Debt

Our total debt, including short-term borrowings and current maturities of long-term debt, consisted of the following:



	December 31
Millions of dollars	2017			2016
5.0% senior notes due November 2045	$	2,000		$	2,000
3.8% senior notes due November 2025	2,000			2,000
3.5% senior notes due August 2023	1,100			1,100
4.85% senior notes due November 2035	1,000			1,000
7.45% senior notes due September 2039	1,000			1,000
4.75% senior notes due August 2043	900			900
6.7% senior notes due September 2038	800			800
3.25% senior notes due November 2021	500			500
4.5% senior notes due November 2041	500			500
2.0% senior notes due August 2018	400			400
7.6% senior debentures due August 2096	300			300
8.75% senior debentures due February 2021	185			185
6.75% notes due February 2027	104			104
6.15% senior notes due September 2019	—			1,000
5.9% senior notes due September 2018	—			400
7.53% notes due May 2017	—			45
Other	251			260
Unamortized debt issuance costs and discounts	(98		)	(110		)
Total	10,942			12,384
Short-term borrowings and current maturities of long-term debt	(512		)	(170		)
Total long-term debt	$	10,430		$	12,214

Senior debt

All of our senior notes and debentures rank equally with our existing and future senior unsecured indebtedness, have semiannual interest payments and have no sinking fund requirements. We may redeem all of our senior notes from time to time or all of the notes of each series at any time at the applicable redemption prices, plus accrued and unpaid interest. Our 7.60% and 8.75% senior debentures may not be redeemed prior to maturity.

In March 2017, we used cash on hand to redeem an aggregate principal amount of $1.4 billion of senior notes, which consisted of $400 million of 5.9% senior notes due September 2018 and $1.0 billion of 6.15% senior notes due September 2019. In conjunction with this redemption, we terminated a series of interest rate swaps associated with these senior notes. As a result, we recorded $104 million in costs related to the early extinguishment of debt, which included the redemption premium and a write-off of the remaining original debt issuance costs and debt discount, partially offset by a gain from the termination of the related interest rate swap agreements. These debt extinguishment costs are included in interest expense on our consolidated statement of operations for the year ended December 31, 2017. We also repaid $45 million of notes that matured in May 2017. Our $400 million of 2.0% senior notes will mature in August 2018, which we intend to repay with cash on hand.

Revolving credit facilities

We have a revolving credit facility with a capacity of $3.0 billion which expires in July 2020. The facility is for working capital or general corporate purposes. The full amount of the revolving credit facility was available as of December 31, 2017.

Debt maturities

Our long-term debt matures as follows: $440 million in 2018, $30 million in 2019, $26 million in 2020, $709 million in 2021, $14 million in 2022 and the remainder in 2023 and thereafter.