Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income	$ 143	$ 122
Denominator:
Shares used in net income per common share – basic	55.6	55.3
Effect of dilutive securities	0.2	0.3
Shares used in net income per common share – diluted	55.8	55.6
Net income per common share:
Basic	$ 2.58	$ 2.21
Diluted	$ 2.57	$ 2.20