Basis of Presentation and Accounting Policies - Narrative (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended
	Oct. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Allowance for doubtful accounts		$ 14.4		$ 15.2
Allowance for certain customer returns, rebates and incentives		$ 9.4		8.1
Antidilutive share-based compensation awards (in shares)		0.2	2.4
Capital expenditures in accounts payable or other current liabilities at period end		$ 21.5	$ 10.9
Outstanding purchase of common stock recorded in accounts payable		4.2	$ 3.5
Operating lease right-of-use assets		$ 341.4		$ 342.9
Accounting Standards Update 2016-02
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Operating lease right-of-use assets	$ 316.0
Operating lease liability	329.0
Accumulated other comprehensive loss
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reclassification from AOCI to retained earnings	$ 147.0