CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Operating Revenues	$ 1,892,590	$ 1,861,529	$ 5,523,475	$ 4,589,835
Operating Expenses:
Purchased Power and Transmission	645,881	602,751	1,881,992	1,540,110
Operations and Maintenance	386,700	395,531	1,089,960	1,187,471
Depreciation	149,105	144,475	463,635	369,798
Amortization of Regulatory Assets/(Liabilities), Net	70,046	43,835	178,668	74,851
Amortization of Rate Reduction Bonds	0	43,044	42,581	102,144
Energy Efficiency Programs	106,097	98,326	306,010	209,089
Taxes Other Than Income Taxes	135,499	120,662	391,846	319,559
Total Operating Expenses	1,493,328	1,448,624	4,354,692	3,803,022
Operating Income	399,262	412,905	1,168,783	786,813
Interest Expense:
Interest on Long-Term Debt	84,911	86,459	256,205	233,352
Interest on Rate Reduction Bonds	0	1,681	422	5,168
Other Interest	2,565	2,221	(6,044)	7,336
Total Interest Expense	87,476	90,361	250,583	245,856
Other Income/(Loss), Net	8,945	4,324	21,655	14,904
Income Before Income Tax Expense	320,731	326,868	939,855	555,861
Income Tax Expense	109,351	117,360	325,442	199,379
Net Income	211,380	209,508	614,413	356,482
Net Income Attributable to Noncontrolling Interests	1,879	1,880	5,803	5,253
Net Income Attributable to Controlling Interests	209,501	207,628	608,610	351,229
Diluted Earnings Per Common Share	$ 0.66	$ 0.66	$ 1.93	$ 1.32
Basic Earnings Per Common Share	$ 0.66	$ 0.66	$ 1.93	$ 1.33
Common Stock Dividends Per Share Declared	$ 0.37	$ 0.34	$ 1.10	$ 0.97
Weighted Average Common Shares Outstanding:
Basic	315,291,346	314,806,441	315,191,752	264,636,636
Diluted	316,218,239	315,805,796	316,061,131	265,353,377
The Connecticut Light And Power Company [Member]
Operating Revenues	648,420	658,111	1,841,846	1,812,218
Operating Expenses:
Purchased Power and Transmission	253,152	241,046	667,266	658,743
Operations and Maintenance	127,104	141,913	359,759	480,286
Depreciation	44,786	41,863	132,356	124,451
Amortization of Regulatory Assets/(Liabilities), Net	(27)	8,656	11,223	19,912
Energy Efficiency Programs	24,544	25,237	68,211	68,205
Taxes Other Than Income Taxes	64,979	59,687	182,676	168,667
Total Operating Expenses	514,538	518,402	1,421,491	1,520,264
Operating Income	133,882	139,709	420,355	291,954
Interest Expense:
Interest on Long-Term Debt	32,845	31,429	98,163	94,646
Other Interest	2,439	2,162	801	6,223
Total Interest Expense	35,284	33,591	98,964	100,869
Other Income/(Loss), Net	3,861	2,889	10,946	8,636
Income Before Income Tax Expense	102,459	109,007	332,337	199,721
Income Tax Expense	36,136	34,121	113,149	63,917
Net Income	66,323	74,886	219,188	135,804
NSTAR Electric Company [Member]
Operating Revenues	753,879	693,653	1,916,557	1,784,755
Operating Expenses:
Purchased Power and Transmission	255,244	222,753	659,140	622,265
Operations and Maintenance	97,069	83,329	277,261	340,547
Depreciation	45,441	42,494	136,323	127,692
Amortization of Regulatory Assets/(Liabilities), Net	72,740	41,888	173,289	87,912
Amortization of Rate Reduction Bonds	0	22,581	15,054	67,742
Energy Efficiency Programs	58,798	55,969	161,180	138,360
Taxes Other Than Income Taxes	32,610	30,520	95,275	89,689
Total Operating Expenses	561,902	499,534	1,517,522	1,474,207
Operating Income	191,977	194,119	399,035	310,548
Interest Expense:
Interest on Long-Term Debt	19,860	22,386	59,261	66,953
Interest on Rate Reduction Bonds	0	853	399	3,106
Other Interest	(1,324)	(4,704)	(8,011)	(16,137)
Total Interest Expense	18,536	18,535	51,649	53,922
Other Income/(Loss), Net	2,126	551	3,275	1,778
Income Before Income Tax Expense	175,567	176,135	350,661	258,404
Income Tax Expense	68,558	69,373	137,499	102,220
Net Income	107,009	106,762	213,162	156,184
Public Service Company Of New Hampshire [Member]
Operating Revenues	218,608	256,949	708,550	755,051
Operating Expenses:
Purchased Power and Transmission	46,668	76,008	197,765	239,173
Operations and Maintenance	69,477	67,547	191,606	200,960
Depreciation	22,919	22,264	68,433	65,282
Amortization of Regulatory Assets/(Liabilities), Net	225	(6,356)	(1,745)	(6,179)
Amortization of Rate Reduction Bonds	0	16,112	19,748	43,855
Energy Efficiency Programs	3,990	4,030	11,036	10,824
Taxes Other Than Income Taxes	18,706	16,046	52,640	47,406
Total Operating Expenses	161,985	195,651	539,483	601,321
Operating Income	56,623	61,298	169,067	153,730
Interest Expense:
Interest on Long-Term Debt	10,345	11,434	32,951	34,537
Interest on Rate Reduction Bonds	0	564	(154)	2,366
Other Interest	521	609	1,384	1,301
Total Interest Expense	10,866	12,607	34,181	38,204
Other Income/(Loss), Net	792	(353)	2,454	2,237
Income Before Income Tax Expense	46,549	48,338	137,340	117,763
Income Tax Expense	18,196	21,106	52,797	48,037
Net Income	28,353	27,232	84,543	69,726
Western Massachusetts Electric Company [Member]
Operating Revenues	121,795	112,470	361,763	333,331
Operating Expenses:
Purchased Power and Transmission	38,797	32,028	111,095	105,297
Operations and Maintenance	26,148	24,765	70,213	75,214
Depreciation	9,426	7,464	27,707	22,154
Amortization of Regulatory Assets/(Liabilities), Net	(1,412)	1,021	(598)	634
Amortization of Rate Reduction Bonds	0	4,352	7,780	13,127
Energy Efficiency Programs	12,222	9,190	28,462	19,679
Taxes Other Than Income Taxes	7,696	5,505	20,188	15,365
Total Operating Expenses	92,877	84,325	264,847	251,470
Operating Income	28,918	28,145	96,916	81,861
Interest Expense:
Interest on Long-Term Debt	5,814	5,783	17,846	17,454
Interest on Rate Reduction Bonds	0	272	177	1,029
Other Interest	417	714	777	1,550
Total Interest Expense	6,231	6,769	18,800	20,033
Other Income/(Loss), Net	926	685	2,349	1,965
Income Before Income Tax Expense	23,613	22,061	80,465	63,793
Income Tax Expense	8,588	7,977	30,424	24,385
Net Income	$ 15,025	$ 14,084	$ 50,041	$ 39,408