Acquisitions (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Jul. 13, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Upward adjustment	$ 200.0
General and administrative expenses		$ 83.6	$ 82.6	$ 183.0	$ 162.2
Spectrum Merger [Member]
Business Acquisition [Line Items]
General and administrative expenses			$ 16.1		$ 18.9
SBH Common Stock [Member] | HRG [Member]
Business Acquisition [Line Items]
Par value	$ 0.01