Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition
Retained earnings	$ 40,636				$ 39,115				$ 40,636	$ 39,115
Contract Balance
Current deferred income balances	617				513				617	513
Net Sales	$ 7,945	$ 8,152	$ 8,390	$ 8,278	$ 7,990	$ 8,172	$ 7,810	$ 7,685	32,765	$ 31,657	$ 30,109
Difference between Revenue Guidance in Effect before and after Topic 606 | Maximum
Revenue, Initial Application Period Cumulative Effect Transition
Retained earnings												$ 2
ASU 2014-09 Revenue from Contracts with Customers | Difference between Revenue Guidance in Effect before and after Topic 606
Contract Balance
Deferred income recognized as revenue									$ 500