Debt

3 Months Ended

Mar. 31, 2020

Note 7—Debt



	Millions of Dollars
	March 31 2020			December 31 2019

2.450% Senior Notes due December 2024	$	300		300
3.605% Senior Notes due February 2025	500			500
3.550% Senior Notes due October 2026	500			500
3.750% Senior Notes due March 2028	500			500
3.150% Senior Notes due December 2029	600			600
4.680% Senior Notes due February 2045	450			450
4.900% Senior Notes due October 2046	625			625
Tax-exempt bonds due April 2020 and April 2021 at 1.465% and 1.85% at March 31, 2020, and December 31, 2019, respectively	75			75
Debt at face value	3,550			3,550
Net unamortized discounts and debt issuance costs	(34		)	(34	)
Total debt	3,516			3,516
Short-term debt	(25		)	(25	)
Long-term debt	$	3,491		3,491

The fair value of our fixed-rate and floating-rate debt is estimated based on observable market prices and is classified in level 2 of the fair value hierarchy. The fair value of our fixed-rate debt was $3,083 million and $3,650 million at March 31, 2020, and December 31, 2019, respectively. The fair value of our floating-rate debt approximated carrying value of $75 million at March 31, 2020, and December 31, 2019.

At March 31, 2020, and December 31, 2019, no amount had been directly drawn under our $750 million revolving credit facility; however, $3 million and $1 million in letters of credit had been issued under this facility at March 31, 2020, and December 31, 2019, respectively.

On April 1, 2020, we repaid at maturity a $25 million tranche of tax-exempt bonds that was included in short-term debt at March 31, 2020.