OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Operating Profit (Details) - CAD ($) $ in Millions	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Disclosure of operating segments [line items]
Segment operating income	$ 461.0	$ 364.7
Restructuring, integration and acquisition costs	0.0	(35.5)
Operating segments
Disclosure of operating segments [line items]
Segment operating income	$ 461.0	$ 400.2

The profit (loss) from operating activities of the entity. [Refer: Profit (loss)]

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