Employee Stock Plans - Activity for Restricted Stock Restricted Stock Units and Performance Units (Detail) shares in Millions	12 Months Ended
	Sep. 27, 2019 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	0.8
Granted (in shares) | shares	0.3
Vested (in shares) | shares	(0.3)
Cancelled or expired (in shares) | shares	(0.1)
Ending balance (in shares) | shares	0.7
Weighted Average Grant-Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 89.17
Granted (in dollars per share) | $ / shares	124.73
Vested (in dollars per share) | $ / shares	82.38
Canceled or expired (in dollars per share) | $ / shares	91.30
Ending balance (in dollars per share) | $ / shares	$ 108.35