Fair Value Measurements (Schedule of Recurring Fair Value Measurements) (Details) - Fair Value [Member] - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016
Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	$ 229.4	$ 193.8
Derivative liabilities	194.0	82.6
Interest Rate Management Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	234.9	179.9
Derivative liabilities	15.1	12.7
Recurring Basis [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	464.3	373.7
Total Liabilities at Fair Value	209.1	95.3
Recurring Basis [Member] | Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	229.4	193.8
Derivative liabilities	194.0	82.6
Recurring Basis [Member] | Interest Rate Management Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	234.9	179.9
Derivative liabilities	15.1	12.7
Recurring Basis [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Recurring Basis [Member] | Level 1 [Member] | Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Recurring Basis [Member] | Level 1 [Member] | Interest Rate Management Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Recurring Basis [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	464.3	373.7
Total Liabilities at Fair Value	209.1	95.3
Recurring Basis [Member] | Level 2 [Member] | Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	229.4	193.8
Derivative liabilities	194.0	82.6
Recurring Basis [Member] | Level 2 [Member] | Interest Rate Management Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	234.9	179.9
Derivative liabilities	15.1	12.7
Recurring Basis [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Recurring Basis [Member] | Level 3 [Member] | Forward Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Recurring Basis [Member] | Level 3 [Member] | Interest Rate Management Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	$ 0.0	$ 0.0