Debt

Long-term debt consisted of the following at both December 31, 2012 and 2011:



Millions of dollars
6.15% senior notes due September 2019	$	997
7.45% senior notes due September 2039	995
6.7% senior notes due September 2038	800
3.25% senior notes due November 2021	498
4.5% senior notes due November 2041	498
5.9% senior notes due September 2018	400
7.6% senior debentures due August 2096	293
8.75% senior debentures due February 2021	184
Other	155
Total long-term debt	$	4,820

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 $2.0 billion five-year revolving credit facility expiring in 2016. 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, 2012.

Debt maturities

$45 million of our long-term debt is due in 2017. The remainder is due in 2018 and thereafter.