Derivative instruments (Details Textual) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net cash provided by operating activities		$ 8,344	$ 6,636
Foreign currency and cross currency swap contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amounts expected to be reclassified from AOCI into earnings over the next 12 months, foreign currency and cross-currency swaps		34
Derivatives designated as hedging instrument [Member] | Foreign currency forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount		4,800		$ 5,000
Derivatives designated as hedging instrument [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount		7,400		9,600
Value of derivative contracts terminated		2,200
Value of derivative contracts terminated resulting in net cash provided by operating activities		5,200
Net cash provided by operating activities	$ 576	576
Derivatives not designated as hedging instrument [Member] | Foreign currency forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount		1,000		1,200
Interest Expense, Net [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized from termination of contracts		17
Long-term debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Liability, Fair Value Hedge		7,782		$ 8,814
Long-term debt [Member] | Interest Rate Swap, At-Then Current Interest Rates [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Liability, Fair Value Hedge		$ 5,200