Contingencies - Additional Information (Detail) (CAD) In Billions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Amount related to damages	3.5
KS Centoco Ltd [Member]
Number of subsidiaries sued by KS Centoco Ltd	2
Percentage of equity interest owned by company	23.00%
Percentage of equity interest owned by third party	77.00%
MST Automotive Inc [Member]
Percentage of equity interest owned by company	77.00%
Percentage of equity interest owned by third party	23.00%

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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