Fair Value of Financial Instruments Fair value by balance sheet grouping table (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

The carrying amount and fair value of our long-term debt, including current maturities, is as follows:

	September 30, 2015								December 31, 2014
Millions of dollars	Level 1		Level 2		Total fair value		Carrying value		Level 1		Level 2		Total fair value		Carrying value
Long-term debt	$	1,008	$	7,615	$	8,623	$	7,891	$	4,822	$	4,257	$	9,079	$	7,840