Derivatives (Net Derivative Gains Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Components of Net Derivatives Gains (Losses)
Derivatives and hedging gains (losses)	$ 2,504	$ 848
Embedded derivatives gains (losses)	(1,169)	(27)
Total net derivative gains (losses)	$ 1,335	$ 821