Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of the Major Components of the Company's Income Tax Expense

The following is a summary of the major components of the Company’s income tax expense:

(in millions of Canadian dollars)	2017			2016			2015
Current income tax expense	$	303		$	233		$	373
Deferred income tax expense
Origination and reversal of temporary differences	371			336			105
Effect of tax rate (decrease) increase	(541		)	—			23
Effect of hedge of net investment in foreign subsidiaries	(42		)	(20		)	100
Other	2			4			6
Total deferred income tax (recovery) expense	(210		)	320			234
Total income taxes	$	93		$	553		$	607
Income before income tax expense
Canada	$	1,829		$	1,513		$	1,099
Foreign	669			639			860
Total income before income tax expense	$	2,498		$	2,152		$	1,959
Income tax expense
Current
Canada	$	257		$	165		$	173
Foreign	46			68			200
Total current income tax expense	303			233			373
Deferred
Canada	256			207			163
Foreign	(466		)	113			71
Total deferred income tax (recovery) expense	(210		)	320			234
Total income taxes	$	93		$	553		$	607

Components of Deferred Income Tax Assets and Liabilities

The items comprising the deferred income tax assets and liabilities are as follows:

(in millions of Canadian dollars)	2017		2016
Deferred income tax assets
Amount related to tax losses carried forward	$	12	$	18
Liabilities carrying value in excess of tax basis	88		149
Environmental remediation costs	16		30
Other	11		58
Total deferred income tax assets	127		255
Deferred income tax liabilities
Properties carrying value in excess of tax basis	3,181		3,796
Pensions carrying value in excess of tax basis(1)	226		—
Other	41		30
Total deferred income tax liabilities	3,448		3,826
Total net deferred income tax liabilities	$	3,321	$	3,571

⁽¹⁾ Balance previously included as part of "Liabilities carrying value in excess of tax basis" as a component of deferred income tax assets.

Expected Income Tax Expense Reconciled To Income Tax Expense

Expected income tax expense at statutory rates is reconciled to income tax expense as follows:

(in millions of Canadian dollars, except percentage)	2017			2016			2015
Statutory federal and provincial income tax rate (Canada)	26.56		%	26.65		%	26.47		%
Expected income tax expense at Canadian enacted statutory tax rates	$	663		$	573		$	519
Increase (decrease) in taxes resulting from:
(Gains) losses not subject to tax	(27		)	(23		)	28
Canadian tax rate differentials	1			—			1
Foreign tax rate differentials	(9		)	—			39
Effect of tax rate (decrease) increase	(541		)	—			23
Other	6			3			(3		)
Income tax expense	$	93		$	553		$	607

Reconciliation of Uncertain Tax Positions In Relation To Unrecognized Tax Benefits for Canada and the United States

The following table provides a reconciliation of uncertain tax positions in relation to unrecognized tax benefits for Canada and the U.S. for the year ended December 31, 2017:

(in millions of Canadian dollars)	2017		2016			2015
Unrecognized tax benefits at January 1	$	13	$	15		$	17
Increase in unrecognized:
Tax benefits related to the current year	—		—			4
Dispositions:
Gross uncertain tax benefits related to prior years	—		(2		)	(6		)
Unrecognized tax benefits at December 31	$	13	$	13		$	15