Income and other taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income tax expense:



For the years ended December 31	2017			2016
Current tax recovery (expense):
Current period before undernoted items	$	(85,287	)	$	(44,743	)
Impact of Argentina gas settlement	—			(7,800		)
Adjustments to prior years	(217		)	(2,134		)
	(85,504		)	(54,677		)
Deferred tax recovery (expense):
Origination and reversal of temporary differences	23,310			82,838
Impact of Argentina gas settlement	—			(3,575		)
Derecognition of non-capital loss carryforwards	—			(17,861		)
Adjustments to prior years	200			1,667
Change in U.S. tax rate	(36,567		)	—
Change in other jurisdictions tax rates	734			—
Other	2,039			887
	(10,284		)	63,956
Total income tax recovery (expense)	$	(95,788	)	$	9,279

Reconciliation of accounting profit multiplied by applicable tax rates

Income tax expense differs from the amounts that would be obtained by applying the Canadian statutory income tax rate to net income (loss) before income taxes as follows:



For the years ended December 31	2017			2016
Income (loss) before income taxes	$	470,885		$	(37,504	)
Deduct earnings of associate	(75,995		)	(19,930		)
	394,890			(57,434		)
Canadian statutory tax rate	26.5		%	26.5		%
Income tax recovery (expense) calculated at Canadian statutory tax rate	(104,646		)	15,220
Increase (decrease) in income tax recovery resulting from:
Impact of income and losses taxed in foreign jurisdictions	30,223			34,857
Derecognition of non-capital loss carryforwards	—			(17,861		)
Unrecognised loss carryforwards and temporary differences	20,468			(6,468		)
Impact of tax rate changes in the U.S.	(36,567		)	—
Impact of tax rate changes in other jurisdictions	734			—
Impact of foreign exchange	3,104			(4,332		)
Other business taxes	(4,105		)	(5,404		)
Adjustments to prior years	(17		)	(467		)
Other	(4,982		)	(6,266		)
Total income tax recovery (expense)	$	(95,788	)	$	9,279

Effect of temporary difference, unused tax losses and unused tax credits and analysis of change in deferred income tax liabilities

The tax effect of temporary differences that give rise to deferred income tax liabilities and deferred income tax assets are as follows:



As at				Dec 31 2017									Dec 31 2016
	Net			Deferred tax assets			Deferred tax liabilities			Net			Deferred tax assets			Deferred tax liabilities
Property, plant and equipment	$	(403,705	)	$	(189,368	)	$	(214,337	)	$	(419,982	)	$	(197,931	)	$	(222,051	)
Repatriation taxes	(87,239		)	—			(87,239		)	(85,364		)	—			(85,364		)
Other	(11,670		)	(3,740		)	(7,930		)	(19,956		)	(4,981		)	(14,975		)
	(502,614		)	(193,108		)	(309,506		)	(525,302		)	(202,912		)	(322,390		)
Non-capital loss carryforwards	244,576			244,576			—			280,931			280,931			—
Share-based compensation	19,920			2,946			16,974			8,590			935			7,655
Other	74,027			47,927			26,100			82,142			58,387			23,755
	338,523			295,449			43,074			371,663			340,253			31,410
Net deferred income tax assets (liabilities)	$	(164,091	)	$	102,341		$	(266,432	)	$	(153,639	)	$	137,341		$	(290,980	)

Analysis of the change in deferred income tax assets and liabilities:



							2017									2016
	Net			Deferred tax assets			Deferred tax liabilities			Net			Deferred tax assets			Deferred tax liabilities
Balance, January 1	$	(153,639	)	$	137,341		$	(290,980	)	$	(223,757	)	$	61,881		$	(285,638	)
Deferred income tax recovery (expense) included in net income (loss)	(10,284		)	(34,517		)	24,233			63,956			69,110			(5,154		)
Impact of U.S. tax rate change in other comprehensive income	(8,621		)	(8,621		)	—			—			—			—
Deferred income tax recovery (expense) included in other comprehensive income (loss)	9,295			8,398			897			6,597			6,364			233
Other	(842		)	(260		)	(582		)	(435		)	(14		)	(421		)
Balance, December 31	$	(164,091	)	$	102,341		$	(266,432	)	$	(153,639	)	$	137,341		$	(290,980	)