CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities:
Net Income	$ 916,572	$ 1,040,519	$ 995,515
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	885,278	819,930	773,802
Deferred Income Taxes	209,812	174,812	491,630
Uncollectible Expense	63,446	61,337	44,453
Pension, SERP and PBOP Expense, Net	22,000	5,498	22,454
Pension and PBOP Contributions	(121,782)	(194,947)	(242,800)
Regulatory (Under)/Over Recoveries, Net	(124,870)	34,920	(47,935)
Amortization	195,380	252,026	89,986
Payments Related to CYAPC's DOE Pre-1983 Spent Nuclear Fuel Obligation	(29,000)	(145,000)	0
Proceeds from DOE Spent Nuclear Fuel Litigation	68,840	0	0
Impairment of Northern Pass Transmission	239,644	0	0
Other	(196,087)	(111,225)	(204,421)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(98,716)	(141,433)	(117,155)
Fuel, Materials, Supplies and REC Inventory	(8,074)	(831)	(9,223)
Taxes Receivable/Accrued, Net	(16,129)	(67,770)	52,284
Accounts Payable	14,866	24,481	56,067
Other Current Assets and Liabilities, Net	(11,603)	78,226	91,545
Net Cash Flows Provided by Operating Activities	2,009,577	1,830,543	1,996,202
Investing Activities:
Investments in Property, Plant and Equipment	(2,911,489)	(2,569,936)	(2,348,105)
Proceeds from Sales of Marketable Securities	566,592	900,749	832,903
Proceeds from Sales of Marketable Securities Used to Pay Pre-1983 Spent Nuclear Fuel Obligation	0	145,000	0
Purchases of Marketable Securities	(537,258)	(908,387)	(810,507)
Acquisition of Aquarion	0	0	(877,652)
Investments in Unconsolidated Affiliates, Net	(416,337)	(205,150)	(32,634)
Proceeds from the Sale of PSNH Generation Assets	0	193,924	0
Other Investing Activities	24,204	6,754	5,479
Net Cash Flows Used in Investing Activities	(3,274,288)	(2,437,046)	(3,230,516)
Financing Activities:
Issuance of Common Shares, Net of Issuance Costs	852,254	0	0
Cash Dividends on Common Shares	(663,239)	(640,110)	(602,083)
Cash Dividends on Preferred Stock	(7,519)	(7,519)	(7,519)
Increase/(Decrease) in Notes Payable	325,370	(379,310)	72,810
(Repayments)/Issuance of Rate Reduction Bonds	(52,332)	635,663	0
Issuance of Long-Term Debt	1,520,000	2,200,000	2,500,000
Retirement of Long-Term Debt	(801,078)	(1,050,330)	(745,000)
Other Financing Activities	(1,006)	(28,457)	(4,754)
Net Cash Flows Provided by/(Used in) Financing Activities	1,172,450	729,937	1,213,454
Net (Decrease)/Increase in Cash and Restricted Cash	(92,261)	123,434	(20,860)
Cash and Restricted Cash - Beginning of Year	209,324	85,890	106,750
Cash and Restricted Cash - End of Year	117,063	209,324	85,890
The Connecticut Light and Power Company
Operating Activities:
Net Income	410,852	377,717	376,726
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	301,188	278,557	249,352
Deferred Income Taxes	54,005	54,859	119,295
Uncollectible Expense	15,948	15,831	5,312
Pension, SERP and PBOP Expense, Net	12,761	8,943	9,909
Pension and PBOP Contributions	(24,000)	(41,150)	(2,500)
Regulatory (Under)/Over Recoveries, Net	(24,653)	(53,372)	(8,017)
Amortization of Regulatory Assets, Net	51,621	129,021	83,166
Other	(80,266)	(69,786)	(42,973)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(52,746)	(67,334)	(47,768)
Fuel, Materials, Supplies and REC Inventory	(6,171)	3,909	3,612
Taxes Receivable/Accrued, Net	(23,089)	8,954	(9,688)
Accounts Payable	102,344	(76,924)	48,032
Other Current Assets and Liabilities, Net	(11,350)	18,846	21,860
Net Cash Flows Provided by Operating Activities	726,444	588,071	806,318
Investing Activities:
Investments in Property, Plant and Equipment	(917,532)	(864,136)	(824,383)
Other Investing Activities	714	209	236
Net Cash Flows Used in Investing Activities	(916,818)	(863,927)	(824,147)
Financing Activities:
Cash Dividends on Common Shares	(341,800)	(60,000)	(254,800)
Cash Dividends on Preferred Stock	(5,559)	(5,559)	(5,559)
(Decrease)/Increase in Notes Payable to Eversource Parent	63,800	(69,500)	(10,600)
Issuance of Long-Term Debt	500,000	500,000	525,000
Retirement of Long-Term Debt	(250,000)	(300,000)	(250,000)
Capital Contributions from Eversource Parent	125,000	300,000	0
Other Financing Activities	12,291	(7,091)	15,004
Net Cash Flows Provided by/(Used in) Financing Activities	103,732	357,850	19,045
Net (Decrease)/Increase in Cash and Restricted Cash	(86,642)	81,994	1,216
Cash and Restricted Cash - Beginning of Year	91,613	9,619	8,403
Cash and Restricted Cash - End of Year	4,971	91,613	9,619
NSTAR Electric Company
Operating Activities:
Net Income	431,956	383,090	374,726
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	296,500	276,372	274,008
Deferred Income Taxes	27,107	41,438	110,499
Uncollectible Expense	25,079	22,279	21,252
Pension, SERP and PBOP Expense, Net	(12,399)	(21,521)	(9,509)
Pension and PBOP Contributions	(6,359)	(61,751)	(90,721)
Regulatory (Under)/Over Recoveries, Net	(60,863)	149,647	(20,009)
Amortization of Regulatory Assets, Net	103,735	46,654	33,831
Other	(78,220)	(65,523)	(24,872)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(11,087)	(26,403)	(50,896)
Fuel, Materials, Supplies and REC Inventory	(9,858)	(18,685)	(24,610)
Taxes Receivable/Accrued, Net	14,147	(33,900)	39,205
Accounts Payable	(22,659)	37,140	(20,421)
Other Current Assets and Liabilities, Net	1,194	51,674	26,849
Net Cash Flows Provided by Operating Activities	698,273	780,511	639,332
Investing Activities:
Investments in Property, Plant and Equipment	(861,391)	(725,766)	(719,623)
Other Investing Activities	86	58	(3,552)
Net Cash Flows Used in Investing Activities	(861,305)	(725,708)	(723,175)
Financing Activities:
Cash Dividends on Common Shares	(181,800)	(228,000)	(272,000)
Cash Dividends on Preferred Stock	(1,960)	(1,960)	(1,960)
Increase/(Decrease) in Notes Payable	(268,000)	44,500	56,500
Increase in Notes Payable to Eversource Parent	30,300	0	0
Issuance of Long-Term Debt	400,000	0	700,000
Retirement of Long-Term Debt	0	0	(400,000)
Capital Contributions from Eversource Parent	180,000	130,500	2,300
Other Financing Activities	(3,855)	108	(1,796)
Net Cash Flows Provided by/(Used in) Financing Activities	154,685	(54,852)	83,044
Net (Decrease)/Increase in Cash and Restricted Cash	(8,347)	(49)	(799)
Cash and Restricted Cash - Beginning of Year	14,659	14,708	15,507
Cash and Restricted Cash - End of Year	6,312	14,659	14,708
Public Service Company of New Hampshire
Operating Activities:
Net Income	134,048	115,876	135,996
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	93,737	92,055	128,192
Deferred Income Taxes	15,917	35,924	63,883
Uncollectible Expense	6,726	6,383	6,704
Pension, SERP and PBOP Expense, Net	417	754	1,368
Pension and PBOP Contributions	(15,400)	0	(800)
Regulatory (Under)/Over Recoveries, Net	(26,288)	(27,264)	(30,788)
Amortization of Regulatory Assets, Net	57,732	80,978	(16,577)
Other	(28,228)	(15,363)	(16,813)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(210)	(19,307)	(22,055)
Fuel, Materials, Supplies and REC Inventory	1,902	16,928	5,519
Taxes Receivable/Accrued, Net	25,374	(19,970)	339
Accounts Payable	12,281	(10,147)	29,453
Other Current Assets and Liabilities, Net	(3,573)	3,028	16,463
Net Cash Flows Provided by Operating Activities	274,435	259,875	300,884
Investing Activities:
Investments in Property, Plant and Equipment	(308,993)	(323,910)	(312,720)
Proceeds from the Sale of PSNH Generation Assets	0	193,924	0
Proceeds from the Sale of Property	0	4,782	0
Other Investing Activities	1,023	437	199
Net Cash Flows Used in Investing Activities	(307,970)	(124,767)	(312,521)
Financing Activities:
Cash Dividends on Common Shares	(271,000)	(150,000)	(23,900)
(Decrease)/Increase in Notes Payable to Eversource Parent	(30,000)	(205,900)	102,000
(Repayments)/Issuance of Rate Reduction Bonds	(52,332)	635,663	0
Return of Capital	0	(530,000)	0
Issuance of Long-Term Debt	300,000	0	0
Retirement of Long-Term Debt	(150,000)	(199,250)	(70,000)
Capital Contributions from Eversource Parent	225,000	365,000	0
Other Financing Activities	(4,168)	(89)	(225)
Net Cash Flows Provided by/(Used in) Financing Activities	17,500	(84,576)	7,875
Net (Decrease)/Increase in Cash and Restricted Cash	(16,035)	50,532	(3,762)
Cash and Restricted Cash - Beginning of Year	52,723	2,191	5,953
Cash and Restricted Cash - End of Year	$ 36,688	$ 52,723	$ 2,191