Postretirement Benefit Plans - Summary of PME Multi-Employer Plan (Detail) - PME Multiemployer Plan [Member] $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) employee	Dec. 31, 2019 USD ($) employee	Dec. 31, 2018 USD ($) employee
Multiemployer Plans [Line Items]
NXP’s contributions to the plan	$ 33	$ 31	$ 34
Employee contributions	$ 4	$ 4	$ 4
Average number of NXP’s active employees participating in the plan | employee	2,048	2,129	2,183