COMMITMENTS AND CONTINGENCIES (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 Subcontractor
Connecticut Yankee Atomic Power Company [Member]
Site Contingency [Line Items]
Percentage stock ownership share in CT Yankee atomic power company (in hundredths)	9.50%
Carrying value of stock in CT Yankee atomic power company	$ 0.1
DOE spent fuel litigation [Abstract]
Damages awarded to CT Yankee for spent fuel related costs	39.7
Entity's share of amount awarded to CT Yankee atomic power company	3.8
Second set of damage claims sent by CT Yankee relating to failure to remove spent atomic fuel	135
Entity's share of second set of damage claims	12.8
Mill River New Haven Connecticut Site [Member]
Site Decontamination, Demolition and Remediation Costs [Abstract]
Amount placed in escrow for estimated remediation	1.9
Remaining amount of escrow	0.1
New Haven Harbor Station Site [Member]
Site Decontamination, Demolition and Remediation Costs [Abstract]
Site contingency, liability accrued	3.2
Mill Street Greenfield Massachusetts Site [Member]
Site Decontamination, Demolition and Remediation Costs [Abstract]
Site contingency, liability accrued	4.3
East Street Site Pittsfield Massachusetts [Member]
Site Decontamination, Demolition and Remediation Costs [Abstract]
Site contingency, liability accrued	2.0
Middletown/Norwalk Transmission Project [Member]
Middletown/Norwalk Transmission Project [Abstract]
Amount sought for change order requests	33.3
Percentage of general contractor mark-up on approved subcontractor change order claims (in hundredths)	10.00%
Amount of general contractor mark up on approved subcontractor change order claims	2.3
Subcontractors responsible for civil construction	2
Revised estimate for change order requests	7.7
Amount in Memorandum of Decision issued by the court for the company to pay to contractor	$ 1.3