Debt (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Schedule of long-term debt

	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