CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and Cash Equivalents	$ 40,056	$ 23,947
Receivables, Net	963,279	775,480
Unbilled Revenues	187,749	202,647
Taxes Receivable	4,527	305,359
Fuel, Materials, Supplies and Inventory	311,051	336,476
Regulatory Assets	752,378	845,843
Prepayments and Other Current Assets	155,612	129,034
Total Current Assets	2,414,652	2,618,786
Property, Plant and Equipment, Net	20,807,943	19,892,441
Deferred Debits and Other Assets:
Regulatory Assets	3,469,879	3,737,960
Goodwill	3,519,401	3,519,401
Marketable Securities	525,809	516,478
Other Long-Term Assets	344,653	295,243
Total Deferred Debits and Other Assets	7,859,742	8,069,082
Total Assets	31,082,337	30,580,309
Current Liabilities:
Notes Payable	734,500	1,160,953
Long-Term Debt - Current Portion	373,883	228,883
Accounts Payable	679,505	813,646
Obligations to Third Party Suppliers	166,845	128,564
Regulatory Liabilities	160,442	107,759
Other Current Liabilities	526,853	549,985
Total Current Liabilities	2,642,028	2,989,790
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	5,442,856	5,147,678
Regulatory Liabilities	550,162	513,595
Derivative Liabilities	427,382	337,102
Accrued Pension, SERP and PBOP	1,116,240	1,407,288
Other Long-Term Liabilities	875,589	871,499
Total Deferred Credits and Other Liabilities	8,412,229	8,277,162
Capitalization:
Long-Term Debt	9,235,128	8,805,574
Noncontrolling Interest - Preferred Stock of Subsidiaries	155,568	155,568
Common Shareholders' Equity:
Common Shares	1,669,392	1,669,313
Capital Surplus, Paid In	6,256,580	6,262,368
Retained Earnings	3,087,006	2,797,355
Accumulated Other Comprehensive Income (Loss)	(65,617)	(66,844)
Treasury Stock	(309,977)	(309,977)
Common Stockholder's Equity	10,637,384	10,352,215
Total Capitalization	20,028,080	19,313,357
Total Liabilities and Capitalization	31,082,337	30,580,309
The Connecticut Light And Power Company [Member]
Current Assets:
Cash and Cash Equivalents	8,607	1,057
Receivables, Net	425,421	352,536
Accounts Receivable from Affiliated Companies	24,012	21,214
Unbilled Revenues	87,771	99,879
Taxes Receivable	0	137,643
Regulatory Assets	267,733	268,318
Materials and Supplies	51,598	43,124
Prepaid Property Taxes	54,619	18,019
Prepayments and Other Current Assets	15,439	14,215
Total Current Assets	935,200	956,005
Property, Plant and Equipment, Net	7,453,200	7,156,809
Deferred Debits and Other Assets:
Regulatory Assets	1,398,610	1,369,028
Other Long-Term Assets	131,049	111,115
Total Deferred Debits and Other Assets	1,529,659	1,480,143
Total Assets	9,918,059	9,592,957
Current Liabilities:
Notes Payable to Eversource Parent	108,500	277,400
Long-Term Debt - Current Portion	250,000	0
Accounts Payable	228,744	267,764
Accounts Payable to Affiliated Companies	63,718	66,456
Obligations to Third Party Suppliers	66,952	60,746
Accrued Taxes	71,238	12,068
Regulatory Liabilities	75,654	61,155
Derivative Liabilities	85,342	91,820
Other Current Liabilities	94,762	98,563
Total Current Liabilities	1,044,910	935,972
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,931,369	1,820,865
Regulatory Liabilities	89,599	74,830
Derivative Liabilities	426,053	336,189
Accrued Pension, SERP and PBOP	274,456	271,056
Other Long-Term Liabilities	130,477	133,446
Total Deferred Credits and Other Liabilities	2,851,954	2,636,386
Capitalization:
Long-Term Debt	2,515,444	2,763,682
Noncontrolling Interest - Preferred Stock of Subsidiaries	116,200	116,200
Common Shareholders' Equity:
Common Shares	60,352	60,352
Capital Surplus, Paid In	2,056,402	1,910,663
Retained Earnings	1,272,962	1,170,278
Accumulated Other Comprehensive Income (Loss)	(165)	(576)
Common Stockholder's Equity	3,389,551	3,140,717
Total Capitalization	6,021,195	6,020,599
Total Liabilities and Capitalization	9,918,059	9,592,957
NSTAR Electric Company [Member]
Current Assets:
Cash and Cash Equivalents	6,154	3,346
Receivables, Net	300,692	229,936
Accounts Receivable from Affiliated Companies	8,891	4,034
Unbilled Revenues	40,370	29,464
Taxes Receivable	0	70,236
Fuel, Materials, Supplies and Inventory	44,827	75,487
Regulatory Assets	259,213	348,408
Prepayments and Other Current Assets	11,025	11,448
Total Current Assets	671,172	772,359
Property, Plant and Equipment, Net	5,875,874	5,655,458
Deferred Debits and Other Assets:
Regulatory Assets	1,043,237	1,112,977
Other Long-Term Assets	118,924	62,467
Total Deferred Debits and Other Assets	1,162,161	1,175,444
Total Assets	7,709,207	7,603,261
Current Liabilities:
Notes Payable	36,000	62,500
Long-Term Debt - Current Portion	0	200,000
Accounts Payable	194,894	228,250
Accounts Payable to Affiliated Companies	64,912	38,648
Obligations to Third Party Suppliers	87,183	56,718
Accrued Taxes	78,429	6,585
Renewable Portfolio Standards Compliance Obligations	56,741	104,847
Regulatory Liabilities	48,842	3,281
Other Current Liabilities	56,879	65,422
Total Current Liabilities	623,880	766,251
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,795,763	1,760,339
Regulatory Liabilities	357,168	264,352
Accrued Pension, SERP and PBOP	91,788	209,153
Other Long-Term Liabilities	125,137	120,939
Total Deferred Credits and Other Liabilities	2,369,856	2,354,783
Capitalization:
Long-Term Debt	2,077,955	1,829,766
Noncontrolling Interest - Preferred Stock of Subsidiaries	43,000	43,000
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	1,020,378	995,378
Retained Earnings	1,573,624	1,613,538
Accumulated Other Comprehensive Income (Loss)	514	545
Common Stockholder's Equity	2,594,516	2,609,461
Total Capitalization	4,715,471	4,482,227
Total Liabilities and Capitalization	7,709,207	7,603,261
Public Service Company Of New Hampshire [Member]
Current Assets:
Cash and Cash Equivalents	4,436	1,733
Receivables, Net	97,613	77,546
Accounts Receivable from Affiliated Companies	4,190	2,352
Unbilled Revenues	39,168	38,207
Taxes Receivable	7,913	43,128
Fuel, Materials, Supplies and Inventory	160,882	156,868
Regulatory Assets	100,598	104,971
Prepayments and Other Current Assets	4,271	24,302
Total Current Assets	419,071	449,107
Property, Plant and Equipment, Net	2,973,057	2,855,363
Deferred Debits and Other Assets:
Regulatory Assets	252,609	257,873
Other Long-Term Assets	35,793	34,176
Total Deferred Debits and Other Assets	288,402	292,049
Total Assets	3,680,530	3,596,519
Current Liabilities:
Notes Payable to Eversource Parent	107,500	231,300
Long-Term Debt - Current Portion	70,000	0
Accounts Payable	76,762	87,925
Accounts Payable to Affiliated Companies	34,350	24,214
Regulatory Liabilities	5,519	6,898
Other Current Liabilities	48,339	43,921
Total Current Liabilities	342,470	394,258
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	774,737	705,894
Regulatory Liabilities	46,428	47,851
Accrued Pension, SERP and PBOP	84,547	89,579
Other Long-Term Liabilities	50,249	50,746
Total Deferred Credits and Other Liabilities	955,961	894,070
Capitalization:
Long-Term Debt	1,001,790	1,071,017
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	843,134	748,634
Retained Earnings	542,530	494,901
Accumulated Other Comprehensive Income (Loss)	(5,355)	(6,361)
Common Stockholder's Equity	1,380,309	1,237,174
Total Capitalization	2,382,099	2,308,191
Total Liabilities and Capitalization	3,680,530	3,596,519
Western Massachusetts Electric Company [Member]
Current Assets:
Cash and Cash Equivalents	0	834
Receivables, Net	59,685	50,912
Accounts Receivable from Affiliated Companies	11,962	18,633
Unbilled Revenues	12,169	15,065
Taxes Receivable	1	33,407
Fuel, Materials, Supplies and Inventory	8,068	5,992
Regulatory Assets	54,081	56,166
Prepayments and Other Current Assets	1,374	1,890
Total Current Assets	147,340	182,899
Property, Plant and Equipment, Net	1,643,335	1,575,306
Deferred Debits and Other Assets:
Regulatory Assets	128,308	135,010
Other Long-Term Assets	28,165	24,875
Total Deferred Debits and Other Assets	156,473	159,885
Total Assets	1,947,148	1,918,090
Current Liabilities:
Notes Payable to Eversource Parent	48,200	143,400
Accounts Payable	38,191	58,364
Accounts Payable to Affiliated Companies	14,501	19,896
Obligations to Third Party Suppliers	11,444	9,654
Renewable Portfolio Standards Compliance Obligations	16,314	6,395
Regulatory Liabilities	12,384	13,122
Other Current Liabilities	12,258	13,878
Total Current Liabilities	153,292	264,709
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	486,137	470,539
Regulatory Liabilities	14,422	11,597
Accrued Pension, SERP and PBOP	16,032	19,515
Other Long-Term Liabilities	42,072	36,819
Total Deferred Credits and Other Liabilities	558,663	538,470
Capitalization:
Long-Term Debt	566,657	517,329
Common Shareholders' Equity:
Common Shares	10,866	10,866
Capital Surplus, Paid In	444,399	391,398
Retained Earnings	215,743	198,140
Accumulated Other Comprehensive Income (Loss)	(2,472)	(2,822)
Common Stockholder's Equity	668,536	597,582
Total Capitalization	1,235,193	1,114,911
Total Liabilities and Capitalization	$ 1,947,148	$ 1,918,090