Derivatives (Net Derivative Gains Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of Net Derivatives Gains (Losses)
Derivatives and hedging gains (losses)	$ (4,030)	$ (154)	$ 868
Embedded derivatives gains (losses)	(1,848)	(270)	(1,049)
Total net derivative gains (losses)	$ (5,878)	$ (424)	$ (181)