Debt

A summary of short-term and long-term debt outstanding is as follows:



(in millions)	December 31,
	2014		2013
5.9% Senior Notes, due 2017 ¹	$	400	$	400
6.55% Senior Notes, due 2037 ²	399		399
Commercial paper	—		—
Total debt	799		799
Less: short-term debt including current maturities	—		—
Long-term debt	$	799	$	799


¹	Interest payments are due semiannually on April 15 and October 15, and as of December 31, 2014, the unamortized debt discount is less than $1 million.


²	Interest payments are due semiannually on May 15 and November 15, and as of December 31, 2014, the unamortized debt discount is approximately $1 million.

Annual long-term debt maturities are scheduled as follows based on book values as of December 31, 2014: no amounts due from 2015 – 2016, approximately $400 million due in 2017 and approximately $399 million due thereafter.

Currently, we have the ability to borrow a total of $1.0 billion through our commercial paper program, which is supported by our $1.0 billion four-year credit agreement (our "credit facility") that we entered into in June 2013 and will terminate on June 19, 2017. As of December 31, 2014 and 2013, we had no outstanding commercial paper.

We pay a commitment fee of 20 to 45 basis points for our credit facility, depending on our indebtedness to cash flow ratio, whether or not amounts have been borrowed and currently pay a commitment fee of 20 basis points. The interest rate on borrowings under our credit facility is, at our option, calculated using rates that are primarily based on either the prevailing London Inter-Bank Offer Rate, the prime rate determined by the administrative agent or the Federal Funds Rate. For certain borrowings under this credit facility there is also a spread based on our indebtedness to cash flow ratio added to the applicable rate.

Our credit facility contains certain covenants. The only financial covenant requires that our indebtedness to cash flow ratio, as defined in our credit facility, is not greater than 3.25 to 1, and this covenant has never been exceeded.