Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 30, 2018	Mar. 31, 2017	Mar. 30, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
United States income taxes	$ 7.8	$ 51.7	$ 312.7	$ 108.2
Foreign income taxes	8.5	4.8	18.8	11.6
Provision for income taxes	$ 16.3	$ 56.5	$ 331.5	$ 119.8
Effective tax rate	5.60%	20.10%	48.90%	19.90%