Gain on Sale of Properties - Gain on Settlement of Legal Proceedings Related to the Purchase and Sale of a Building (Details) - CAD CAD in Millions	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Amount of interest free loan		CAD 20
Carrying value of purchase option		CAD 8
Proceeds from sale of building	CAD 59
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	31
Gain on sale of building, after tax	CAD 27

Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721525-107759

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Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

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The carrying amount as of the balance sheet date of land not owned but under a contract in which the entity has an option to purchase the land.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The face amount of loans that will be sold to other entities.

+ References

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- Definition

The cash inflow from sale of buildings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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