MARKETABLE SECURITIES (Tables)

9 Months Ended

Sep. 30, 2013

Notes To Consolidated Financial Statements [Abstract]

Schedule Of Available For Sale Securities Reconciliation [Table TextBlock]

		As of September 30, 2013
				Pre-Tax		Pre-Tax
		Amortized		Unrealized		Unrealized
(Millions of Dollars)		Cost		Gains(1)		Losses(1)		Fair Value
NU
	Debt Securities (2)	$	306.1	$	1.5	$	(3.8)	$	303.8
	Equity Securities (2)		164.0		40.9		-		204.9
WMECO
	Debt Securities		57.8		-		-		57.8
		As of December 31, 2012
				Pre-Tax		Pre-Tax
		Amortized		Unrealized		Unrealized
(Millions of Dollars)		Cost		Gains(1)		Losses(1)		Fair Value
NU
	Debt Securities (2)	$	266.6	$	13.3	$	(0.1)	$	279.8
	Equity Securities (2)		145.5		20.0		-		165.5
WMECO
	Debt Securities		57.7		0.1		(0.1)		57.7

Investments Classified by Contractual Maturity Date [Table Text Block]

	NU				WMECO
	Amortized				Amortized
(Millions of Dollars)	Cost		Fair Value		Cost		Fair Value
Less than one year (1)	$	67.1	$	65.3	$	24.4	$	24.6
One to five years		76.0		76.6		26.4		26.3
Six to ten years		58.4		57.3		2.5		2.5
Greater than ten years		104.6		104.6		4.5		4.4
Total Debt Securities	$	306.1	$	303.8	$	57.8	$	57.8

Fair Value Heirarchy [Table Text Block]

			NU				WMECO
			As of				As of
(Millions of Dollars)			September 30, 2013		December 31, 2012		September 30, 2013		December 31, 2012
Level 1:
	Mutual Funds and Equities		$	259.2	$	212.5	$	-	$	-
	Money Market Funds			40.0		40.2		2.8		5.2
Total Level 1			$	299.2	$	252.7	$	2.8	$	5.2
Level 2:
	U.S. Government Issued Debt Securities
		(Agency and Treasury)	$	74.9	$	69.9	$	16.6	$	18.7
	Corporate Debt Securities			48.9		33.0		15.1		7.0
	Asset-Backed Debt Securities			30.4		28.5		9.6		10.9
	Municipal Bonds			93.7		93.8		8.8		11.6
	Other Fixed Income Securities			15.9		14.4		4.9		4.3
Total Level 2			$	263.8	$	239.6	$	55.0	$	52.5
Total Marketable Securities			$	563.0	$	492.3	$	57.8	$	57.7