Derivative Financial Instruments and Off-balance sheet Financial Instruments (Details 2) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Asset derivatives
Gross amount	$ 63	$ 94
Derivative Asset, Fair Value, Gross Liability	(2)	(16)
Net amount on balance sheet	61	78
Liability derivatives
Gross amount	(329)	(367)
Liability derivatives, Gross asset	6	6
Net amount on balance sheet	(323)	(361)
OTC derivatives
Asset derivatives
Gross amount	21	12
Derivative Asset, Fair Value, Gross Liability	(8)	(22)
Derivative asset offsets under cash collateral received	(5)
Derivative asset offsets under cash collateral pledged		17
Net amount on balance sheet	8	7
Securities collateral (received) pledged	(4)	(4)
Net amount	4	3
Liability derivatives
Gross amount	(25)	(35)
Liability derivatives, Gross asset	8	22
Derivative liability offsets under cash collateral pledged	(1)	0
Net amount on balance sheet	(18)	(13)
Securities collateral (received) pledged	9	8
Net amount	$ 9	$ 5