Segment Information and Geographic Data - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Reportable segments | segment	2	2
Operating expenses	$ (1,408)	$ (1,371)	$ (1,388)
Customer A | Customer Concentration Risk | Accounts Receivable
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	16.80%	23.00%
Customer B | Customer Concentration Risk | Accounts Receivable
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	7.80%	16.90%
Customer C | Customer Concentration Risk | Accounts Receivable
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	20.60%	14.60%
AIT | Operating segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating expenses			$ 14