Fair Value Measurements (Details) - Reconciliation of Items Carried at Fair Value Using Significant Unobservable Inputs (Level 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013 Acquisition Contingent Consideration Payable [Member]	Sep. 30, 2012 Acquisition Contingent Consideration Payable [Member]	Sep. 30, 2012 Investments in Unconsolidated Affiliates [Member]	Sep. 30, 2011 Investments in Unconsolidated Affiliates [Member]
Beginning balance	$ (116.4)	$ 0	$ 9.3	$ 21.3
Gain (loss) included in:
Other income (expense) - other	0	0	(0.7)	(2.1)
Other comprehensive income	0	0	0	0.1
Issuances	0	(88.9)	0	0
Accretion (interest and fair value adjustment)	(35.0)	(27.5)	0.6	2.2
Settlements	45.0	0	(9.2)	(12.2)
Ending balance	(106.4)	(116.4)	0	9.3
Net change in unrealized gain (loss) included in earnings related to instruments still held	$ 0	$ 0	$ 0	$ (2.1)