Financial Instruments (Schedule of Outstanding Currency Price Risk Management Instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012
Derivative [Line Items]
US$ Notional	2,486.0	2,605.7
Forward Exchange Contracts [Member]
Derivative [Line Items]
Years Average Maturity	1 year 0 months	1 year 0 months
Forward Exchange Contracts [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
US$ Notional	1,306.4	1,348.8
Years Average Maturity	0 years 7 months	0 years 7 months
Forward Exchange Contracts [Member] | Net Investment Hedges [Member]
Derivative [Line Items]
US$ Notional	797.0	779.2
Years Average Maturity	2 years 2 months	2 years 6 months
Forward Exchange Contracts [Member] | Hedges Not Designated [Member]
Derivative [Line Items]
US$ Notional	382.6	477.7
Years Average Maturity	0 years 1 month	0 years 1 month