CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities:
Net Income	$ 451,562	$ 464,520
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	350,492	327,505
Deferred Income Tax Expense (Benefit)	250,851	176,800
Pension, SERP and PBOP Expense	22,659	48,432
Pension and PBOP Contributions	(65,929)	(31,032)
Regulatory Over/(Under) Recoveries, Net	(5,768)	(73,547)
Amortization of Regulatory Assets/(Liabilities), Net	12,281	59,438
Other	(10,808)	(38,521)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(76,751)	(123,984)
Increase Decrease in Fuel, Materials and Supplies	43,930	60,044
Taxes Receivable/(Accrued)	230,075	214,577
Accounts Payable	(151,996)	(228,176)
Other Current Assets and Liabilities, Net	(72,160)	9,226
Net Cash Flows Provided by Operating Activities	978,438	865,282
Investing Activities:
Investments in Property, Plant and Equipment	(869,168)	(740,379)
Proceeds from Sales of Marketable Securities	327,581	427,990
Purchases of Marketable Securities	(322,244)	(408,242)
Other Investing Activities	(2,991)	4,821
Net Cash Flows Used in Investing Activities	(866,822)	(715,810)
Financing Activities:
Cash Dividends on Common Stock	(282,314)	(264,936)
Cash Dividends on Preferred Stock	(3,759)	(3,759)
Increase/(Decrease) in Short-Term Debt	(393,953)	(449,375)
Issuance of Long-Term Debt	800,000	750,000
Retirements of Long-Term Debt	(200,000)	(166,577)
Other Financing Activities	(16,811)	(17,059)
Net Cash Flows Provided by/(Used in) Financing Activities	(96,837)	(151,706)
Net Increase/(Decrease) in Cash	14,779	(2,234)
Cash - Beginning of Year	23,947	38,703
Cash - End of Year	38,726	36,469
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	169,921	148,004
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	114,500	105,094
Deferred Income Tax Expense (Benefit)	97,913	30,145
Pension, SERP and PBOP Expense, Net of Contributions	3,325	7,079
Regulatory Over/(Under) Recoveries, Net	(40,386)	(55,302)
Amortization of Regulatory Assets/(Liabilities), Net	6,891	40,776
Other	(4,477)	(2,432)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(26,729)	(73,279)
Taxes Receivable/(Accrued)	145,852	123,051
Accounts Payable	(38,137)	(55,192)
Other Current Assets and Liabilities, Net	774	2,085
Net Cash Flows Provided by Operating Activities	429,447	270,029
Investing Activities:
Investments in Property, Plant and Equipment	(288,630)	(242,346)
Proceeds From Sale Of Property Plant And Equipment	9,047
Other Investing Activities	205	(1,362)
Net Cash Flows Used in Investing Activities	(279,378)	(243,708)
Financing Activities:
Cash Dividends on Common Stock	(99,800)	(98,000)
Cash Dividends on Preferred Stock	(2,779)	(2,779)
Issuance of Long-Term Debt		300,000
Increase/(Decrease) in Notes Payable to Affiliate	(184,400)	(47,800)
Retirements of Long-Term Debt		(162,000)
Capital Contributions from NU Parent	145,700
Other Financing Activities	(398)	(8,871)
Net Cash Flows Provided by/(Used in) Financing Activities	(141,677)	(19,450)
Net Increase/(Decrease) in Cash	8,392	6,871
Cash - Beginning of Year	1,057	2,356
Cash - End of Year	9,449	9,227
NSTAR Electric Company [Member]
Operating Activities:
Net Income	122,661	165,523
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	104,457	97,716
Deferred Income Tax Expense (Benefit)	48,505	61,734
Pension, SERP and PBOP Expense, Net of Contributions	(13,236)	(264)
Regulatory Over/(Under) Recoveries, Net	26,277	(96,290)
Amortization of Regulatory Assets/(Liabilities), Net	8,654	(12,901)
Other	(3,978)	(28,653)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(56,140)	(91,753)
Increase Decrease in Fuel, Materials and Supplies	35,194	17,595
Taxes Receivable/(Accrued)	45,608	100,661
Accounts Payable	(88,774)	(30,839)
Other Current Assets and Liabilities, Net	(64,084)	25,076
Net Cash Flows Provided by Operating Activities	165,144	207,605
Investing Activities:
Investments in Property, Plant and Equipment	(199,824)	(188,103)
Other Investing Activities		53
Net Cash Flows Used in Investing Activities	(199,824)	(188,050)
Financing Activities:
Cash Dividends on Common Stock	(278,300)	(99,000)
Cash Dividends on Preferred Stock	(980)	(980)
Increase/(Decrease) in Short-Term Debt	266,500	75,200
Issuance of Long-Term Debt	250,000
Retirements of Long-Term Debt	(200,000)	(4,700)
Other Financing Activities	(2,495)	0
Net Cash Flows Provided by/(Used in) Financing Activities	34,725	(29,480)
Net Increase/(Decrease) in Cash	45	(9,925)
Cash - Beginning of Year	3,346	12,773
Cash - End of Year	3,391	2,848
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	67,313	59,990
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	56,879	51,397
Deferred Income Tax Expense (Benefit)	45,976	47,454
Regulatory Over/(Under) Recoveries, Net	(10,740)	(3,089)
Amortization of Regulatory Assets/(Liabilities), Net	332	27,181
Other	(8,484)	8,726
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(5,247)	(6,597)
Increase Decrease in Fuel, Materials and Supplies	5,394	11,019
Taxes Receivable/(Accrued)	33,840	(20,414)
Accounts Payable	20,417	(21,362)
Other Current Assets and Liabilities, Net	(1,422)	(3,792)
Net Cash Flows Provided by Operating Activities	204,258	150,513
Investing Activities:
Investments in Property, Plant and Equipment	(138,713)	(140,171)
Other Investing Activities	172	169
Net Cash Flows Used in Investing Activities	(138,541)	(140,002)
Financing Activities:
Cash Dividends on Common Stock	(38,800)	(53,000)
Increase/(Decrease) in Notes Payable to Affiliate	(110,400)	43,000
Capital Contributions from NU Parent	83,000
Other Financing Activities	(166)	(182)
Net Cash Flows Provided by/(Used in) Financing Activities	(66,366)	(10,182)
Net Increase/(Decrease) in Cash	(649)	329
Cash - Beginning of Year	1,733	489
Cash - End of Year	1,084	818
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	30,092	27,439
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	22,847	21,223
Deferred Income Tax Expense (Benefit)	17,155	12,503
Regulatory Over/(Under) Recoveries, Net	(2,651)	(7,911)
Amortization of Regulatory Assets/(Liabilities), Net	2,203	7,264
Other	(2,547)	(3,598)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	6,500	(11,593)
Taxes Receivable/(Accrued)	32,985	18,774
Accounts Payable	(13,176)	(21,056)
Other Current Assets and Liabilities, Net	2,502	859
Net Cash Flows Provided by Operating Activities	95,910	43,904
Investing Activities:
Investments in Property, Plant and Equipment	(71,459)	(62,966)
Proceeds from Sales of Marketable Securities	1,484	49,739
Purchases of Marketable Securities	(1,457)	(50,118)
Net Cash Flows Used in Investing Activities	(71,432)	(63,345)
Financing Activities:
Cash Dividends on Common Stock	(19,000)	(18,600)
Issuance of Long-Term Debt	50,000
Increase/(Decrease) in Notes Payable to Affiliate	(89,700)	39,200
Capital Contributions from NU Parent	35,000
Other Financing Activities	(191)	(16)
Net Cash Flows Provided by/(Used in) Financing Activities	(23,891)	20,584
Net Increase/(Decrease) in Cash	587	1,143
Cash - Beginning of Year	834	0
Cash - End of Year	$ 1,421	$ 1,143