Business Combination, Consideration, Cash Paid Minority Investor

No definition available.

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- Definition

Business Combination, Consideration, Cash Per Common Share

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Business Combination, Consideration, Stock Per Common Share

+ References

No definition available.

+ Details

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- Definition

Business Combination, Fee for Termination of Agreement

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Ownership Percentage of Acquirer Upon Completion of Merger

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Ownership Percentage of Minority Investor Upon Completion of Merger

+ 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

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e1043-128460

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

Name:	itc_AnticipatedBusinessMergerAxis=itc_TerminationFeeUponSpecifiedConditionsMember
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- Details

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- Details

Name:	dei_LegalEntityAxis=itc_GICPrivateLimitedMember
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- Details

Name:	dei_LegalEntityAxis=itc_FortisMember
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- Details

Name:	itc_AnticipatedBusinessMergerAxis=itc_TerminationFeeRelatedtoRegulatoryApprovalsorLegalMattersMember
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PROPOSED MERGER (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended	6 Months Ended
	Apr. 20, 2016	Feb. 09, 2016	Jun. 30, 2016	Jun. 30, 2016
External Legal, Advisory and Financial Services Fees
Proposed Merger
Merger related expenses			$ 12.4	$ 22.3
Certain Internal Labor and Associated Costs
Proposed Merger
Merger related expenses			$ 3.2	$ 6.3
Termination Fee Upon Specified Conditions
Proposed Merger
Fee for termination of agreement		$ 245.0
ITC Holdings
Proposed Merger
Cash per common share		$ 22.57
Fortis stock per common share		$ 0.7520
Ownership percentage of Fortis after close of merger		27.00%
GIC Private Limited
Proposed Merger
Ownership percentage of minority investor upon completion of merger	19.90%
Business acquisition, cash consideration	$ 1,228.0
Fortis \| Termination Fee Related to Regulatory Approvals or Legal Matters
Proposed Merger
Fee for termination of agreement		$ 280.0