Financial Instruments, Derivatives and Hedging Activities - Foreign currency hedging (Details) - Foreign Currency Forward Contracts - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Short | Not Designated as Hedging Instrument
Financial instruments, derivatives and hedging activities
Derivative notional amount	$ 487	$ 410
Long | Not Designated as Hedging Instrument
Financial instruments, derivatives and hedging activities
Derivative notional amount	276	224
Cash Flow Hedging | Short | Designated as Hedging Instrument
Financial instruments, derivatives and hedging activities
Derivative notional amount	256	401
Cash Flow Hedging | Long | Designated as Hedging Instrument
Financial instruments, derivatives and hedging activities
Derivative notional amount	$ 422	$ 542