Revisions of Condensed Consolidated Financial Statements Statement of Cashflows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Net income	$ 217.5	$ 167.8
Depreciation and amortization	94.0	87.8
Deferred Income Tax Expense (Benefit)	(19.7)	1.6
Net Change in Realized Gains and Losses Deferred as Cash Flow Hedges		0
Unrealized (gains) losses on derivative instruments	(5.2)	1.9
Other Noncash Income (Expense)	0.8	(1.6)
Scenario, Previously Reported [Member]
Net income		170.7
Depreciation and amortization		87.1
Net Change in Realized Gains and Losses Deferred as Cash Flow Hedges		1.9
Unrealized (gains) losses on derivative instruments		0
Other Noncash Income (Expense)		(3.8)
Restatement Adjustment [Member]
Net income		(2.9)
Depreciation and amortization		0.7
Net Change in Realized Gains and Losses Deferred as Cash Flow Hedges		(1.9)
Unrealized (gains) losses on derivative instruments		(1.9)
Other Noncash Income (Expense)		$ 2.2