Debt



(in millions)	March 31, 2016		December 31, 2015
5.9% Senior Notes, due 2017¹	$	400	399
2.5% Senior Notes, due 2018 ²	398		398
3.3% Senior Notes, due 2020 ³	695		695
4.0% Senior Notes, due 2025 ⁴	690		690
4.4% Senior Notes, due 2026 ⁵	890		890
6.55% Senior Notes, due 2037 ⁶	396		396
Commercial paper	322		143
Revolving line of credit	150		—
Total debt	3,941		3,611
Less: short-term debt including current maturities	472		143
Long-term debt	$	3,469	$	3,468


¹	Interest payments are due semiannually on April 15 and October 15, and as of March 31, 2016, the unamortized debt discount and issuance costs are less than $1 million.


²	Interest payments are due semiannually on February 15 and August 15, and as of March 31, 2016, the unamortized debt discount and issuance costs total $2 million.


³	Interest payments are due semiannually on February 14 and August 14, and as of March 31, 2016, the unamortized debt discount and issuance costs total $5 million.


⁴	Interest payments are due semiannually on June 15 and December 15, and as of March 31, 2016, the unamortized debt discount and issuance costs total $10 million.


⁵	Interest payments are due semiannually on February 15 and August 15, and as of March 31, 2016, the unamortized debt discount and issuance costs total $10 million.


⁶	Interest payments are due semiannually on May 15 and November 15, and as of March 31, 2016, the unamortized debt discount and issuance costs total $4 million.

The fair value of our long-term debt borrowings was $3.7 billion and $3.6 billion as of March 31, 2016 and December 31, 2015, respectively, and was estimated based on quoted market prices.

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, 2015. This credit facility will terminate on June 30, 2020. Commercial paper borrowings outstanding as of March 31, 2016 and December 31, 2015 totaled $322 million and $143 million, respectively with an average interest rate and term of 0.91% and 24 days and 0.95% and 17 days, respectively. Our revolving line of credit outstanding as of March 31, 2016 totaled $150 million with an interest rate of 1.68% and residual term of 25 days. There were no amounts outstanding on the revolving line of credit as of December 31, 2015. As of March 31, 2016, we can borrow approximately $728 million in additional funds under our credit facility.

We pay a commitment fee of 10 to 20 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 15 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 4 to 1, and this covenant level has never been exceeded.