Leases (Minimum Lease Payments Expected to be Collected) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Minimum Lease Payments Expected to be Collected on Sales-type and Direct Financing Leases
2020 (excluding the six months ended 31 March 2020)	$ 79.7
2021	155.4
2022	144.7
2023	138.6
2024	132.6
Thereafter	715.7
Total	1,366.7
Unearned interest income	(436.1)
Lease Receivables, net	$ 930.6
Minimum Lease Payments Expected to be Collected Prior to Adoption of New Lease Guidance
2020		$ 162.5
2021		156.9
2022		145.7
2023		139.4
2024		133.2
Thereafter		715.5
Total		1,453.2
Unearned interest income		(472.3)
Lease Receivables, net		$ 980.9