DERIVATIVE INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2015

Notes To Consolidated Financial Statements [Abstract]

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

		As of December 31,
		2015						2014
		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 3:
	Eversource	$	16.7	$	(10.9)	$	5.8	$	16.2	$	(6.6)	$	9.6
	CL&P		16.7		(10.9)		5.8		16.1		(6.6)		9.5
	NSTAR Electric		-		-		-		0.1		-		0.1
Long-Term Derivative Assets:
Level 2:
	Eversource	$	0.1	$	-	$	0.1	$	-	$	-	$	-
Level 3:
	Eversource		62.0		(19.3)		42.7		93.5		(19.2)		74.3
	CL&P		60.7		(19.3)		41.4		93.5		(19.2)		74.3
	NSTAR Electric		1.3		-		1.3		-		-		-
Current Derivative Liabilities:
Level 2:
	Eversource	$	(5.8)	$	-	$	(5.8)	$	(9.8)	$	-	$	(9.8)
Level 3:
	Eversource		(92.3)		-		(92.3)		(90.0)		-		(90.0)
	CL&P		(91.8)		-		(91.8)		(88.5)		-		(88.5)
	NSTAR Electric		(0.5)		-		(0.5)		(1.5)		-		(1.5)
Long-Term Derivative Liabilities:
Level 2:
	Eversource	$	-	$	-	$	-	$	(0.3)	$	-	$	(0.3)
Level 3:
	Eversource		(337.1)		-		(337.1)		(409.3)		-		(409.3)
	CL&P		(336.2)		-		(336.2)		(406.2)		-		(406.2)
	NSTAR Electric		(0.9)		-		(0.9)		(3.1)		-		(3.1)

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

Fairvalueinputsliabilitiesquantitativeinformationtabletextblock

	As of December 31,
	2015						2014
		Range				Period Covered		Range				Period Covered
Capacity Prices:
Eversource	$	10.81	-	15.82	per kW-Month	2016 - 2026	$	5.30	-	12.98	per kW-Month	2016 - 2026
CL&P	$	10.81	-	12.60	per kW-Month	2019 - 2026	$	11.08	-	12.98	per kW-Month	2018 - 2026
NSTAR Electric	$	10.81	-	15.82	per kW-Month	2016 - 2019	$	5.30	-	11.10	per kW-Month	2016 - 2019
Forward Reserve:
Eversource, CL&P	$	2.00			per kW-Month	2016 - 2024	$	5.80	-	9.50	per kW-Month	2015 - 2024
REC Prices:
Eversource, NSTAR Electric	$	45	-	51	per REC	2016 - 2018	$	38	-	56	per REC	2015 - 2018

FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock

(Millions of Dollars)	Eversource		CL&P		NSTAR Electric
Derivatives, Net:
Fair Value as of January 1, 2014	$	(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)
Net Realized/Unrealized Losses Included in Regulatory Assets and Liabilities		(52.1)		(51.3)		(0.8)
Settlements		86.6		81.4		5.2
Fair Value as of December 31, 2015	$	(380.9)	$	(380.8)	$	(0.1)