Financial and Derivative Instruments - Effect of Netting Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting Assets [Abstract]
Derivative Asset, Gross Amount Recognized	$ 656	$ 3,685
Derivative Asset, Gross Amounts Offset	645	3,402
Derivative Asset, Net Amounts Presented	11	283
Derivative Asset, Gross Amounts Not Offset	0	0
Derivative Asset, Net Amount	11	283
Offsetting Liabilities [Abstract]
Derivative Liability, Gross Amount Recognized	719	3,414
Derivative Liability, Gross Amounts Offset	645	3,402
Derivative Liability, Net Amounts Presented	74	12
Derivative Liability, Gross Amounts Not Offset	0	0
Derivative Liability, Net Amount	$ 74	$ 12