Debt

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



(in millions)	December 31,
	2018		2017
2.5% Senior Notes, due 2018 ¹	$	—	$	399
3.3% Senior Notes, due 2020 ²	698		697
4.0% Senior Notes, due 2025 ³	693		692
4.4% Senior Notes, due 2026 ⁴	892		892
2.95% Senior Notes, due 2027 ⁵	493		493
6.55% Senior Notes, due 2037 ⁶	396		396
4.5% Senior Notes, due 2048 ⁷	490		—
Total debt	3,662		3,569
Less: short-term debt including current maturities	—		399
Long-term debt	$	3,662	$	3,170


¹	We made a $400 million early repayment of our 2.5% senior note in June of 2018.


²	Interest payments are due semiannually on February 14 and August 14, and as of December 31, 2018, the unamortized debt discount and issuance costs total $2 million.


³	Interest payments are due semiannually on June 15 and December 15, and as of December 31, 2018, the unamortized debt discount and issuance costs total $7 million.


⁴	Interest payments are due semiannually on February 15 and August 15, and as of December 31, 2018, the unamortized debt discount and issuance costs total $8 million.


⁵	Interest payments are due semiannually on January 22 and July 22, and as of December 31, 2018, the unamortized debt discount and issuance costs total $7 million.


⁶	Interest payments are due semiannually on May 15 and November 15, and as of December 31, 2018, the unamortized debt discount and issuance costs total $4 million.


⁷	Interest payments are due semiannually on May 15 and November 15, and as of December 31, 2018, the unamortized debt discount and issuance costs total $10 million.

Annual debt maturities are scheduled as follows based on book values as of December 31, 2018: no amounts due in 2019, $698 million due in 2020, no amounts due in 2021, 2022, and 2023 and $3.0 billion due thereafter.

On May 17, 2018, we issued $500 million of 4.5% notes due in 2048. The notes are fully and unconditionally guaranteed by our wholly-owned subsidiary, Standard & Poor's Financial Services LLC. In June of 2018, we used the net proceeds to fund the redemption price of the $400 million outstanding principal amount of our 2.5% senior notes due in August of 2018, and the balance for general corporate purposes.

On September 22, 2016, we issued $500 million of 2.95% senior notes due in 2027. The notes are fully and unconditionally guaranteed by our wholly-owned subsidiary, Standard & Poor's Financial Services LLC. We used the net proceeds to fund the $400 million early repayment of our 5.9% senior notes due in 2017 on October 20, 2016, and the balance for general corporate purposes.

We have the ability to borrow a total of $1.2 billion through our commercial paper program, which is supported by our revolving $1.2 billion five-year credit agreement (our "credit facility") that we entered into on June 30, 2017. This credit facility will terminate on June 30, 2022. There were no commercial paper borrowings outstanding as of December 31, 2018 and 2017.

Depending on our corporate credit rating, we pay a commitment fee of 8 to 17.5 basis points for our credit facility, whether or not amounts have been borrowed. We currently pay a commitment fee of 10 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 corporate credit rating.

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 4 to 1, and this covenant level has never been exceeded.