SEGMENT INFORMATION (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
OPERATING REVENUES:
Operating revenues		$ 298	$ 280
INCOME (LOSS) BEFORE INCOME TAXES:
Income before income taxes		127	104
NET INCOME:
NET INCOME		80	65
TOTAL ASSETS:
Assets		8,420		$ 8,223
Regulated operations
OPERATING REVENUES:
Operating revenues		305	280
INCOME (LOSS) BEFORE INCOME TAXES:
Income before income taxes		162	153
NET INCOME:
NET INCOME		99	94
TOTAL ASSETS:
Assets		8,355		8,162
ITC Holdings and other
INCOME (LOSS) BEFORE INCOME TAXES:
Income before income taxes		(35)	(49)
NET INCOME:
NET INCOME		80	65
TOTAL ASSETS:
Assets		4,589		4,503
Intercompany eliminations
OPERATING REVENUES:
Operating revenues		(7)	0
NET INCOME:
NET INCOME		(99)	$ (94)
TOTAL ASSETS:
Assets	[1]	$ (4,524)		$ (4,442)

[1] Reconciliation of total assets results primarily from differences in the netting of deferred tax assets and liabilities at our subsidiaries in the Regulated Operating Subsidiaries segment as compared to the classification in our condensed consolidated statements of financial position.