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Employee Benefit Plans (Amounts to be Amortized in the Next Fiscal Year) (Details) CAD in Millions	12 Months Ended
	Dec. 31, 2016 CAD
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Future Amortization of Gain (Loss)	CAD (53)
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	1
Regulated assets	(16)
Total	(68)
Non-pension Benefit Plans [Member
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Future Amortization of Gain (Loss)	(1)
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	8
Regulated assets	3
Total	CAD 10

X

- Definition

Amount included in accumulated other comprehensive income (AOCI) related to Regulated assets expected to be recognized as components of net periodic benefit cost (credit) for the fiscal year that follows the most recent annual statement of financial position.

+ References

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- Definition

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount included in accumulated other comprehensive income (AOCI) related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

+ References

No definition available.

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Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

+ References

No definition available.

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