Hedging transactions and derivative financial instruments Hedging transactions and derivative financial instruments (Derivative and Nonderivative Debt Instruments) (Details) - Net investment hedging - USD ($) $ in Millions		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 26	$ 0
Accrued expenses and other liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	112	622
Long-term debt
Derivatives, Fair Value [Line Items]
Nonderivative hedging instruments	$ 6,276	$ 4,573