Financial Instruments and Risk Management (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments and Hedging Activities Disclosure [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:

	December 31, 2016								December 31, 2015
Millions of dollars	Level 1		Level 2		Total fair value		Carrying value		Level 1		Level 2		Total fair value		Carrying value
Long-term debt	$	753	$	12,812	$	13,565	$	12,377	$	1,009	$	14,947	$	15,956	$	15,346