Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Sep. 30, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	$ 146.1	$ 118.2
Other liabilities		51.0
Total Liabilities at Fair Value	37.6	94.8
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0	0
Other liabilities		0
Total Liabilities at Fair Value	0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	146.1	118.2
Other liabilities		0
Total Liabilities at Fair Value	37.6	43.8
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0	0
Other liabilities		51.0
Total Liabilities at Fair Value	0	51.0
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities	0	51.0
Interest rate management contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	53.0	48.2
Derivative liabilities	14.1	6.0
Interest rate management contract [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest rate management contract [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	53.0	48.2
Derivative liabilities	14.1	6.0
Interest rate management contract [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest rate management contract [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	53.0	48.2
Derivative liabilities	14.1	6.0
Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	93.1	70.0
Derivative liabilities	23.5	37.8
Forward Exchange Contracts [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Forward Exchange Contracts [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	93.1	70.0
Derivative liabilities	23.5	37.8
Forward Exchange Contracts [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Forward Exchange Contracts [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	93.1	70.0
Derivative liabilities	$ 23.5	$ 37.8