Derivative Instruments and Other Financial Instruments Used For Hedging (Details 4) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Trading Derivatives
Trading account activities	$ (3)	$ 40	$ (7)	$ 68
Trading Derivatives
Trading Derivatives
Trading account activities	(24)	33	(36)	33
Trading Derivatives | Interest rate derivative contracts
Trading Derivatives
Trading account activities	(36)	22	(58)	13
Trading Derivatives | Equity
Trading Derivatives
Trading account activities	0	(1)	0	(1)
Trading Derivatives | Foreign exchange derivative contracts
Trading Derivatives
Trading account activities	11	11	21	20
Trading Derivatives | Commodity
Trading Derivatives
Trading account activities	$ 1	$ 1	$ 1	$ 1