Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of long-term debt

Our long-term debt, including current maturities, consisted of the following:

	December 31
Millions of dollars	2016			2015
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
6.15% senior notes due September 2019	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
5.9% senior notes due September 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
7.53% notes due May 2017	45			45
3.375% senior notes due November 2022	—			1,250
2.7% senior notes due November 2020	—			1,250
1.0% senior notes due August 2016	—			600
Other	253			144
Unamortized debt issuance costs and discounts	(110		)	(132		)
Total	12,377			15,346
Current maturities	(163		)	(659		)
Total long-term debt	$	12,214		$	14,687