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

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

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

	March 31, 2018								December 31, 2017
Millions of dollars	Level 1		Level 2		Total fair value		Carrying value		Level 1		Level 2		Total fair value		Carrying value
Total debt	$	9,862	$	2,146	$	12,008	$	10,894	$	3,285	$	9,172	$	12,457	$	10,942