Derivatives - Cash Flow Hedges - Effective and Ineffective Portions (Details) - Cash flow hedge $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	$ 133
Pretax Gain (Loss) Recognized in Income on Effective Portion of Derivative as a Result of Reclassification from Accumulated Other Comprehensive Income	(96)
Foreign currency exchange contracts
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	151
Foreign currency exchange contracts | Cost of sales
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Income on Effective Portion of Derivative as a Result of Reclassification from Accumulated Other Comprehensive Income	(95)
Interest rate contracts
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	(18)
Interest rate contracts | Interest expense
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Income on Effective Portion of Derivative as a Result of Reclassification from Accumulated Other Comprehensive Income	$ (1)