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Short Term Debt (Narrative) (Details) CAD in Millions, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2016 CAD | Dec. 31, 2016 USD ($) | Dec. 31, 2015 CAD
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 1,762 |  | CAD 18
Revolving Credit Facility [Member] | Tampa Electric Division [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 436 | $ 325 |
Line of Credit Facility, Expiration Date | Dec. 17, 2018 |  |
Revolving Credit Facility [Member] | TECO Energy Inc. and TECO Finance Inc. [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 403 | 300 |
Line of Credit Facility, Expiration Date | Dec. 17, 2018 |  |
Accounts Receivable Revolving Credit Facility | Tampa Electric Division [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 201 | 150 |
Line of Credit Facility, Expiration Date | Mar. 23, 2018 |  |
Accounts Receivable Revolving Credit Facility | New Mexico Gas Company [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 168 | 125 |
Line of Credit Facility, Expiration Date | Dec. 17, 2018 |  |
Finance Term Credit Facility [Member] | TECO Energy Inc. and TECO Finance Inc. [Member] |  |  |
Line of Credit Facility [Line Items] |  |  |
Line of Credit Facility, Maximum Borrowing Capacity | CAD 537 | $ 400 |
Line of Credit Facility, Expiration Date | Mar. 14, 2017 |  |

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- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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