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Accumulated Other Comprehensive Income (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - CAD CAD in Millions | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Non-regulated fuel for generation and purchased power | CAD 313 | CAD 336
Income (Loss) from Equity Method Investments | 100 | 108
Operating, maintenance and general | 1,137 | 666
Other Income (Expense) | 174 | 141
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest | 244 | 545
Income tax expense (recovery) | (22) | 93
Net income | 266 | 452
Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Net income | 65 | 114
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest | 11 | 5
Income tax expense (recovery) | 0 | 2
Net income | 11 | 7
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Power and Gas Swaps [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Non-regulated fuel for generation and purchased power | (2) | (5)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Interest Rate Swap [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Income (Loss) from Equity Method Investments | 1 | 1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Foreign Exchange Forward [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Regulated | 12 | 9
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest | 15 | 115
Income tax expense (recovery) | (3) | (8)
Net income | 12 | 107
Reclassification out of Accumulated Other Comprehensive Income [Member] | Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Operating, maintenance and general | 41 | 50
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Operating, maintenance and general | (9) | (7)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Transition Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Pension and Other Postretirement Benefit Expense | (17) | 72
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Available For Sale Securities Gain Loss Including Portion Attributable To Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Other Income (Expense) | (4) | 0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest | (4) | 0
Income tax expense (recovery) | 0 | 0
Net income | (4) | 0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |
Equity Method Investment, Realized Gain (Loss) on Disposal | 54 | 0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest | 54 | 0
Income tax expense (recovery) | (8) | 0
Net income | CAD 46 | CAD 0

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- Definition Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=68072869&loc=d3e41242-110953 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(10)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(15)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(8)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 + Details
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