Debt (Summary of Outstanding Debt) (Details) $ in Millions, ¥ in Billions		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Apr. 26, 2018 CNY (¥)
Debt Disclosure [Abstract]
Current portion of long-term debt due to related party		$ 37.8		$ 0.0
Short-term borrowings		58.2		54.3
Current portion of long-term debt	[1],[2]	40.4		406.6
Long-term debt		2,907.3		2,967.4
Long-term debt – related party		320.1	[2]	384.3	[2]	¥ 2.3
Total Debt		$ 3,326.0		$ 3,812.6

[1] Fiscal year 2019 includes the current portion of long-term debt owed to a related party of $37.8.

[2] Refer to Note 7, Acquisitions, for additional information regarding related party debt.