Derivative instruments (Fair Value of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets
Total derivative assets, fair value	$ 474	$ 549
Liabilities
Total derivative liabilities, fair value	685	346
Derivatives designated as hedging instrument [Member]
Assets
Total derivative assets, fair value	474	548
Liabilities
Total derivative liabilities, fair value	685	346
Derivatives designated as hedging instrument [Member] | Foreign currency contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	375	223
Derivatives designated as hedging instrument [Member] | Foreign currency contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	5	31
Derivatives designated as hedging instrument [Member] | Cross-currency swap contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	10	66
Derivatives designated as hedging instrument [Member] | Cross-currency swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	657	315
Derivatives designated as hedging instrument [Member] | Interest rate swap contracts [Member] | Other current assets/Other assets [Member]
Assets
Total derivative assets, fair value	89	259
Derivatives designated as hedging instrument [Member] | Interest rate swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member]
Liabilities
Total derivative liabilities, fair value	23	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