Short-term Debt - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Short-term debt	$ 641.0	$ 509.7
Commercial Paper
Debt Instrument [Line Items]
Short-term debt	$ 617.0	$ 484.0
Debt, weighted average interest rate	0.49%	0.18%
Interest Bearing Loan
Debt Instrument [Line Items]
Short-term debt	$ 23.5	$ 23.5

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant