CONSOLIDATED STATEMENT OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Operating Activities:
Net Income	$ 255,133us-gaap_NetIncomeLoss	$ 237,836us-gaap_NetIncomeLoss
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	163,837us-gaap_Depreciation	150,807us-gaap_Depreciation
Deferred Income Tax Expense (Benefit)	148,193us-gaap_DeferredIncomeTaxExpenseBenefit	137,417us-gaap_DeferredIncomeTaxExpenseBenefit
Pension, SERP and PBOP Expense	26,495	24,995
Pension and PBOP Contributions	(26,659)	(6,622)
Regulatory Over/(Under) Recoveries, Net	(110,748)	872
Amortization of Regulatory Assets/(Liabilities), Net	60,604us-gaap_AmortizationOfRegulatoryAsset	57,898us-gaap_AmortizationOfRegulatoryAsset
Proceeds from DOE Damages Claim, Net	0es_ProceedsFromDoeDamagesClaimNet	163,300es_ProceedsFromDoeDamagesClaimNet
Other Noncash Income (Expense)	(21,617)us-gaap_OtherNoncashIncomeExpense	(7,574)us-gaap_OtherNoncashIncomeExpense
CYAPC and YAEC Deferred DOE Proceeds		(163,300)es_CYAPCandYAECDeferredDOEProceeds
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(328,299)us-gaap_IncreaseDecreaseInReceivables	(182,221)us-gaap_IncreaseDecreaseInReceivables
Increase Decrease in Fuel, Materials and Supplies	68,172us-gaap_IncreaseDecreaseInInventories	75,041us-gaap_IncreaseDecreaseInInventories
Taxes Receivable/(Accrued)	272,021	(59,840)
Accounts Payable	(59,496)	53,905
Other Current Assets and Liabilities	34,179	11,282
Net Cash Flows Provided by Operating Activities	481,815	493,796
Investing Activities:
Investments in Property, Plant and Equipment	(362,586)	(348,691)
Proceeds from Sales of Marketable Securities	114,730	128,505
Purchases of Marketable Securities	(116,735)	(132,605)
Other Investing Activities	66	1,637
Net Cash Flows Used in Investing Activities	(364,525)	(351,154)
Financing Activities:
Cash Dividends on Common Stock	(132,433)us-gaap_PaymentsOfDividendsCommonStock	(118,460)us-gaap_PaymentsOfDividendsCommonStock
Cash Dividends on Preferred Stock	(1,879)	(1,879)
Increase/(Decrease) in Short-Term Debt	(399,575)	(299,500)
Issuance of Long-Term Debt	450,000	400,000
Retirements of Long-Term Debt	0us-gaap_RepaymentsOfLongTermDebt	(75,000)us-gaap_RepaymentsOfLongTermDebt
Other Financing Activities	(1,079)	(2,017)
Net Cash Flows Provided by/(Used in) Financing Activities	(84,966)	(96,856)
Net Increase/(Decrease) in Cash	32,324	45,786
Cash - Beginning of Year	38,703us-gaap_Cash	43,364us-gaap_Cash
Cash - End of Year	71,027us-gaap_Cash	89,150us-gaap_Cash
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	69,234	79,299
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	52,902	46,130
Deferred Income Tax Expense (Benefit)	19,340	59,334
Pension, SERP and PBOP Expense, Net of Contributions	3,883	4,086
Regulatory Over/(Under) Recoveries, Net	(67,393)	(40,399)
Amortization of Regulatory Assets/(Liabilities), Net	48,306	29,931
Other Noncash Income (Expense)	2,322	4,536
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(124,969)	(82,833)
Taxes Receivable/(Accrued)	158,163	7,015
Accounts Payable	(20,194)	(2,872)
Other Current Assets and Liabilities	(7,727)	(8,730)
Net Cash Flows Provided by Operating Activities	133,867	95,497
Investing Activities:
Investments in Property, Plant and Equipment	(127,631)	(107,993)
Other Investing Activities	1,981	1,027
Net Cash Flows Used in Investing Activities	(125,650)	(106,966)
Financing Activities:
Cash Dividends on Common Stock	(49,000)	(42,800)
Cash Dividends on Preferred Stock	(1,390)	(1,390)
Increase/(Decrease) in Notes Payable to Affiliate	56,700	64,300
Other Financing Activities	(65)	(203)
Net Cash Flows Provided by/(Used in) Financing Activities	6,245	19,907
Net Increase/(Decrease) in Cash	14,462	8,438
Cash - Beginning of Year	2,356	7,237
Cash - End of Year	16,818	15,675
NSTAR Electric Company [Member]
Operating Activities:
Net Income	83,561	58,087
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Bad Debt Expense	8,049	6,096
Depreciation	48,768	46,626
Deferred Income Tax Expense (Benefit)	41,297	1,585
Pension, SERP and PBOP Expense, Net of Contributions	1,164	(4,908)
Regulatory Over/(Under) Recoveries, Net	(103,142)	6,423
Amortization of Regulatory Assets/(Liabilities), Net	(5,565)	15,664
Other Noncash Income (Expense)	(21,885)	(15,538)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(90,465)	(14,348)
Increase Decrease in Fuel, Materials and Supplies	(13,504)	(3,606)
Taxes Receivable/(Accrued)	96,319	21,504
Accounts Payable	29,210	86,309
Other Current Assets and Liabilities	51,157	31,112
Accounts Payable Related Parties	96,368	(43,654)
Net Cash Flows Provided by Operating Activities	221,332	191,352
Investing Activities:
Investments in Property, Plant and Equipment	(79,776)	(94,957)
Other Investing Activities	53	(489)
Net Cash Flows Used in Investing Activities	(79,723)	(95,446)
Financing Activities:
Cash Dividends on Common Stock	(49,500)	(253,000)
Cash Dividends on Preferred Stock	(490)	(490)
Increase/(Decrease) in Short-Term Debt	(86,500)	(103,500)
Issuance of Long-Term Debt	0	300,000
Other Financing Activities	5	(4,902)
Net Cash Flows Provided by/(Used in) Financing Activities	(136,485)	(61,892)
Net Increase/(Decrease) in Cash	5,124	34,014
Cash - Beginning of Year	12,773	8,021
Cash - End of Year	17,897	42,035
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	32,045	32,638
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	25,646	24,215
Deferred Income Tax Expense (Benefit)	38,767	33,667
Regulatory Over/(Under) Recoveries, Net	(288)	6,827
Amortization of Regulatory Assets/(Liabilities), Net	15,132	12,562
Other Noncash Income (Expense)	2,999	4,660
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(31,556)	(14,268)
Increase Decrease in Fuel, Materials and Supplies	34,572	34,326
Taxes Receivable/(Accrued)	(16,576)	(30,254)
Accounts Payable	(4,285)	3,403
Other Current Assets and Liabilities	17,468	21,505
Net Cash Flows Provided by Operating Activities	113,924	129,281
Investing Activities:
Investments in Property, Plant and Equipment	(71,905)	(61,864)
Other Investing Activities	(2,277)	(76)
Net Cash Flows Used in Investing Activities	(74,182)	(61,940)
Financing Activities:
Cash Dividends on Common Stock	(26,500)	(16,500)
Increase/(Decrease) in Notes Payable to Affiliate	(8,500)	(46,600)
Other Financing Activities	(82)	(87)
Net Cash Flows Provided by/(Used in) Financing Activities	(35,082)	(63,187)
Net Increase/(Decrease) in Cash	4,660	4,154
Cash - Beginning of Year	489	130
Cash - End of Year	5,149	4,284
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	13,244	18,102
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	10,375	10,321
Deferred Income Tax Expense (Benefit)	12,759	14,688
Regulatory Over/(Under) Recoveries, Net	(14,442)	5,780
Amortization of Regulatory Assets/(Liabilities), Net	3,927	399
Other Noncash Income (Expense)	(1,197)	(1,351)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(26,298)	34,905
Taxes Receivable/(Accrued)	64	(17,126)
Accounts Payable	85	(10,516)
Other Current Assets and Liabilities	65	(8,869)
Net Cash Flows Provided by Operating Activities	(1,418)	46,333
Investing Activities:
Investments in Property, Plant and Equipment	(35,899)	(30,347)
Proceeds from Sales of Marketable Securities	23,249	34,656
Purchases of Marketable Securities	(23,442)	(34,804)
Net Cash Flows Used in Investing Activities	(36,092)	(30,495)
Financing Activities:
Cash Dividends on Common Stock	(9,300)	(49,000)
Increase/(Decrease) in Notes Payable to Affiliate	49,100	37,400
Other Financing Activities	(245)	(11)
Net Cash Flows Provided by/(Used in) Financing Activities	39,555	(11,611)
Net Increase/(Decrease) in Cash	2,045	4,227
Cash - Beginning of Year	0	0
Cash - End of Year	$ 2,045	$ 4,227

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The net cash outflow or inflow from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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Cash outflow for purchase of trading, available-for-sale securities and held-to-maturity securities.

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