Derivatives - Cash Flow Hedges - Effective and Ineffective Portions (Details) - Cash flow hedge $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	$ (82)
Pretax Gain (Loss) Recognized in Income on Effective Portion of Derivative as a Result of Reclassification from Accumulated Other Comprehensive Income	(34)
Foreign currency forward/option contracts
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	(79)
Foreign currency forward/option 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	(34)
Interest rate swap contracts
Derivatives in Cash Flow Hedging Relationships
Pretax Gain (Loss) Recognized in Other Comprehensive Income on Effective Portion of Derivative	$ (3)