Long-term and Short-term Debt

Long-term debt consists of (in millions):



	September 30,
	2018			2017
5.65% notes, repaid in December 2017	$	—		$	250.0
2.050% notes, payable in March 2020	294.6			298.7
2.875% notes, payable in March 2025	281.4			296.7
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	(50.8		)	(52.0		)
Total	1,225.2			1,493.4
Less current portion	—			(250.0		)
Long-term debt	$	1,225.2		$	1,243.4

In February 2015, upon issuance of our notes payable in March 2020 (2020 Notes) and March 2025 (2025 Notes), we entered into fixed-to-floating interest rate swap contracts with multiple banks that effectively converted the $600.0 million aggregate principal amount to floating rate debt, each at a rate based on three-month LIBOR plus a fixed spread. The effective floating interest rates were 2.759 percent for the 2020 Notes and 3.169 percent for the 2025 Notes at September 30, 2018. The aggregate fair value of the interest rate swap contracts at September 30, 2018 was a net unrealized loss of $24.0 million. We have designated these swaps as fair value hedges. The individual contracts are recorded in Other liabilities in 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 9.

At September 30, 2018 and 2017, our total borrowing capacity under our unsecured revolving credit facility expiring in March 2020 was $1.0 billion. 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 this credit facility during the years ended September 30, 2018 or 2017. Borrowings under this credit facility bear interest based on short-term money market rates in effect during the period the borrowings are outstanding. In December 2016, we amended the financial covenant under this credit facility. The previous financial covenant, which limited our debt-to-total-capital ratio to 60 percent, was replaced with a minimum EBITDA-to-interest ratio of 3.0 to 1.0. The EBITDA-to-interest ratio is defined in the amendment as the ratio of consolidated EBITDA (as defined in the amendment) for the preceding four quarters to consolidated interest expense for the same period. We believe the new covenant provides us greater financial flexibility. Separate short-term unsecured credit facilities of approximately $156.0 million at September 30, 2018 were available to non-U.S. subsidiaries. Borrowings under our non-U.S. credit facilities at September 30, 2018 and 2017 were not significant. There are no significant commitment fees or compensating balance requirements under any of our credit facilities.

Our short-term debt obligations are primarily comprised of commercial paper borrowings. Commercial paper borrowings outstanding were $550.0 million at September 30, 2018 and $350.0 million at September 30, 2017. The weighted average interest rate of the commercial paper outstanding was 2.27 percent at September 30, 2018 and 1.26 percent at September 30, 2017.

Interest payments were $75.5 million during 2018, $74.2 million during 2017 and $69.2 million during 2016.

Long-term debt is not measured at fair value. The following table presents the carrying amounts and estimated fair values of long-term debt not measured at fair value in the Consolidated Balance Sheet (in millions):



	September 30, 2018				September 30, 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Current portion of long-term debt	$	—	$	—	$	250.0	$	251.6
Long-term debt	1,225.2		1,391.3		1,243.4		1,452.6

We base the fair value of long-term debt upon quoted market prices for the same or similar issues and therefore consider this a Level 2 fair value measurement. The fair value of long-term debt considers the terms of the debt excluding the impact of derivative and hedging activity. The carrying amount of a portion of our long-term debt is impacted by fixed-to-floating interest rate swap contracts that are designated as fair value hedges. Refer to Note 1 for further information regarding levels in the fair value hierarchy.