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Stock-based Compensatin (Stock Options) (Details) - CAD
CAD / shares in Units, CAD in Millions

12 Months Ended

Dec. 31, 2016

Dec. 31, 2015

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period

620,000

80,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period

620,000

80,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value

CAD 2.8

CAD 2.66

Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options

CAD 3

CAD 3

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition

2 years 4 months 24 days

2 years 3 months 18 days

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term

5 years 8 months 21 days

5 years 3 months 18 days

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value

CAD 21

CAD 17

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value

CAD 2

CAD 1

Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Beginning Balance

2,927,068

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

615,100

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period

(622,168)

Ending Balance

2,920,000

2,927,068

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number

^[1],[2]

1,399,875

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]

Beginning Balance

CAD 33.07

Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price

46.19

Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price

25.65

Ending Balance

37.42

CAD 33.07

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price

^[1],[2]

CAD 33.35

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

615,100

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period

(622,168)

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]

Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price

CAD 25.65

Employee Non-vested Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

^[3]

615,100

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares

^[3]

0

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]

Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price

CAD 2.8

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]

Beginning Balance

^[3]

1,453,486

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

^[3]

615,100

Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Options Forfeited Number Of Shares

^[3]

(548,461)

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares

^[3]

0

Ending Balance

^[3]

1,520,125

1,453,486

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]

Beginning Balance

CAD 2.64

Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price

2.8

Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Options Forfeited Weighted Average Grant Date Fair Value

2.68

Ending Balance

CAD 2.69

CAD 2.64

Stock Option Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition

2 years 3 months 18 days

2 years 6 months

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term

2 years 3 months 18 days

5 years 6 months

[1]	As at December 31, 2016 the fair value of options that vested in the year was $2 million (2015 - $1 million).
[2]	As at December 31, 2016, the weighted average remaining term of vested options was 5.7 years with an aggregate intrinsic value of $17 million (2015 - 5.3 years, $21 million).
[3]	As at December 31, 2016 there was $3 million of unrecognized compensation related to stock options not yet vested which is expected to be recognized over a weighted average period of approximately 2.4 years (2015 - $3 million, 2.3 years).

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+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
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