Debt

3 Months Ended

Mar. 31, 2021

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


(in millions)	March 31, 2021	December 31, 2020
4.0% Senior Notes, due 2025 1	695	695
2.95% Senior Notes, due 2027 2	495	495
2.5% Senior Notes, due 2029 3	496	495
1.25% Senior Notes, due 2030 4	592	592
6.55% Senior Notes, due 2037 5	290	290
4.5% Senior Notes, due 2048 6	273	273
3.25% Senior Notes, due 2049 7	589	589
2.3% Senior Notes, due 2060 8	681	681




Long-term debt	4,111	4,110

1Interest payments are due semiannually on June 15 and December 15, and as of March 31, 2021, the unamortized debt discount and issuance costs total $5 million.

2Interest payments are due semiannually on January 22 and July 22, and as of March 31, 2021, the unamortized debt discount and issuance costs total $5 million.

3Interest payments are due semiannually on June 1 and December 1, and as of March 31, 2021, the unamortized debt discount and issuance costs total $4 million.

4Interest payments are due semiannually on February 15 and August 15, beginning on February 15, 2021, and as of March 31, 2021, the unamortized debt discount and issuance costs total $8 million.

5Interest payments are due semiannually on May 15 and November 15, and as of March 31, 2021, the unamortized debt discount and issuance costs total $3 million.

6Interest payments are due semiannually on May 15 and November 15, and as of March 31, 2021, the unamortized debt discount and issuance costs total $10 million.

7Interest payments are due semiannually on June 1 and December 1, and as of March 31, 2021, the unamortized debt discount and issuance costs total $11 million.

8Interest payments are due semiannually on February 15 and August 15, beginning on February 15, 2021, and as of March 31, 2021, the unamortized debt discount and issuance costs total $19 million.

The fair value of our total debt borrowings was $4.3 billion and $4.6 billion as of March 31, 2021 and December 31, 2020, respectively, and was estimated based on quoted market prices.

On April 26, 2021, we entered into a revolving $1.5 billion five-year credit agreement (our "credit facility") that will terminate on April 26, 2026. This credit facility replaced our revolving $1.2 billion five-year credit facility (our "previous credit facility") that was scheduled to terminate on June 30, 2022. The previous credit facility was canceled immediately after the new credit facility became effective. There were no outstanding borrowings under the previous credit facility when it was replaced.

As of March 31, 2021 and December 31, 2020, we had the ability to borrow a total of $1.2 billion through our commercial paper program, which was supported by our previous credit facility that we entered into on June 30, 2017. As of March 31, 2021 and December 31, 2020, there was no commercial paper issued or outstanding, and we similarly did not draw or have any borrowings outstanding from the previous credit facility during the three months ended March 31, 2021 and 2020.

Depending on our corporate credit rating, we paid a commitment fee of 8 to 17.5 basis points for our previous credit facility, whether or not amounts have been borrowed. During the three months ended March 31, 2021, we paid a commitment fee of 10 basis points. The interest rate on borrowings under our previous credit facility was, 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 previous credit facility, there was also a spread based on our corporate credit rating.

Our previous credit facility contained certain covenants. The only financial covenant required that our indebtedness to cash flow ratio, as defined in our previous credit facility, was not greater than 4 to 1, and this covenant level has never been exceeded.