Sales and revenue contract information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Trade receivables from dealers and end users	$ 6,048		$ 6,048		$ 7,648	$ 7,743
Long term trade receivables from dealers and end users	674		674		693	674
Contract liabilities	1,659		1,659		$ 1,654	$ 1,680
Revenue recognized from contract liability balance at beginning of period	144	$ 101	843	$ 976
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations with an original contract duration greater than one year	$ 6,000		$ 6,000
Expected period of performance satisfaction	12 months		12 months
Twelve Months | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Unsatisfied performance obligations with an original contract duration greater than one year	$ 2,400		$ 2,400