Acquisitions and Divestitures Definite-lived intangible assets acquired (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 1,209.3	$ 1,182.2
Finite-Lived Intangible Assets, Accumulated Amortization	558.9	371.0
Finite-Lived Intangible Assets, Net	650.4	811.2
Acquired and reacquired rights
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,102.7	1,081.7
Finite-Lived Intangible Assets, Accumulated Amortization	496.1	320.1
Finite-Lived Intangible Assets, Net	$ 606.6	$ 761.6