Public Utilities, Approved Cost-Based Formula, Annual True-Up, Period

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- Definition

Public Utilities, Approved Cost-Based Formula, Period

+ References

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- Definition

Public Utilities, Number Of Utilities

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- Definition

Public Utilities, Recommended Return on Equity, Percentage

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- Definition

Amount of cash outflow to customers for refund payments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 13.A.4(a))
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

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- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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The total number of new claims filed pertaining to a loss contingency during the period.

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- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

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- Definition

Percentage of public utility's approved return on equity.

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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.

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Nature of Regulation - ITC (Details) - ITC $ in Millions	1 Months Ended	5 Months Ended	12 Months Ended			16 Months Ended
Nature of Regulation - ITC (Details) - ITC $ in Millions	Feb. 28, 2017 USD ($)	Sep. 30, 2016 company	Dec. 31, 2016 USD ($)	Dec. 31, 2015	Dec. 31, 2013 complaint	May 30, 2016	Feb. 28, 2015
ROE refund liability
Public Utilities, General Disclosures [Line Items]
Complaints (number) \| complaint					2
Estimated potential refund			$ 258
ROE refund liability \| Minimum
Public Utilities, General Disclosures [Line Items]
Estimated potential refund			221
ROE refund liability \| Maximum
Public Utilities, General Disclosures [Line Items]
Estimated potential refund			$ 258
Subsequent event \| ROE refund liability, initial complaint
Public Utilities, General Disclosures [Line Items]
Refunds, including interest	$ 119
FERC
Public Utilities, General Disclosures [Line Items]
Approved cost-based formula (years)			1 year
Approved cost-based formula, annual true-up (period)			2 years
Capital structure of common equity (percent)			60.00%	60.00%
ROE (percent)		12.38%					10.32%
Recommended ROE (percent)						9.70%
Number of utilities \| company		3
FERC \| Maximum
Public Utilities, General Disclosures [Line Items]
ROE (percent)		13.88%					11.35%
Recommended ROE (percent)						10.68%
FERC \| ROE refund liability
Public Utilities, General Disclosures [Line Items]
Complaints (number) \| complaint					2