Description	greater than 10% of the Company’s stockholder’s equity
Derivative, Notional Amount	$ 49,064	$ 55,838	$ 55,838