Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Leases [Abstract]
Operating lease expense	$ 80.1
Rent expense under operating leases		$ 87.0	$ 82.7
Use of cash for payments on operating leases	90.0
ROU asset additions	110.0
Expected lease payments for operating leases that have not yet commenced	60.0
Interest income on lease receivables	71.2
Lease payments collected during the period	162.8	171.6	182.7
Reduction in lease receivable balance	$ 91.6	$ 94.6	$ 97.4