Taxes on Earnings - Schedule of Effective Income Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 28, 2018	Dec. 29, 2017	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Federal statutory income tax rate			24.60%	35.00%	35.00%
Impact of U.S. Tax Reform			46.30%	0.00%	0.00%
State and local taxes, net of federal tax benefit			0.50%	0.90%	0.20%
Non-U.S. income taxed at different rates, net			(0.60%)	(8.40%)	(9.30%)
Resolution of tax contingencies to due to expiration of statutes of limitation			(2.50%)	(1.70%)	(1.20%)
Change in acquirer's deferred taxes related to purchase accounting			(1.80%)	0.00%	0.00%
Excess stock deduction			(1.50%)	(0.00%)	(0.00%)
Other			1.80%	(0.40%)	0.80%
Effective tax rate			66.80%	25.40%	25.50%
Provisional tax expense related top re-measuring net deferred tax assets			$ 43.2
Provisional tax expense related to one-time transition tax	$ (7.1)	$ 207.1	164.6
Tax benefit related to excess stock deduction activity			$ 6.9