Financial and Derivative Instruments Financial and Derivative Instruments (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Offsetting Assets [Abstract]
Derivative Asset, Gross Amount Recognized	$ 1,052	$ 2,459
Derivative Asset, Gross Amounts Offset	1,020	2,254
Derivative Asset, Net Amounts Presented	32	205
Derivative Asset, Gross Amounts Not Offset	0	0
Derivative Asset, Net Amount	32	205
Offsetting Liabilities [Abstract]
Derivative Liability, Gross Amount Recognized	1,129	2,307
Derivative Liability, Gross Amounts Offset	1,020	2,254
Derivative Liability, Net Amounts Presented	109	53
Derivative Liability, Gross Amounts Not Offset	0	0
Derivative Liability, Net Amount	$ 109	$ 53