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Segment Disclosures Disclosure of operating segments (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of operating segments [line items] |  |  |
Revenues | $ 2,249 | $ 2,307 | $ 2,397
Fuel and purchased power (Note 6) | 1,100 | 1,016 | 963
Gross margin | 1,149 | 1,291 | 1,434
Depreciation and amortization | 574 | 635 | 601
Asset impairment charges (reversals) (Note 7) | 73 | 20 | 28
Restructuring provision | 0 | 0 | 1
Taxes, other than income taxes | 31 | 30 | 31
Finance lease income | 8 | 54 | 66
Gain on sale of assets and other | 1 | 2 | 4
Net interest expense (Note 10) | (250) | (247) | (229)
Foreign exchange gain (loss) | (15) | (1) | (5)
Earnings (loss) before income taxes | (96) | (54) | 314
Goodwill (Note 18) | 464 | 463 |
Property, plant and equipment (Note 17) | 6,164 | 6,578 | 6,824
Intangible assets (Note 19) | 373 | 364 | 355
Other assets (Note 20) | 234 | 237 |
Property, plant and equipment expenditures | 277 | 338 | 358
Purchase of intangible assets | 20 | 51 | 21
Mine depreciation | 136 | 73 | 63
Adjustments for depreciation and amortisation expense | 710 | 708 | 664
Canada |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 1,573 | 1,663 | 1,828
Goodwill (Note 18) | 417 | 417 |
Property, plant and equipment (Note 17) | 4,953 | 5,353 |
Intangible assets (Note 19) | 273 | 297 |
Other assets (Note 20) | 101 | 105 |
US |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 511 | 509 | 450
Goodwill (Note 18) | 47 | 46 |
Property, plant and equipment (Note 17) | 657 | 619 |
Intangible assets (Note 19) | 59 | 25 |
Other assets (Note 20) | 50 | 43 |
Australia |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 165 | 135 | 119
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 554 | 606 |
Intangible assets (Note 19) | 41 | 42 |
Other assets (Note 20) | 83 | 89 |
Wind and Solar |  |  |
Disclosure of operating segments [line items] |  |  |
Income from government grants | 16 | 18 | 19
Reportable segments [member] |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 2,249 | 2,307 | 2,397
Fuel and purchased power (Note 6) | 1,100 | 1,016 | 963
Gross margin | 1,149 | 1,291 | 1,434
Operations, maintenance, and administration (Note 5) | 515 | 517 | 489
Depreciation and amortization | 574 | 635 | 601
Asset impairment charges (reversals) (Note 7) | 73 | 20 | 28
Taxes, other than income taxes | 31 | 30 | 31
Profit (loss) from operating activities | (204) | (49) | (193)
Operating income | 160 | 138 | 478
Finance lease income | 8 | 54 | 66
Gain on sale of assets and other | 1 | 2 | 4
Net interest expense (Note 10) | (250) | (247) | (229)
Foreign exchange gain (loss) | (15) | (1) | (5)
Earnings (loss) before income taxes | (96) | (54) | 314
Goodwill (Note 18) | 464 | 463 |
Property, plant and equipment (Note 17) | 6,164 | 6,578 |
Intangible assets (Note 19) | 373 | 364 |
Property, plant and equipment expenditures | 277 | 338 | 358
Purchase of intangible assets | 20 | 51 | 21
Reportable segments [member] | Canadian Coal |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 912 | 999 | 1,048
Fuel and purchased power (Note 6) | 666 | 585 | 451
Gross margin | 246 | 414 | 597
Operations, maintenance, and administration (Note 5) | 171 | 192 | 178
Depreciation and amortization | 241 | 317 | 242
Asset impairment charges (reversals) (Note 7) | 38 | 20 | 0
Taxes, other than income taxes | 13 | 13 | 13
Profit (loss) from operating activities | (198) | (40) | (2)
Operating income | (19) | (88) | 166
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 2,587 | 2,902 |
Intangible assets (Note 19) | 81 | 91 |
Property, plant and equipment expenditures | 101 | 116 | 159
Purchase of intangible assets | 3 | 5 | 3
Reportable segments [member] | United States Coal |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 442 | 435 | 354
Fuel and purchased power (Note 6) | 314 | 293 | 281
Gross margin | 128 | 142 | 73
Operations, maintenance, and administration (Note 5) | 61 | 51 | 54
Depreciation and amortization | 74 | 73 | 61
Asset impairment charges (reversals) (Note 7) | 0 | 0 | 0
Taxes, other than income taxes | 5 | 4 | 4
Profit (loss) from operating activities | 0 | 0 | 0
Operating income | (12) | 14 | (46)
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 332 | 370 |
Intangible assets (Note 19) | 7 | 7 |
Property, plant and equipment expenditures | 14 | 35 | 15
Purchase of intangible assets | 0 | 1 | 1
Reportable segments [member] | Canadian Gas |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 232 | 261 | 402
Fuel and purchased power (Note 6) | 96 | 101 | 185
Gross margin | 136 | 160 | 217
Operations, maintenance, and administration (Note 5) | 48 | 50 | 54
Depreciation and amortization | 43 | 38 | 100
Asset impairment charges (reversals) (Note 7) | 0 | 0 | 0
Taxes, other than income taxes | 1 | 1 | 1
Profit (loss) from operating activities | 0 | (9) | (191)
Operating income | 44 | 80 | 253
Finance lease income | 8 | 11 | 14
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 391 | 416 |
Intangible assets (Note 19) | 4 | 3 |
Property, plant and equipment expenditures | 21 | 31 | 11
Purchase of intangible assets | 0 | 0 | 1
Reportable segments [member] | Australian Gas |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 165 | 135 | 119
Fuel and purchased power (Note 6) | 8 | 14 | 20
Gross margin | 157 | 121 | 99
Operations, maintenance, and administration (Note 5) | 37 | 31 | 25
Depreciation and amortization | 49 | 37 | 17
Asset impairment charges (reversals) (Note 7) | 0 | 0 | 0
Taxes, other than income taxes | 0 | 0 | 1
Profit (loss) from operating activities | 0 | 0 | 0
Operating income | 71 | 53 | 56
Finance lease income | 0 | 43 | 52
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 554 | 606 |
Intangible assets (Note 19) | 41 | 42 |
Property, plant and equipment expenditures | 6 | 114 | 107
Purchase of intangible assets | 0 | 29 | 0
Reportable segments [member] | Wind and Solar |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 282 | 287 | 272
Fuel and purchased power (Note 6) | 17 | 17 | 18
Gross margin | 265 | 270 | 254
Operations, maintenance, and administration (Note 5) | 50 | 48 | 52
Depreciation and amortization | 110 | 111 | 119
Asset impairment charges (reversals) (Note 7) | 12 | 0 | 28
Taxes, other than income taxes | 8 | 8 | 8
Profit (loss) from operating activities | (6) | 0 | (1)
Operating income | 91 | 103 | 48
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 175 | 174 |
Property, plant and equipment (Note 17) | 1,799 | 1,764 |
Intangible assets (Note 19) | 173 | 149 |
Property, plant and equipment expenditures | 117 | 20 | 16
Purchase of intangible assets | 0 | 0 | 0
Reportable segments [member] | Hydro |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 156 | 121 | 126
Fuel and purchased power (Note 6) | 6 | 6 | 8
Gross margin | 150 | 115 | 118
Operations, maintenance, and administration (Note 5) | 38 | 37 | 33
Depreciation and amortization | 30 | 31 | 33
Asset impairment charges (reversals) (Note 7) | 0 | 0 | 0
Taxes, other than income taxes | 3 | 3 | 3
Profit (loss) from operating activities | 0 | 0 | 0
Operating income | 79 | 44 | 49
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 259 | 259 |
Property, plant and equipment (Note 17) | 481 | 497 |
Intangible assets (Note 19) | 4 | 3 |
Property, plant and equipment expenditures | 16 | 16 | 43
Purchase of intangible assets | 0 | 0 | 0
Reportable segments [member] | Energy Marketing |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | 67 | 69 | 76
Fuel and purchased power (Note 6) | 0 | 0 | 0
Gross margin | 67 | 69 | 76
Operations, maintenance, and administration (Note 5) | 24 | 24 | 24
Depreciation and amortization | 2 | 2 | 3
Asset impairment charges (reversals) (Note 7) | 0 | 0 | 0
Taxes, other than income taxes | 0 | 0 | 0
Profit (loss) from operating activities | 0 | 0 | 0
Operating income | 41 | 43 | 49
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 30 | 30 |
Property, plant and equipment (Note 17) | 1 | 1 |
Intangible assets (Note 19) | 11 | 13 |
Property, plant and equipment expenditures | 0 | 0 | 0
Purchase of intangible assets | 0 | 0 | 0
Reportable segments [member] | Corporate |  |  |
Disclosure of operating segments [line items] |  |  |
Revenues | (7) | 0 | 0
Fuel and purchased power (Note 6) | (7) | 0 | 0
Gross margin | 0 | 0 | 0
Operations, maintenance, and administration (Note 5) | 86 | 84 | 69
Depreciation and amortization | 25 | 26 | 26
Asset impairment charges (reversals) (Note 7) | 23 | 0 | 0
Taxes, other than income taxes | 1 | 1 | 1
Profit (loss) from operating activities | 0 | 0 | 1
Operating income | (135) | (111) | (97)
Finance lease income | 0 | 0 | 0
Goodwill (Note 18) | 0 | 0 |
Property, plant and equipment (Note 17) | 19 | 22 |
Intangible assets (Note 19) | 52 | 56 |
Property, plant and equipment expenditures | 2 | 6 | 7
Purchase of intangible assets | $ 17 | $ 16 | $ 16

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