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Description of Business - Non-Regulated - Energy Infrastructure (Details) | 12 Months Ended
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Dec. 31, 2016 station MW Bcf
BECOL | Hydroelectric Power Generation |
Public Utilities, General Disclosures [Line Items] |
Generating capacity (MW) | 51
Long-term contract for electric power, term | 50 years
Generating facilities | station | 3
Waneta Partnership |
Public Utilities, General Disclosures [Line Items] |
Long-term contract for electric power, term | 40 years
Waneta Partnership | Hydroelectric Power Generation |
Public Utilities, General Disclosures [Line Items] |
Generating capacity (MW) | 335
Waneta Partnership |
Public Utilities, General Disclosures [Line Items] |
Controlling ownership interest (percent) | 51.00%
Generating capacity (MW) | 335
Noncontrolling ownership (percent) | 49.00%
Aitken Creek | Aitken Creek Gas Storage ULC |
Public Utilities, General Disclosures [Line Items] |
Controlling ownership interest (percent) | 93.80%
Generating capacity (billion cubic feet) | Bcf | 77
Walden |
Public Utilities, General Disclosures [Line Items] |
Generating capacity (MW) | 16

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