Fair Value Measurements - Schedule of Assets and Liabilities at Fair Value (Details) - Fair Value Measurement, Recurring - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Other noncurrent assets
Total assets at fair value	$ 306.9	$ 43.9
Accrued expenses and other liabilities
Currency derivatives	0.1	5.2
Deferred compensation obligations	20.8	19.6
Total liabilities at fair value	20.9	24.8
Level 1
Other noncurrent assets
Total assets at fair value	19.6	0.4
Accrued expenses and other liabilities
Total liabilities at fair value	0.0	0.0
Level 2
Other noncurrent assets
Total assets at fair value	285.2	37.1
Accrued expenses and other liabilities
Currency derivatives	0.1	5.2
Total liabilities at fair value	0.1	5.2
Assets measured at NAV
Other noncurrent assets
Non-qualified trust funds	2.1	6.4
Accrued expenses and other liabilities
Deferred compensation obligations	20.8	19.6
Money market funds
Cash and cash equivalents
Cash and cash equivalents	0.6	0.4
Money market funds | Level 1
Cash and cash equivalents
Cash and cash equivalents	0.6	0.4
Time deposits
Cash and cash equivalents
Cash and cash equivalents	277.3	13.3
Time deposits | Level 2
Cash and cash equivalents
Cash and cash equivalents	277.3	13.3
Prepaid expenses and other current assets
Prepaid expenses and other current assets
Currency derivatives	0.1	6.0
Interest rate swap agreements	7.8	5.2
Prepaid expenses and other current assets | Level 2
Prepaid expenses and other current assets
Currency derivatives	0.1	6.0
Interest rate swap agreements	7.8	5.2
Other noncurrent assets
Prepaid expenses and other current assets
Interest rate swap agreements		12.6
Other noncurrent assets
Non-qualified trust funds	2.1	6.4
Deferred compensation investments	19.0
Other noncurrent assets | Level 1
Other noncurrent assets
Deferred compensation investments	19.0
Other noncurrent assets | Level 2
Prepaid expenses and other current assets
Interest rate swap agreements		12.6
Other noncurrent assets | Assets measured at NAV
Other noncurrent assets
Non-qualified trust funds	$ 2.1	$ 6.4