Derivative Financial Instruments (Details 2) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Asset derivatives
Asset derivatives gross amount	$ 105	$ 121
Asset derivatives, gross liability	(13)	(28)
Derivative assets net amount on balance sheet	92	93
Liability derivatives
Liability derivatives gross amount	(349)	(334)
Liability derivatives, gross asset	6	0
Derivative liabilities net amount on balance sheet	(343)	(334)
OTC derivatives
Asset derivatives
Asset derivatives gross amount	12	31
Asset derivatives, gross liability	(19)	(28)
Derivative, collateral, right to reclaim cash	10	19
Derivative assets net amount on balance sheet	3	22
Derivative assets received under securities collateral	0	(9)
Derivative asset, fair value, amount offset against collateral	3	13
Liability derivatives
Liability derivatives gross amount	(28)	(33)
Liability derivatives, gross asset	19	28
Derivative liability offsets under cash collateral pledged	2	0
Derivative liabilities net amount on balance sheet	(7)	(5)
Derivative liabilities received under securities collateral	3	4
Derivative liability, fair value, amount offset against collateral	$ (4)	$ (1)