Debt (Tables)

12 Months Ended

Dec. 31, 2012

Debt Disclosure [Abstract]

Schedule of long-term 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