Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

	Goodwill			Intangible assets
(in millions of Canadian dollars)	Net carrying amount			Cost		Accumulated amortization			Net carrying amount			Total goodwill and intangible assets
Balance at December 31, 2015	$	198		$	22	$	(9	)	$	13		$	211
Amortization	—			—		(1		)	(1		)	(1		)
Foreign exchange impact	(7		)	—		(1		)	(1		)	(8		)
Balance at December 31, 2016	$	191		$	22	$	(11	)	$	11		$	202
Amortization	—			—		(1		)	(1		)	(1		)
Foreign exchange impact	(13		)	—		(1		)	(1		)	(14		)
Balance at December 31, 2017	$	178		$	22	$	(13	)	$	9		$	187