Sales and revenue contract information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Trade receivables from dealers and end users	$ 7,156	$ 7,156	$ 7,743
Long term trade receivables from dealers and end users	670	670	674
Long-term customer advances	519	519	$ 437
Revenue recognized from contract liability balance at beginning of period	101	976
Unsatisfied performance obligations with an original contract duration greater than one year	6,100	6,100
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations with an original contract duration greater than one year	$ 2,400	$ 2,400