Financial Instruments and Fair Value Measurements - Summary of Undesignated Financial Instruments Exercised and Realized and Unrealized Gains (Losses) in Foreign Currency and Derivative Gains (Losses) Net (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) Contract	Jun. 30, 2020 USD ($) Contract	Jun. 30, 2021 USD ($) Contract	Jun. 30, 2020 USD ($) Contract
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Exercised contracts | Contract	49	40	74	73
Realized gains (losses) on the matured, expired or settled contracts	$ (8)	$ 6	$ (9)	$ 10
Unrealized gains (losses) on the change in fair value of outstanding contracts	$ 2	$ (13)	$ 40	$ 34