CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities:
Net Income	$ 718,762	$ 702,319
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	531,781	495,389
Deferred Income Taxes	301,413	153,353
Pension, SERP and PBOP Expense	31,627	71,802
Pension and PBOP Contributions	(121,854)	(162,880)
Regulatory Over/(Under) Recoveries, Net	152,808	31,874
Amortization of Regulatory Assets/(Liabilities), Net	56,223	42,587
Other	(27,671)	(39,822)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(191,454)	(148,442)
Fuel, Materials, Supplies and Inventory	25,425	47,380
Taxes Receivable/Accrued, Net	347,898	383,047
Accounts Payable	(121,513)	(233,660)
Other Current Assets and Liabilities, Net	(53,077)	8,370
Net Cash Flows Provided by Operating Activities	1,650,368	1,351,317
Investing Activities:
Investments in Property, Plant and Equipment	(1,359,171)	(1,177,285)
Proceeds from Sales of Marketable Securities	444,209	556,582
Purchases of Marketable Securities	(437,197)	(535,044)
Other Investing Activities	(9,463)	(2,769)
Net Cash Flows Used in Investing Activities	(1,361,622)	(1,158,516)
Financing Activities:
Cash Dividends on Common Shares	(423,471)	(397,363)
Cash Dividends on Preferred Stock	(5,639)	(5,639)
Decrease in Notes Payable	(426,453)	(387,575)
Issuance of Long-Term Debt	800,000	825,000
Retirements of Long-Term Debt	(200,000)	(216,700)
Other Financing Activities	(17,074)	(13,446)
Net Cash Flows Used in Financing Activities	(272,637)	(195,723)
Net Increase/(Decrease) in Cash and Cash Equivalents	16,109	(2,922)
Cash and Cash Equivalents - Beginning of Period	23,947	38,703
Cash and Cash Equivalents - End of Period	40,056	35,781
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	256,553	228,192
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	172,175	159,903
Deferred Income Taxes	109,637	(11,011)
Pension and PBOP Contributions, Net of Pension, SERP and PBOP Expense	4,825	10,654
Regulatory Over/(Under) Recoveries, Net	33,492	12,504
Amortization of Regulatory Assets/(Liabilities), Net	30,308	17,917
Other	(14,873)	(13,048)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(100,074)	(91,842)
Taxes Receivable/Accrued, Net	197,422	160,031
Accounts Payable	(30,168)	(20,485)
Other Current Assets and Liabilities, Net	(44,908)	(31,044)
Net Cash Flows Provided by Operating Activities	614,389	421,771
Investing Activities:
Investments in Property, Plant and Equipment	(438,518)	(359,339)
Proceeds from the Sale of Property, Plant and Equipment	9,047	0
Other Investing Activities	310	(740)
Net Cash Flows Used in Investing Activities	(429,161)	(360,079)
Financing Activities:
Cash Dividends on Common Shares	(149,700)	(147,000)
Cash Dividends on Preferred Stock	(4,169)	(4,169)
(Decrease)/Increase in Notes Payable to Eversource Parent	(168,900)	(133,400)
Issuance of Long-Term Debt	0	300,000
Retirements of Long-Term Debt	0	(162,000)
Capital Contributions from Eversource Parent	145,700	105,000
Other Financing Activities	(609)	(9,072)
Net Cash Flows Used in Financing Activities	(177,678)	(50,641)
Net Increase/(Decrease) in Cash and Cash Equivalents	7,550	11,051
Cash and Cash Equivalents - Beginning of Period	1,057	2,356
Cash and Cash Equivalents - End of Period	8,607	13,407
NSTAR Electric Company [Member]
Operating Activities:
Net Income	239,857	284,148
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	159,151	146,818
Deferred Income Taxes	40,960	54,188
Pension and PBOP Contributions, Net of Pension, SERP and PBOP Expense	(25,364)	(1,138)
Regulatory Over/(Under) Recoveries, Net	131,774	(48,903)
Amortization of Regulatory Assets/(Liabilities), Net	18,275	(10,643)
Other	(20,088)	(34,223)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(103,444)	(84,587)
Fuel, Materials, Supplies and Inventory	30,659	21,863
Taxes Receivable/Accrued, Net	141,379	207,516
Accounts Payable	(22,913)	(79,449)
Other Current Assets and Liabilities, Net	(25,942)	46,671
Net Cash Flows Provided by Operating Activities	564,304	502,261
Investing Activities:
Investments in Property, Plant and Equipment	(327,731)	(314,055)
Net Cash Flows Used in Investing Activities	(327,731)	(314,055)
Financing Activities:
Cash Dividends on Common Shares	(278,300)	(148,500)
Cash Dividends on Preferred Stock	(1,470)	(1,470)
Decrease in Notes Payable	(26,500)	(43,500)
Issuance of Long-Term Debt	250,000	0
Retirements of Long-Term Debt	(200,000)	(4,700)
Capital Contributions from Eversource Parent	25,000	0
Other Financing Activities	(2,495)	0
Net Cash Flows Used in Financing Activities	(233,765)	(198,170)
Net Increase/(Decrease) in Cash and Cash Equivalents	2,808	(9,964)
Cash and Cash Equivalents - Beginning of Period	3,346	12,773
Cash and Cash Equivalents - End of Period	6,154	2,809
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	105,829	92,491
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	86,524	77,989
Deferred Income Taxes	74,522	42,563
Regulatory Over/(Under) Recoveries, Net	(4,289)	2,639
Amortization of Regulatory Assets/(Liabilities), Net	14,490	29,148
Other	(12,660)	10,894
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(28,754)	(25,126)
Fuel, Materials, Supplies and Inventory	(4,014)	4,156
Taxes Receivable/Accrued, Net	33,589	9,026
Accounts Payable	14,508	(20,058)
Other Current Assets and Liabilities, Net	26,207	20,141
Net Cash Flows Provided by Operating Activities	305,952	243,863
Investing Activities:
Investments in Property, Plant and Equipment	(215,804)	(209,522)
Other Investing Activities	272	241
Net Cash Flows Used in Investing Activities	(215,532)	(209,281)
Financing Activities:
Cash Dividends on Common Shares	(58,200)	(79,500)
(Decrease)/Increase in Notes Payable to Eversource Parent	(123,800)	46,800
Capital Contributions from Eversource Parent	94,500	0
Other Financing Activities	(217)	(268)
Net Cash Flows Used in Financing Activities	(87,717)	(32,968)
Net Increase/(Decrease) in Cash and Cash Equivalents	2,703	1,614
Cash and Cash Equivalents - Beginning of Period	1,733	489
Cash and Cash Equivalents - End of Period	4,436	2,103
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	46,103	42,410
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	34,414	32,420
Deferred Income Taxes	15,587	5,531
Regulatory Over/(Under) Recoveries, Net	323	4,024
Amortization of Regulatory Assets/(Liabilities), Net	3,305	11,194
Other	(2,532)	(4,500)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	1,933	(32,664)
Taxes Receivable/Accrued, Net	36,658	24,064
Accounts Payable	(16,240)	(14,018)
Other Current Assets and Liabilities, Net	5,277	(463)
Net Cash Flows Provided by Operating Activities	124,828	67,998
Investing Activities:
Investments in Property, Plant and Equipment	(104,811)	(93,705)
Proceeds from Sales of Marketable Securities	1,934	71,110
Purchases of Marketable Securities	(1,894)	(71,625)
Net Cash Flows Used in Investing Activities	(104,771)	(94,220)
Financing Activities:
Cash Dividends on Common Shares	(28,500)	(27,900)
(Decrease)/Increase in Notes Payable to Eversource Parent	(95,200)	104,800
Issuance/(Retirement) of Long-Term Debt	50,000	(50,000)
Capital Contributions from Eversource Parent	53,000	0
Other Financing Activities	(191)	(20)
Net Cash Flows Used in Financing Activities	(20,891)	26,880
Net Increase/(Decrease) in Cash and Cash Equivalents	(834)	658
Cash and Cash Equivalents - Beginning of Period	834	0
Cash and Cash Equivalents - End of Period	$ 0	$ 658