Financial and Derivative Instruments (Details 2) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Offsetting Assets [Abstract]
Derivative Assets, Gross Amount Recognized	$ 3,399	$ 1,169
Derivative Assets, Gross Amounts Offset	3,383	1,147
Derivative Assets, Net Amounts Presented	16	22
Derivative Assets, Gross Amounts Not Offset	9	0
Derivative Assets, Net Amounts Presented	7	22
Offsetting Liabilities [Abstract]
Derivative Liabilities, Gross Amount Recognized	3,467	1,271
Derivative Liabilities, Gross Amounts Offset	3,383	1,147
Derivative Liabilities, Net Amounts Presented	84	124
Derivative Liabilities, Gross Amounts Not Offset	9	0
Derivative Liabilities, Net Amounts Presented	$ 75	$ 124