Cash Flow Disclosures (Tables)

9 Months Ended

Sep. 30, 2015

Cash Flow Disclosures [Abstract]

Cash Flow Activities

	Nine Months
		Ended September 30,
(Thousands of dollars)	2015		2014
Net decrease in operating working capital other than    cash and cash equivalents:
Decrease in accounts receivable	$	389,413	29,586
Increase in inventories		(16,607)	(3,326)
Increase in prepaid expenses		(87,051)	(2,235)
Decrease in deferred income tax assets		4,863	1,290
Increase (decrease) in accounts payable and accrued liabilities		(134,458)	59,369
Decrease in current income tax liabilities		(59,134)	(77,744)
Total	$	97,026	6,940
Supplementary disclosures (including discontinued operations):
Cash income taxes paid, net of refunds	$	111,897	438,309
Interest paid, net of amounts capitalized		60,766	44,657
Non-cash investing activities, related to continuing operations:
Asset retirement costs capitalized	$	55,258	15,509
Decrease in capital expenditure accrual		374,720	106,031