Inventory - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Inventory [Line Items]
Inventory write-downs			$ 88	$ 88
Cost of Revenues [Member]
Inventory [Line Items]
Inventory write-downs	$ 35	$ 37	70	$ 82
Research and Development Expenses [Member]
Inventory [Line Items]
Inventory write-downs	$ 35		$ 70