Net Income Per Share - Reconciliation of Shares Used in Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ in Billions		3 Months Ended		9 Months Ended
	Sep. 17, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Basic (shares)		81,263,000	79,063,000	79,783,000	79,072,000
Assumed dilution under stock plans (shares)		384,000	299,000	332,000	281,000
Diluted (shares)		81,647,000	79,362,000	80,115,000	79,353,000
Public Offering
Subsidiary, Sale of Stock [Line Items]
Shares issued	12,667,947
Consideration received on transaction	$ 1.6