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
	Mar. 31, 2021 USD ($) Contract	Mar. 31, 2020 USD ($) Contract
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Exercised contracts | Contract	25	33
Realized gains (losses) on the matured, expired or settled contracts	$ (1)	$ 4
Unrealized gains on the change in fair value of outstanding contracts	$ 38	$ 47