Short-term Debt	6 Months Ended
Mar. 31, 2013
Debt Disclosure [Abstract]
Short-term Debt	Short-term Debt Our short-term debt obligations are comprised of commercial paper borrowings. Commercial paper borrowings outstanding were $236.0 million at March 31, 2013 and $157.0 million at September 30, 2012. At March 31, 2013, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.22 percent and nine days, respectively. At September 30, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and six days, respectively.

Short-term Debt

6 Months Ended

Mar. 31, 2013

Our short-term debt obligations are comprised of commercial paper borrowings. Commercial paper borrowings outstanding were $236.0 million at March 31, 2013 and $157.0 million at September 30, 2012. At March 31, 2013, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.22 percent and nine days, respectively. At September 30, 2012, the weighted average interest rate and maturity period of the commercial paper outstanding were 0.27 percent and six days, respectively.