Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes [Abstract]

Components of Income (Loss) from Continuing Operations Before Income Taxes and Income Tax Expense

(Thousands of dollars)	2018		2017	2016
Income (loss) from continuing operations before income taxes
United States	$	14,907	(299,349)	(595,196)
Foreign		417,431	371,151	102,081
Total	$	432,338	71,802	(493,115)
Income tax expense (benefit)
Federal – Current	$	(9,765)	–	-
– Deferred		(131,200)	156,065	(197,450)
Total Federal		(140,965)	156,065	(197,450)
State		3,299	4,230	13,984
Foreign – Current		202,775	122,318	146,861
– Deferred		(55,779)	100,125	(182,567)
Total Foreign		146,996	222,443	(35,706)
Total	$	9,330	382,738	(219,172)

Effective Income Tax Rates

(Thousands of dollars)	2018		2017	2016
Income tax expense (benefit) based on the U.S. statutory tax rate	$	90,791	25,131	(172,590)
Revaluation of deferred tax (US tax reform)		–	118,004	–
Tax impact of deemed repatriation of foreign invested earnings (U.S. tax reform)		(135,700)	156,000	–
Deferred tax effect on Canadian earnings no longer indefinitely invested		–	65,000	–
Foreign income (loss) subject to foreign tax rates different than      the U.S. statutory rate		72,007	12,658	8,582
State income taxes, net of federal benefit		2,607	2,438	9,090
U.S. tax benefit on certain foreign upstream investments		(14,702)	(32,926)	(21,336)
Tax effects on sale of Canadian assets		–	–	(89,473)
Tax effects on sale of Malaysian assets		–	–	2,080
Increase in deferred tax asset valuation allowance related      to other foreign exploration expenditures		3,283	18,601	25,734
Other, net		(8,956)	17,832	18,741
Total	$	9,330	382,738	(219,172)

Analysis of Deferred Tax Assets and Deferred Tax Liabilities Showing Tax Effects of Significant Temporary Differences

(Thousands of dollars)	2018		2017
Deferred tax assets
Property and leasehold costs	$	491,660	488,584
Liabilities for dismantlements		88,075	98,444
Postretirement and other employee benefits		113,826	134,444
Alternative minimum tax		9,765	29,710
Foreign tax credit carryforwards		–	228,159
U. S. net operating loss		496,629	272,930
Other deferred tax assets		19,974	13,892
Total gross deferred tax assets		1,219,929	1,266,163
Less valuation allowance		(213,815)	(476,256)
Net deferred tax assets		1,006,114	789,907
Deferred tax liabilities
Deferred tax on undistributed foreign earnings		(5,000)	(65,000)
Accumulated depreciation, depletion and amortization		(742,562)	(669,638)
Other deferred tax liabilities		(28,802)	(2,824)
Total gross deferred tax liabilities		(776,364)	(737,462)
Net deferred tax assets	$	229,750	52,445

Reconciliation of Beginning and Ending Amount of Consolidated Liability for Unrecognized Income Tax Benefits

(Thousands of dollars)	2018		2017	2016
Balance at January 1	$	3,437	7,417	6,631
Additions for tax positions related to current year		454	769	756
Settlements due to lapse of time		(988)	(4,834)	–
Foreign currency translation effect		–	85	30
Balance at December 31	$	2,903	3,437	7,417