Derivative instruments (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net cash provided by operating activities	$ 2,134	$ 1,845
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	(162)
Derivatives designated as hedging instrument [Member] | Foreign currency forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount	4,900		$ 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
Derivatives not designated as hedging instrument [Member] | Foreign currency forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount	800		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	7,784		$ 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