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Other Income (Expenses), Net (Details) CAD in Millions, $ in Millions		3 Months Ended	12 Months Ended
	Jan. 25, 2015 CAD	Jun. 30, 2016 CAD	Dec. 31, 2016 CAD	Dec. 31, 2015 CAD	Jun. 30, 2016 USD ($)
Increase (Decrease) in Allowance for Equity Funds Used During Construction			CAD 22	CAD 2
Foreign Currency Transaction Gain (Loss), before Tax			(43)	27
Other			11	1
Other Nonoperating Income (Expense)			174	141
Algonquin Power and Utilities Corporation [Member]
Gain (Loss) on Investments			160	0
Gain Loss On Conversion Of Subscription Receipts			63	0
The Barbados Light and Power Company Limited [Member]
Gain (Loss) on Investments		CAD 53
Increase (Decrease) in Self Insurance Reserve			53	0
Self Insurance Reserve		30			$ 22
Gain (Loss) On Investments After Tax		CAD 43
TECO Energy Inc [Member]
Foreign Currency Transaction Gain (Loss), before Tax			(135)	119
Convertible Subordinated Debt				CAD 2,185
Convertible debenture interest rate				4.00%
Northeast Wind Partnership [Member]
Gain (Loss) on Investments	CAD 19		CAD 0	CAD 19
Equity Method Investment, Ownership Percentage	49.00%
Gain (Loss) On Investments After Tax	CAD 12

X

- Definition

The excess of the fair value of common stock over the holding value of subscription receipts converted during the accounting period.

+ References

No definition available.

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- Definition

This item represents the net total realized and unrealized after tax gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

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Including the current and noncurrent portions, the carrying value of convertible subordinated debt, as of the balance sheet date, initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. This form of debt can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder, and places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Subparagraph (SX 210.5-02(22))
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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

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The increase (decrease) during the reporting period in the capitalized cost of equity (based on assumed rate of return) and / or borrowed funds (based on interest rate) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments. As a result of this capitalization, net income is increased. This element pertains to certain regulated industries, such as public utilities.

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The increase (decrease) during the period in the carrying amount of accrued known and estimated losses incurred for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's' compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

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Amount of income related to nonoperating activities, classified as other.

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Amount of income (expense) related to nonoperating activities, classified as other.

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Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

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Stated interest rate of the subordinated debt.

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