Derivative instruments (Fair Value of Derivatives) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets
Total derivative assets, fair value	$ 344	$ 549
Liabilities
Total derivative liabilities, fair value	573	346
Derivatives designated as hedging instrument [Member]
Assets
Total derivative assets, fair value	344	548
Liabilities
Total derivative liabilities, fair value	573	346
Derivatives designated as hedging instrument [Member] | Foreign currency contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	111	223
Derivatives designated as hedging instrument [Member] | Foreign currency contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	88	31
Derivatives designated as hedging instrument [Member] | Cross-currency swap contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	124	66
Derivatives designated as hedging instrument [Member] | Cross-currency swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	481	315
Derivatives designated as hedging instrument [Member] | Interest rate swap contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	109	259
Derivatives designated as hedging instrument [Member] | Interest rate swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	4	0
Derivatives not designated as hedging instrument [Member]
Assets
Total derivative assets, fair value	0	1
Liabilities
Total derivative liabilities, fair value	0	0
Derivatives not designated as hedging instrument [Member] | Foreign currency contracts [Member] | Other current assets [Member]
Assets
Total derivative assets, fair value	0	1
Derivatives not designated as hedging instrument [Member] | Foreign currency contracts [Member] | Accrued liabilities [Member]
Liabilities
Total derivative liabilities, fair value	$ 0	$ 0