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Accounts Receivable and Other Current Assets - Narrative (Details) CAD in Millions, $ in Millions | Dec. 31, 2016 CAD | Dec. 31, 2015 CAD | Apr. 30, 2015 USD ($) | Apr. 30, 2015 CAD
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Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Assets held for sale | CAD 0 | CAD 38 |  |
UNS Energy |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Assets held for sale |  |  | $ 21 | CAD 29
Interest for sale (percentage) |  | 17.05% |  |
Walden Hydroelectric Power Plant Assets | NON-REGULATED |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Assets held for sale |  | CAD 9 |  |

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- Definition Jointly Owned Utility Plant, Proportionate Ownership Share, Available For Sale + References No definition available. + Details
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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. + References No definition available. + Details
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- Definition Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 15 -Paragraph 4 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=6390208&loc=d3e400-110220 + Details
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- Details
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- Details
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- Details
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