Long-term and Short-term Debt

Long-term debt consists of (in millions):



	September 30,
	2015			2014
5.65% notes, payable in December 2017	$	250.0		$	250.0
2.050% notes, payable in March 2020	304.2			—
2.875% notes, payable in March 2025	301.2			—
6.70% debentures, payable in January 2028	250.0			250.0
6.25% debentures, payable in December 2037	250.0			250.0
5.20% debentures, payable in January 2098	200.0			200.0
Unamortized discount and other	(54.5		)	(49.6		)
Long-term debt	$	1,500.9		$	900.4

In February 2015, we issued $600.0 million of aggregate principal amount of long-term notes in a public offering. The offering consisted of $300.0 million in 2.050% notes payable in March 2020 (2020 Notes) and $300.0 million in 2.875% notes payable in March 2025 (2025 Notes), both issued at a discount. This debt offering yielded $594.3 million in net proceeds. We used the net proceeds from the offering primarily to repay our outstanding commercial paper, with the remaining proceeds used for general corporate purposes.

Upon issuance of these notes, we entered into fixed-to-floating interest rate swap contracts with multiple banks that effectively converted the $600.0 million aggregate principal amount of our 2020 Notes and 2025 Notes to floating rate debt, each at a rate based on three-month LIBOR plus a fixed spread. The effective floating interest rates were 0.763 percent for the 2020 Notes and 1.173 percent for the 2025 Notes at September 30, 2015. We have designated these swaps as fair value hedges. The aggregate fair value of the interest rate swap contracts at September 30, 2015 was a net unrealized gain of $5.4 million. The individual contracts are recorded in other liabilities on the Consolidated Balance Sheet with corresponding adjustments to the carrying value of the underlying debt. Additional information related to our interest rate swap contracts is included in Note 8.

Our short-term debt obligations are primarily comprised of commercial paper borrowings. There were no commercial paper borrowings outstanding at September 30, 2015. Commercial paper borrowings outstanding were $325.0 million at September 30, 2014. The weighted average interest rate of the commercial paper outstanding was 0.17 percent at September 30, 2014.

On March 24, 2015, we replaced our former five-year $750.0 million unsecured revolving credit facility with a new five-year $1.0 billion unsecured revolving credit facility expiring in March 2020. We can increase the aggregate amount of this credit facility by up to $350.0 million, subject to the consent of the banks in the credit facility. We have not borrowed against either credit facility during the periods ended September 30, 2015 or September 30, 2014. Borrowings under this credit facility bear interest based on short-term money market rates in effect during the period the borrowings are outstanding. The terms of this credit facility contain covenants under which we would be in default if our debt-to-total-capital ratio was to exceed 60 percent. Separate short-term unsecured credit facilities of approximately $121.2 million at September 30, 2015 were available to non-U.S. subsidiaries. Borrowings under our non-U.S. credit facilities at September 30, 2015 and September 30, 2014 were not significant. There are no significant commitment fees or compensating balance requirements under any of our credit facilities.

Interest payments were $60.8 million during 2015, $58.1 million during 2014 and $59.7 million during 2013.