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

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Available-for-sale Securities

At March 31, 2015, we held $105 million of investments in fixed income securities with maturities ranging from less than one year to November 2019, of which $61 million are classified as “Other current assets” and $44 million are classified as “Other assets” on our condensed consolidated balance sheets. At December 31, 2014, we held $103 million of investments in fixed income securities, of which $56 million are classified as “Other current assets” and $47 million are classified as “Other assets” on our condensed consolidated balance sheets.

These securities consist primarily of corporate bonds and other debt instruments, are accounted for as available-for-sale and recorded at fair value, and are classified as Level 2 assets.

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

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

	March 31, 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	$	5,511	$	3,753	$	9,264	$	7,841	$	4,822	$	4,257	$	9,079	$	7,840