Derivative Financial Instruments and Off-balance sheet Financial Instruments (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Asset derivatives
Gross amount	$ 121	$ 63
Derivative asset, fair value, gross liability	(28)	(2)
Net amount on balance sheet	93	61
Liability derivatives
Gross amount	(334)	(329)
Liability derivatives, Gross asset	0	6
Net amount on balance sheet	(334)	(323)
OTC derivatives
Asset derivatives
Gross amount	31	21
Derivative asset, fair value, gross liability	(28)	(8)
Derivative asser cash received pledged		(5)
Derivative asset offsets under cash collateral pledged	19
Net amount on balance sheet	22	8
Securities collateral (received) pledged	(9)	(4)
Net amount	13	4
Liability derivatives
Gross amount	(33)	(25)
Liability derivatives, Gross asset	28	8
Derivative liability offsets under cash collateral pledged	0	(1)
Net amount on balance sheet	(5)	(18)
Securities collateral (received) pledged	4	9
Net amount	$ (1)	$ (9)