PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Tables)

12 Months Ended

Dec. 31, 2014

Notes To Consolidated Financial Statements [Abstract]

Schedule of Public Utility Property, Plant, and Equipment [Text Block]

NU		As of December 31,
(Millions of Dollars)		2014		2013
Distribution - Electric		$	12,495.2	$	11,950.2
Distribution - Natural Gas			2,595.4		2,425.9
Transmission			6,930.7		6,412.5
Generation			1,170.9		1,152.3
Electric and Natural Gas Utility			23,192.2		21,940.9
Other (1)			551.3		508.7
Property, Plant and Equipment, Gross			23,743.5		22,449.6
Less: Accumulated Depreciation
	Electric and Natural Gas Utility		(5,777.8)		(5,387.0)
	Other		(231.8)		(196.2)
Total Accumulated Depreciation			(6,009.6)		(5,583.2)
Property, Plant and Equipment, Net			17,733.9		16,866.4
Construction Work in Progress			913.1		709.8
Total Property, Plant and Equipment, Net		$	18,647.0	$	17,576.2

	As of December 31,
	2014								2013
			NSTAR								NSTAR
(Millions of Dollars)	CL&P		Electric		PSNH		WMECO		CL&P		Electric		PSNH		WMECO
Distribution	$	5,158.8	$	4,895.5	$	1,696.7	$	784.2	$	4,930.7	$	4,694.7	$	1,608.2	$	756.6
Transmission		3,274.0		1,928.5		789.7		891.0		3,071.9		1,772.3		695.7		826.4
Generation		-		-		1,136.5		34.4		-		-		1,131.2		21.1
Property, Plant and Equipment, Gross		8,432.8		6,824.0		3,622.9		1,709.6		8,002.6		6,467.0		3,435.1		1,604.1
Less: Accumulated Depreciation		(1,928.0)		(1,761.4)		(1,090.0)		(297.4)		(1,804.1)		(1,631.3)		(1,021.8)		(271.5)
Property, Plant and Equipment, Net		6,504.8		5,062.6		2,532.9		1,412.2		6,198.5		4,835.7		2,413.3		1,332.6
Construction Work in Progress		304.9		272.8		102.9		49.1		252.8		208.2		54.3		48.5
Total Property, Plant and Equipment, Net	$	6,809.7	$	5,335.4	$	2,635.8	$	1,461.3	$	6,451.3	$	5,043.9	$	2,467.6	$	1,381.1

(Percent)	2014		2013		2012
NU	3.0	%	2.8	%	2.5	%
CL&P	2.7		2.5		2.5
NSTAR Electric	3.0		2.9		2.8
PSNH	3.0		3.0		3.0
WMECO	3.3		2.9		3.3

The following table summarizes average useful lives of depreciable assets:
	Average Depreciable Life
(Years)	NU		CL&P		NSTAR Electric		PSNH		WMECO
Distribution		34.9		37.5		32.3		32.3		30.9
Transmission		42.5		39.8		44.0		43.7		49.9
Generation		31.9		-		-		32.1		25.0
Other		14.2		-		-		-		-