Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2014

Property, Plant And Equipment [Abstract]

Property, Plant and Equipment

	December 31, 2014				December 31, 2013
(Thousands of dollars)	Cost		Net		Cost	Net
Exploration and production1	$	22,731,220	13,277,985	2	21,932,119	13,433,468	2
Corporate and other		103,351	53,062		89,175	47,587
	$	22,834,571	13,331,047		22,021,294	13,481,055
1  Includes mineral rights as follows:	$	924,253	410,482		1,007,920	489,578
2  Includes $58,334 in 2014 and $48,691     in 2013 related to administrative assets     and support equipment.

Net Changes in Capitalized Exploratory Well Costs

(Thousands of dollars)		2014	2013	2012
Beginning balance at January 1	$	393,030	445,697	556,412
Additions to capitalized exploratory well costs pending the      determination of proved reserves		2,874	57,716	135,849
Reclassifications to proved properties based on the      determination of proved reserves		(91,236)	(93,936)	(165,377)
Reduction of capitalized exploratory well costs due to      partial asset sale in Malaysia		(122,175)	–	–
Capitalized exploratory well costs charged to expense		(62,038)	(16,447)	(81,187)
Ending balance at December 31	$	120,455	393,030	445,697

Aging of Capitalized Exploratory Well Costs

	2014				2013				2012
(Thousands of dollars)	Amount		No. of Wells	No. of Projects	Amount		No. of Wells	No. of Projects	Amount		No. of Wells	No. of Projects
Aging of capitalized    well costs:
Zero to one year	$	–	–	–	$	56,499	3	1	$	59,833	7	2
One to two years		59,330	3	1		60,787	7	1		18,335	2	3
Two to three years		6,606	3	–		–	–	–		83,314	9	4
Three years or more		54,519	2	2		275,744	22	7		284,215	26	6
	$	120,455	8	3	$	393,030	32	9	$	445,697	44	15