DERIVATIVE INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2014

Notes To Consolidated Financial Statements [Abstract]

Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value Text Block

		As of December 31,
		2014						2013
		Commodity Supply				Net Amount		Commodity Supply				Net Amount
		and Price Risk				Recorded as		and Price Risk					Recorded as
(Millions of Dollars)		Management		Netting (1)		a Derivative		Management		Netting (1)		a Derivative
Current Derivative Assets:
Level 2:
	NU	$	-	$	-	$	-	$	1.9	$	(0.3)	$	1.6
Level 3:
	NU		16.2		(6.6)		9.6		18.4		(9.8)		8.6
	CL&P		16.1		(6.6)		9.5		17.1		(9.8)		7.3
	NSTAR Electric		0.1		-		0.1		1.2		-		1.2
Long-Term Derivative Assets:
Level 2:
	NU	$	-	$	-	$	-	$	0.2	$	-	$	0.2
Level 3:
	NU		93.5		(19.2)		74.3		116.2		(42.2)		74.0
	CL&P		93.5		(19.2)		74.3		113.6		(42.2)		71.4
Current Derivative Liabilities:
Level 2:
	NU	$	(9.8)	$	-	$	(9.8)	$	-	$	-	$	-
Level 3:
	NU		(90.0)		-		(90.0)		(93.7)		-		(93.7)
	CL&P		(88.5)		-		(88.5)		(92.2)		-		(92.2)
	NSTAR Electric		(1.5)		-		(1.5)		(1.5)		-		(1.5)
Long-Term Derivative Liabilities:
Level 2:
	NU	$	(0.3)	$	-	$	(0.3)	$	-	$	-	$	-
Level 3:
	NU		(409.3)		-		(409.3)		(624.1)		-		(624.1)
	CL&P		(406.2)		-		(406.2)		(617.1)		-		(617.1)
	NSTAR Electric		(3.1)		-		(3.1)		(7.0)		-		(7.0)

Schedule Of Derivative Instruments Gain Loss In Statement Of Financial Performance Text Block

		Gain/(Loss) Recognized on Derivatives
(Millions of Dollars)		For the Years Ended December 31,
NU		2014		2013		2012
Balance Sheets:
	Regulatory Assets and Liabilities	$	134.4	$	160.6	$	(29.0)
Statements of Income:
	Purchased Power, Fuel and Transmission		-		1.0		(0.7)

Fairvalueinputsliabilitiesquantitativeinformationtabletextblock

	As of December 31,
	2014							2013
		Range					Period Covered		Range					Period Covered
Energy Prices:
NU	$	52			per MWh		2020	$	49	-	77	per MWh		2018 - 2029
CL&P	$	52			per MWh		2020	$	56	-	58	per MWh		2018 - 2029
Capacity Prices:
NU	$	5.30	-	12.98		per kW-Month	2016 - 2026	$	5.07	-	11.82		per kW-Month	2017 - 2029
CL&P	$	11.08	-	12.98		per kW-Month	2018 - 2026	$	5.07	-	10.42		per kW-Month	2017 - 2026
NSTAR Electric	$	5.30	-	11.10		per kW-Month	2016 - 2019	$	5.07	-	7.38		per kW-Month	2017 - 2019
Forward Reserve:
NU, CL&P	$	5.80	-	9.50		per kW-Month	2015 - 2024	$	3.30				per kW-Month	2014 - 2024
REC Prices:
NU	$	38	-	56	per REC		2015 - 2018	$	36	-	87		per REC	2014 - 2029
NSTAR Electric	$	38	-	56	per REC		2015 - 2018	$	36	-	70		per REC	2014 - 2018

FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock

(Millions of Dollars)		NU		CL&P		NSTAR Electric
Derivatives, Net:
Fair Value as of January 1, 2013		$	(878.6)	$	(866.2)	$	(14.9)
Net Realized/Unrealized Gains Included in:
	Net Income (1)		10.9		-		-
	Regulatory Assets and Liabilities		158.3		148.9		3.5
Settlements			74.2		86.7		4.1
Fair Value as of December 31, 2013		$	(635.2)	$	(630.6)	$	(7.3)
Net Realized/Unrealized Gains Included in Regulatory Assets and Liabilities			141.3		139.7		4.3
Settlements			78.5		80.0		(1.5)
Fair Value as of December 31, 2014		$	(415.4)	$	(410.9)	$	(4.5)