Other Financial Information (Tables)

12 Months Ended

Dec. 31, 2013

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Noncash Operating Working Capital (Increased) Decreased

Noncash operating working capital (increased) decreased during each of the three years ended December 31, 2013 as shown in the following table.

(Thousands of dollars)	2013			2012			2011
Accounts receivable	$	224,281			(382,137	)		90,608
Inventories		14,166			(94,907	)		(67,560	)
Prepaid expenses		195,013			(245,881	)		9,908
Deferred income tax assets		15,510			(7,218	)		15,914
Accounts payable and accrued liabilities		(176,543	)		534,353			(535,788	)
Current income tax liabilities		(6,098	)		27,610			(273,118	)
Net (increase) decrease in noncash operating working capital	$	266,329			(168,180	)		(760,036	)