DEBT Interest Rate Swap Agreements (Details) - USD ($)		1 Months Ended
	Mar. 31, 2016	Mar. 31, 2016	Feb. 29, 2016	Jan. 31, 2015	Oct. 31, 2014	Aug. 31, 2014	Mar. 01, 2016	Dec. 31, 2015
Derivative [Line Items]
Debt maturing within one year	$ 607,058,000	$ 607,058,000						$ 395,105,000
Notional amount	200,000,000	200,000,000	$ 75,000,000	$ 25,000,000	$ 25,000,000	$ 25,000,000	$ 50,000,000
Fixed rate				2.301%	3.075%	3.217%	1.743%
Weighted average fixed rate			1.687%
Recurring Basis | Fair Value, Inputs, Level 2 | Interest Rate Swap
Derivative [Line Items]
Derivative assets	359,000	359,000						112,000
Derivative liabilities	8,160,000	$ 8,160,000						$ 3,548,000
Interest Rate Swap
Derivative [Line Items]
Term of contract		10 years	10 years	10 years	10 years	10 years
Ineffectiveness recorded in the condensed consolidated statement of operations	0
ITC Holdings | Senior Notes, due September 30, 2016 | Unsecured Debt
Derivative [Line Items]
Debt maturing within one year	139,200,000	$ 139,200,000
ITC Holdings | Term Loan Credit Agreement, due September 30, 2016 | Unsecured Debt
Derivative [Line Items]
Debt maturing within one year	$ 160,900,000	$ 160,900,000