PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Tables)

12 Months Ended

Dec. 31, 2013

Notes To Consolidated Financial Statements [Abstract]

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

NU		As of December 31,
(Millions of Dollars)		2013		2012
Distribution - Electric		$	11,950.2	$	11,438.2
Distribution - Natural Gas			2,425.9		2,274.2
Transmission			6,412.5		5,541.1
Generation			1,152.3		1,146.6
Electric and Natural Gas Utility			21,940.9		20,400.1
Other (1)			508.7		429.3
Property, Plant and Equipment, Gross			22,449.6		20,829.4
Less: Accumulated Depreciation
	Electric and Natural Gas Utility		(5,387.0)		(5,065.1)
	Other		(196.2)		(171.5)
Total Accumulated Depreciation			(5,583.2)		(5,236.6)
Property, Plant and Equipment, Net			16,866.4		15,592.8
Construction Work in Progress			709.8		1,012.2
Total Property, Plant and Equipment, Net		$	17,576.2	$	16,605.0

	As of December 31,
	2013								2012
			NSTAR								NSTAR
(Millions of Dollars)	CL&P		Electric		PSNH		WMECO		CL&P		Electric		PSNH		WMECO
Distribution	$	4,930.7	$	4,694.7	$	1,608.2	$	756.6	$	4,691.3	$	4,539.9	$	1,520.1	$	724.2
Transmission		3,071.9		1,772.3		695.7		826.4		2,796.1		1,529.7		599.2		583.7
Generation		-		-		1,131.2		21.1		-		-		1,125.5		21.1
Property, Plant and
Equipment, Gross		8,002.6		6,467.0		3,435.1		1,604.1		7,487.4		6,069.6		3,244.8		1,329.0
Less: Accumulated Depreciation		(1,804.1)		(1,631.3)		(1,021.8)		(271.5)		(1,698.1)		(1,540.1)		(954.0)		(252.1)
Property, Plant and Equipment, Net		6,198.5		4,835.7		2,413.3		1,332.6		5,789.3		4,529.5		2,290.8		1,076.9
Construction Work in Progress		252.8		208.2		54.3		48.5		363.7		205.8		61.7		213.6
Total Property, Plant and
Equipment, Net	$	6,451.3	$	5,043.9	$	2,467.6	$	1,381.1	$	6,153.0	$	4,735.3	$	2,352.5	$	1,290.5

(Percent)	2013		2012		2011
NU		2.8		2.5		2.6
CL&P		2.5		2.5		2.4
NSTAR Electric		2.9		2.8		3.0
PSNH		3.0		3.0		2.9
WMECO		2.9		3.3		2.9

The following table summarizes average useful lives of depreciable assets:
	Average Depreciable Life
(Years)	NU		CL&P		NSTAR Electric		PSNH		WMECO
Distribution		36.1		42.0		32.9		32.7		29.8
Transmission		43.0		39.6		47.2		42.3		49.5
Generation		32.2		-		-		32.4		25.0
Other		14.6		-		-		-		-