v3.10.0.1
Derivative Instruments - Derivatives in Accumulated Other Comprehensive Income (Details) - Foreign Exchange Contract - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Effect of derivative Contracts on Accumulated Other Comprehensive Income        
Amount of Gain (Loss) Reclassified From AOCI to Earnings $ 14 $ (13) $ (33) $ 14
Designated as Hedging Instrument | Cash Flow Hedging        
Effect of derivative Contracts on Accumulated Other Comprehensive Income        
Beginning balance     (57) 54
Amount of Gain (Loss) Recognized in Other Comprehensive Income     54 (94)
Amount of Gain (Loss) Reclassified From AOCI to Earnings     (37) 28
Ending balance $ 34 $ (68) $ 34 $ (68)