Business Segment Information (Reconciliation of Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Total assets	$ 17,853.8	$ 18,028.6
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Assets of discontinued operations	9.8	1,968.5
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	17,844.0	16,060.1
Segment Reconciling Items [Member] | Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Assets of discontinued operations	$ 9.8	$ 1,968.5