Debt

Long-term debt consisted of the following:



	December 31
Millions of dollars	2014			2013
3.5% senior notes due August 2023	$	1,098		$	1,098
6.15% senior notes due September 2019	998			997
7.45% senior notes due September 2039	995			995
4.75% senior notes due August 2043	898			898
6.7% senior notes due September 2038	800			800
1.0% senior notes due August 2016	600			600
3.25% senior notes due November 2021	499			498
4.5% senior notes due November 2041	498			498
2.0% senior notes due August 2018	400			400
5.9% senior notes due September 2018	400			400
7.6% senior debentures due August 2096	293			293
8.75% senior debentures due February 2021	184			184
6.75% notes due February 2027	104			104
7.53% notes due May 2017	45			45
Other	42			6
Total	$	7,854		$	7,816
Current maturities	(14		)	—
Total long-term debt	$	7,840		$	7,816

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 7.6% and 8.75% senior debentures may not be redeemed prior to maturity.

Revolving credit facilities

We have an unsecured $3.0 billion revolving credit facility expiring in 2018. The purpose of the facility is to provide general working capital and credit for other corporate purposes. The full amount of the revolving credit facility was available as of December 31, 2014.

Debt maturities

Our long-term debt matures as follows: $14 million in 2015, $610 million in 2016, $52 million in 2017, $806 million in 2018, $1.0 billion in 2019, and the remainder in 2020 and thereafter.

Bridge facility commitment

We have obtained a commitment letter for an $8.6 billion senior unsecured bridge facility expiring in November 2015, which may be automatically extended to April 30, 2016 if the termination date under the merger agreement is extended in accordance with the terms of the merger agreement. The amount of the bridge facility commitment is greater than the expected cash consideration to be paid upon the closing of the acquisition. We have not drawn any amounts under this commitment as of December 31, 2014. We may issue debt securities, obtain bank loans or other debt financings, or use cash on hand in lieu of utilizing all or a portion of the bridge facility. See Note 2 to the consolidated financial statements for further information about the pending acquisition.