MERGER OF NU AND NSTAR (Tables)

12 Months Ended

Dec. 31, 2012

Notes To Consolidated Financial Statements [Abstract]

Schedule of Business Acquisitions by Acquisition Equity Interest Issued or Issuable [Table Text Block]

NSTAR common shares outstanding as of April 9, 2012 (in thousands)*			103,696
Exchange ratio			1.312
NU common shares issued for NSTAR common shares outstanding (in thousands)			136,049
Closing price of NU common shares on April 9, 2012		$	36.79
Value of common shares issued (in millions)		$	5,005
Fair value of NU replacement stock-based compensation awards related to
	pre-merger service (in millions)		33
Total purchase price (in millions)		$	5,038

Schedule of Purchase Price Allocation

(Billions of Dollars)
Current Assets	$	0.7
Property Plant and Equipment, Net		5.1
Goodwill		3.2
Other Long-Term Assets, excluding Goodwill		2.1
Current Liabilities		(1.3)
Long-Term Liabilities		(2.7)
Long-Term Debt and Other Long-Term Obligations		(2.1)
Total Purchase Price	$	5.0

Business Acquisition, Pro Forma Information

	For the Years Ended December 31,
(Pro forma amounts in millions, except per share amounts)	2012		2011
Operating Revenues	$	7,004	$	7,361
Net Income Attributable to Controlling Interest		630		689
Basic EPS		2.00		2.20
Diluted EPS		1.99		2.19

Business Acquisition, Integration, Restructuring and Other Related Costs [Text Block]

		For the Years Ended December 31,
(Millions of Dollars)		2012		2011
Transaction and Other Costs		$	32	$	19
Settlement Agreement Impacts			60		-
Total After-Tax Non-Recurring Costs Excluded from
	Pro Forma Net Income Attributable to Controlling Interest	$	92	$	19

(Millions of Dollars)	NU		CL&P		NSTAR Electric		WMECO
Customer Rate Credits	$	46	$	25	$	15	$	3
Storm Costs Deferral Reduction		40		40		-		-
Establishment of Energy Efficiency Fund		15		-		-		-
Total Pre-Tax Settlement Agreement Impacts	$	101	$	65	$	15	$	3

Schedule Of Goodwill Text Block

		Electric		Electric		Natural Gas
		Distribution		Transmission		Distribution		Total
Balance as of December 31, 2011		$	0.0	$	0.0	$	0.3	$	0.3
	Merger with NSTAR		2.5		0.6		0.1		3.2
Balance as of December 31, 2012		$	2.5	$	0.6	$	0.4	$	3.5