Income taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income taxes

Schedule of components of earnings before income taxes

	Year ended December 31,
	2018		2017		2016
Canadian	$	(97)	$	25	$	60
Non-Canadian		(1,231)		(129)		7
(Loss) income before taxes	$	(1,328)	$	(104)	$	67

Schedule of Income tax expense / (benefit)

	Year ended December 31,
	2018		2017		2016
Current tax (benefit) expense:
Canadian	$	(5)	$	1	$	2
Non-Canadian		—		1		—
Total	$	(5)	$	2	$	2
Deferred tax benefit:
Canadian		(54)		(22)		(3)
Non-Canadian		(3)		(142)		—
Total		(57)		(164)		(3)
Income tax benefit	$	(62)	$	(162)	$	(1)

Schedule of reconciliation of the US statutory income tax rate to our effective income tax rate

	Year ended December 31,
	2018			2017			2016
Statutory Federal and Provincial tax rate in Canada		27	%		26	%		26	%
Expected income tax expense (benefit) at statutory rate	$	(358)		$	(27)		$	17
Impact of Tax Cuts and Jobs Act of 2017		—			26			—
Change in statutory tax rates		23			(1)			—
Non-deductible expenses		1			10			2
Foreign exchange differences		(44)			(1)			1
Change in valuation allowance		207			(123)			13
Changes in uncertain tax positions		(20)			(14)			(4)
Foreign earnings subject to different tax rates		(27)			(13)			(10)
Research and development tax credits		(18)			(19)			(20)
Non-deductible goodwill impairment		172			—			—
Other		2			—			—
Income tax	$	(62)		$	(162)		$	(1)
Effective income tax rate		4.7	%		155.8	%		(1.5)	%

Schedule of significant components of deferred tax assets and liabilities

	Year ended December 31,
	2018		2017		2016
Tax benefit of losses carried forward	$	323	$	247	$	94
Research and development tax credits		175		121		45
Construction contract assets and liabilities		79		71		3
Property and equipment		15		5		—
Goodwill and intangibles		1		—		1
Trade and other payables		39		27		22
Employee benefits		55		58		85
Unrealized foreign exchange gains and losses		39		10		12
Other		2		—		1
Sub-total		728		539		263
Less: Valuation allowance		(366)		(157)		(200)
Deferred tax assets, net of valuation allowance	$	362	$	382	$	63
Construction contract assets and liabilities		(6)		(3)		(3)
Property and equipment		(3)		(1)		(12)
Goodwill and intangibles		(253)		(303)		—
Research and development tax credits		—		—		(6)
Unrealized foreign exchange gains and losses		—		(11)		(8)
Debt issuance costs		(3)		(3)		—
Other		—		(3)		—
Total net deferred tax liabilities		(265)		(324)		(29)
Deferred tax assets, net	$	97	$	58	$	34

Schedule of changes in unrecognized tax benefits

	Year ended December 31,
	2018		2017		2016
Balance, beginning of year	$	132	$	133	$	119
Gross increases related to prior period tax positions		9		5		7
Gross increases related to current period tax positions		13		6		10
Decrease related to resolution of audits with tax authorities		(28)		—		—
Expiration of the statute of limitations		(22)		(21)		(6)
Foreign currency translation		(10)		9		3
Balance, end of year	$	94	$	132	$	133