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Regulatory Assets and Liabilities (Other) (Details) CAD in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CAD	Dec. 31, 2015 CAD
Regulatory Assets [Line Items]
Regulatory Assets		CAD 1,322	CAD 699
TECO Energy Inc [Member]
Regulatory Assets [Line Items]
Public Utilities Annual Bill Reduction To Customers | $	$ 4
TECO Energy Inc [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets		CAD 11
Tampa Electric Division [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Regulatory Assets			CAD 11

X

- References

No definition available.

+ Details

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Namespace Prefix:	ema_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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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

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

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- Details

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- Details

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- Details

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