Public Service Co Of New Hampshire 10-Q 7 Nov 19 2019 Q3 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Document And Entity [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Fiscal Period Focus	Q3
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity Registrant Name	EVERSOURCE ENERGY
Entity Incorporation, State or Country Code	MA
Entity Central Index Key	0000072741
Entity Address, Address Line One	300 Cadwell Drive
Entity Address, City or Town	Springfield
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01104
City Area Code	800
Local Phone Number	286-5000
Entity File Number	1-5324
Entity Tax Identification Number	04-2147929
Title of 12(b) Security	Common Shares, $5.00 par value per share
Trading Symbol	ES
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		323,761,393
The Connecticut Light and Power Company
Document And Entity [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	THE CONNECTICUT LIGHT AND POWER COMPANY
Entity Incorporation, State or Country Code	CT
Entity Central Index Key	0000023426
Entity Address, Address Line One	107 Selden Street
Entity Address, City or Town	Berlin
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06037-1616
City Area Code	800
Local Phone Number	286-5000
Entity File Number	0-00404
Entity Tax Identification Number	06-0303850
Entity Filer Category	Non-accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		6,035,205
NSTAR Electric Company
Document And Entity [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	NSTAR ELECTRIC COMPANY
Entity Incorporation, State or Country Code	MA
Entity Central Index Key	0000013372
Entity Address, Address Line One	800 Boylston Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02199
City Area Code	800
Local Phone Number	286-5000
Entity File Number	1-02301
Entity Tax Identification Number	04-1278810
Entity Filer Category	Non-accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		200
Public Service Company of New Hampshire
Document And Entity [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE
Entity Incorporation, State or Country Code	NH
Entity Central Index Key	0000315256
Entity Address, Address Line One	Energy Park
Entity Address, Address Line Two	780 North Commercial Street
Entity Address, City or Town	Manchester
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03101-1134
City Area Code	800
Local Phone Number	286-5000
Entity File Number	1-6392
Entity Tax Identification Number	02-0181050
Entity Filer Category	Non-accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		301

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current Assets:
Cash	$ 22,688	$ 108,068
Receivables, Net	993,396	994,055
Unbilled Revenues	150,394	176,285
Fuel, Materials, Supplies and REC Inventory	204,012	238,042
Regulatory Assets	538,162	514,779
Prepayments and Other Current Assets	312,253	260,995
Total Current Assets	2,220,905	2,292,224
Property, Plant and Equipment, Net	26,911,877	25,610,428
Deferred Debits and Other Assets:
Regulatory Assets	4,292,560	4,631,137
Goodwill	4,427,266	4,427,266
Investments in Unconsolidated Affiliates	861,687	464,286
Marketable Securities	404,804	417,508
Other Long-Term Assets	606,295	398,407
Total Deferred Debits and Other Assets	10,592,612	10,338,604
Total Assets	39,725,394	38,241,256
Current Liabilities:
Notes Payable	712,500	910,000
Long-Term Debt – Current Portion	853,066	837,319
Rate Reduction Bonds – Current Portion	43,210	52,332
Accounts Payable	892,106	1,119,995
Regulatory Liabilities	441,189	370,230
Other Current Liabilities	806,839	823,006
Total Current Liabilities	3,748,910	4,112,882
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	3,604,791	3,506,030
Regulatory Liabilities	3,644,477	3,609,475
Derivative Liabilities	357,869	379,562
Accrued Pension, SERP and PBOP	821,172	962,510
Other Long-Term Liabilities	1,290,704	1,196,336
Total Deferred Credits and Other Liabilities	9,719,013	9,653,913
Long-Term Debt	13,440,165	12,248,743
Rate Reduction Bonds	540,122	583,331
Noncontrolling Interest – Preferred Stock of Subsidiaries	155,570	155,570
Common Shareholders' Equity:
Common Shares	1,699,292	1,669,392
Capital Surplus, Paid In	6,675,889	6,241,222
Retained Earnings	4,100,220	3,953,974
Accumulated Other Comprehensive Income (Loss)	(52,017)	(60,000)
Treasury Stock	(301,770)	(317,771)
Common Shareholders' Equity	12,121,614	11,486,817
Commitments and Contingencies (Note 9)
Total Liabilities and Capitalization	39,725,394	38,241,256
The Connecticut Light and Power Company
Current Assets:
Cash	9,286	87,721
Receivables, Net	428,050	397,026
Accounts Receivable from Affiliated Companies	34,702	23,082
Unbilled Revenues	48,211	56,971
Fuel, Materials, Supplies and REC Inventory	52,209	44,529
Regulatory Assets	173,339	125,155
Prepaid Property Taxes	66,510	19,555
Prepayments and Other Current Assets	24,236	40,724
Total Current Assets	836,543	794,763
Property, Plant and Equipment, Net	9,456,562	8,909,701
Deferred Debits and Other Assets:
Regulatory Assets	1,404,502	1,505,488
Other Long-Term Assets	229,092	199,767
Total Deferred Debits and Other Assets	1,633,594	1,705,255
Total Assets	11,926,699	11,409,719
Current Liabilities:
Notes Payable to Eversource Parent	173,100	0
Long-Term Debt – Current Portion	0	250,000
Accounts Payable	280,463	324,983
Accounts Payable to Affiliated Companies	76,916	26,452
Obligations to Third Party Suppliers	57,823	56,248
Regulatory Liabilities	168,053	109,614
Derivative Liabilities	64,572	55,058
Other Current Liabilities	169,600	161,088
Total Current Liabilities	990,527	983,443
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,205,687	1,166,784
Regulatory Liabilities	1,159,909	1,122,157
Derivative Liabilities	357,728	379,536
Accrued Pension, SERP and PBOP	248,557	282,771
Other Long-Term Liabilities	149,293	155,495
Total Deferred Credits and Other Liabilities	3,121,174	3,106,743
Long-Term Debt	3,518,464	3,004,016
Noncontrolling Interest – Preferred Stock of Subsidiaries	116,200	116,200
Common Shareholders' Equity:
Common Shares	60,352	60,352
Capital Surplus, Paid In	2,410,765	2,410,765
Retained Earnings	1,708,892	1,727,899
Accumulated Other Comprehensive Income (Loss)	325	301
Common Shareholders' Equity	4,180,334	4,199,317
Commitments and Contingencies (Note 9)
Total Liabilities and Capitalization	11,926,699	11,409,719
NSTAR Electric Company
Current Assets:
Cash	264	1,606
Receivables, Net	385,689	361,296
Accounts Receivable from Affiliated Companies	39,386	31,344
Unbilled Revenues	42,794	34,518
Fuel, Materials, Supplies and REC Inventory	90,169	114,202
Regulatory Assets	201,215	241,747
Prepayments and Other Current Assets	11,564	51,960
Total Current Assets	771,081	836,673
Property, Plant and Equipment, Net	9,264,180	8,794,700
Deferred Debits and Other Assets:
Regulatory Assets	1,159,056	1,196,512
Prepaid PBOP	152,978	132,810
Other Long-Term Assets	149,785	109,764
Total Deferred Debits and Other Assets	1,461,819	1,439,086
Total Assets	11,497,080	11,070,459
Current Liabilities:
Notes Payable	28,000	278,500
Notes Payable to Eversource Parent	48,700	0
Long-Term Debt – Current Portion	95,000	0
Accounts Payable	304,346	384,398
Accounts Payable to Affiliated Companies	84,898	89,636
Obligations to Third Party Suppliers	110,243	109,547
Renewable Portfolio Standards Compliance Obligations	113,330	139,898
Regulatory Liabilities	199,381	190,620
Other Current Liabilities	112,577	74,872
Total Current Liabilities	1,096,475	1,267,471
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,329,266	1,294,467
Regulatory Liabilities	1,519,631	1,513,279
Accrued Pension, SERP and PBOP	20,544	14,145
Other Long-Term Liabilities	325,617	263,096
Total Deferred Credits and Other Liabilities	3,195,058	3,084,987
Long-Term Debt	3,246,631	2,944,846
Noncontrolling Interest – Preferred Stock of Subsidiaries	43,000	43,000
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	1,663,442	1,633,442
Retained Earnings	2,253,509	2,098,091
Accumulated Other Comprehensive Income (Loss)	(1,035)	(1,378)
Common Shareholders' Equity	3,915,916	3,730,155
Commitments and Contingencies (Note 9)
Total Liabilities and Capitalization	11,497,080	11,070,459
Public Service Company of New Hampshire
Current Assets:
Cash	1,647	1,439
Receivables, Net	107,096	104,854
Accounts Receivable from Affiliated Companies	23,882	8,444
Unbilled Revenues	38,901	47,145
Taxes Receivable	1,111	25,913
Fuel, Materials, Supplies and REC Inventory	23,960	37,504
Regulatory Assets	78,097	67,228
Special Deposits	18,526	47,498
Prepayments and Other Current Assets	2,726	17,564
Total Current Assets	295,946	357,589
Property, Plant and Equipment, Net	3,031,985	2,880,073
Deferred Debits and Other Assets:
Regulatory Assets	792,332	862,288
Other Long-Term Assets	40,890	27,406
Total Deferred Debits and Other Assets	833,222	889,694
Total Assets	4,161,153	4,127,356
Current Liabilities:
Notes Payable to Eversource Parent	42,100	57,000
Long-Term Debt – Current Portion	150,000	150,000
Rate Reduction Bonds – Current Portion	43,210	52,332
Accounts Payable	89,992	111,292
Accounts Payable to Affiliated Companies	35,940	26,029
Regulatory Liabilities	54,681	55,526
Other Current Liabilities	61,260	64,046
Total Current Liabilities	477,183	516,225
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	500,391	481,221
Regulatory Liabilities	418,106	428,069
Accrued Pension, SERP and PBOP	88,492	124,457
Other Long-Term Liabilities	33,454	36,339
Total Deferred Credits and Other Liabilities	1,040,443	1,070,086
Long-Term Debt	951,471	655,173
Rate Reduction Bonds	540,122	583,331
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	678,134	678,134
Retained Earnings	475,770	627,258
Accumulated Other Comprehensive Income (Loss)	(1,970)	(2,851)
Common Shareholders' Equity	1,151,934	1,302,541
Commitments and Contingencies (Note 9)
Total Liabilities and Capitalization	$ 4,161,153	$ 4,127,356

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Revenues	$ 2,175,797	$ 2,271,425	$ 6,476,084	$ 6,413,243
Operating Expenses:
Purchased Power, Fuel and Transmission	730,255	842,291	2,326,041	2,442,953
Operations and Maintenance	331,054	344,475	994,660	970,881
Depreciation	222,599	208,671	656,632	612,077
Amortization	73,854	92,711	183,760	174,108
Energy Efficiency Programs	136,832	129,965	382,785	366,162
Taxes Other Than Income Taxes	171,965	187,291	537,636	547,155
Impairment of Northern Pass Transmission	0	0	239,644	0
Total Operating Expenses	1,666,559	1,805,404	5,321,158	5,113,336
Operating Income/(Loss)	509,238	466,021	1,154,926	1,299,907
Interest Expense	135,216	125,201	399,654	372,734
Other Income, Net	26,968	16,718	103,818	100,656
Income Before Income Tax Expense	400,990	357,538	859,090	1,027,829
Income Tax Expense	80,226	66,278	194,435	220,497
Net Income	320,764	291,260	664,655	807,332
Net Income Attributable to Noncontrolling Interests	1,880	1,880	5,639	5,639
Net Income Attributable to Common Shareholders	$ 318,884	$ 289,380	$ 659,016	$ 801,693
Basic Earnings Per Common Share (in dollars per share)	$ 0.98	$ 0.91	$ 2.06	$ 2.53
Diluted Earnings Per Common Share (in dollars per share)	$ 0.98	$ 0.91	$ 2.05	$ 2.52
Weighted Average Common Shares Outstanding:
Basic (in shares)	324,037,169	317,360,110	320,442,253	317,367,252
Diluted (in shares)	326,008,342	317,967,311	321,570,926	317,948,498
The Connecticut Light and Power Company
Operating Revenues	$ 853,943	$ 865,028	$ 2,444,034	$ 2,344,903
Operating Expenses:
Purchased Power, Fuel and Transmission	299,017	314,571	865,389	850,794
Operations and Maintenance	135,077	128,523	399,065	355,500
Depreciation	76,250	72,017	224,095	208,899
Amortization of Regulatory Assets, Net	30,406	54,031	78,453	97,437
Energy Efficiency Programs	40,129	30,240	86,897	71,606
Taxes Other Than Income Taxes	82,781	92,987	261,244	267,662
Total Operating Expenses	663,660	692,369	1,915,143	1,851,898
Operating Income/(Loss)	190,283	172,659	528,891	493,005
Interest Expense	39,520	37,609	112,274	113,107
Other Income, Net	4,831	7,098	11,564	20,722
Income Before Income Tax Expense	155,594	142,148	428,181	400,620
Income Tax Expense	43,907	41,818	101,219	102,010
Net Income	111,687	100,330	326,962	298,610
NSTAR Electric Company
Operating Revenues	878,669	939,460	2,358,174	2,400,324
Operating Expenses:
Purchased Power, Fuel and Transmission	300,726	383,208	859,227	981,895
Operations and Maintenance	120,917	123,634	342,804	344,478
Depreciation	74,664	70,616	220,303	205,210
Amortization of Regulatory Assets, Net	27,296	17,149	73,064	35,467
Energy Efficiency Programs	84,409	89,430	227,042	229,408
Taxes Other Than Income Taxes	51,266	49,927	144,314	145,740
Total Operating Expenses	659,278	733,964	1,866,754	1,942,198
Operating Income/(Loss)	219,391	205,496	491,420	458,126
Interest Expense	29,322	26,958	85,442	80,780
Other Income, Net	10,735	13,697	32,479	40,567
Income Before Income Tax Expense	200,804	192,235	438,457	417,913
Income Tax Expense	45,864	51,640	99,769	112,247
Net Income	154,940	140,595	338,688	305,666
Public Service Company of New Hampshire
Operating Revenues	280,431	290,203	797,766	792,700
Operating Expenses:
Purchased Power, Fuel and Transmission	101,381	100,763	300,680	293,975
Operations and Maintenance	50,838	55,429	156,197	153,296
Depreciation	23,539	23,223	69,720	69,524
Amortization of Regulatory Assets, Net	20,421	27,357	39,944	41,318
Energy Efficiency Programs	7,300	5,863	20,229	15,694
Taxes Other Than Income Taxes	12,487	21,095	50,523	59,775
Total Operating Expenses	215,966	233,730	637,293	633,582
Operating Income/(Loss)	64,465	56,473	160,473	159,118
Interest Expense	16,378	16,593	44,654	43,977
Other Income, Net	4,634	16,095	14,640	24,253
Income Before Income Tax Expense	52,721	55,975	130,459	139,394
Income Tax Expense	11,842	15,309	29,947	37,857
Net Income	$ 40,879	$ 40,666	$ 100,512	$ 101,537

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net Income	$ 320,764	$ 291,260	$ 664,655	$ 807,332
Other Comprehensive Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	367		945
Qualified Cash Flow Hedging Instruments		432		1,627
Changes in Unrealized Gains/(Losses) on Marketable Securities	169	(136)	1,268	(724)
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	1,088	1,110	5,770	5,918
Other Comprehensive Income (Loss), Net of Tax	1,624	1,406	7,983	6,821
Comprehensive Income Attributable to Noncontrolling Interests	(1,880)	(1,880)	(5,639)	(5,639)
Comprehensive Income Attributable to Common Shareholders	320,508	290,786	666,999	808,514
The Connecticut Light and Power Company
Net Income	111,687	100,330	326,962	298,610
Other Comprehensive Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	(7)		(20)
Qualified Cash Flow Hedging Instruments		(7)		58
Changes in Unrealized Gains/(Losses) on Marketable Securities	6	(5)	44	(21)
Other Comprehensive Income (Loss), Net of Tax	(1)	(12)	24	37
Comprehensive Income Attributable to Common Shareholders	111,686	100,318	326,986	298,647
NSTAR Electric Company
Net Income	154,940	140,595	338,688	305,666
Other Comprehensive Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	109		328
Qualified Cash Flow Hedging Instruments		110		328
Changes in Unrealized Gains/(Losses) on Marketable Securities	2	(1)	12	(6)
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	1	1	3	3
Other Comprehensive Income (Loss), Net of Tax	112	110	343	325
Comprehensive Income Attributable to Common Shareholders	155,052	140,705	339,031	305,991
Public Service Company of New Hampshire
Net Income	40,879	40,666	100,512	101,537
Other Comprehensive Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	268		806
Qualified Cash Flow Hedging Instruments		268		835
Changes in Unrealized Gains/(Losses) on Marketable Securities	10	(7)	75	(36)
Other Comprehensive Income (Loss), Net of Tax	278	261	881	799
Comprehensive Income Attributable to Common Shareholders	$ 41,157	$ 40,927	$ 101,393	$ 102,336

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Capital Surplus, Paid In	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	The Connecticut Light and Power Company	The Connecticut Light and Power CompanyCommon Shares	The Connecticut Light and Power CompanyCapital Surplus, Paid In	The Connecticut Light and Power CompanyRetained Earnings	The Connecticut Light and Power CompanyAccumulated Other Comprehensive Income (Loss)	NSTAR Electric Company	NSTAR Electric CompanyCommon Shares	NSTAR Electric CompanyCapital Surplus, Paid In	NSTAR Electric CompanyRetained Earnings	NSTAR Electric CompanyAccumulated Other Comprehensive Income (Loss)	Public Service Company of New Hampshire	Public Service Company of New HampshireCommon Shares	Public Service Company of New HampshireCapital Surplus, Paid In	Public Service Company of New HampshireRetained Earnings	Public Service Company of New HampshireAccumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2017		316,885,808						6,035,205					200					301
Balance at Dec. 31, 2017	$ 11,086,242	$ 1,669,392	$ 6,239,940	$ 3,561,084	$ (66,403)	$ (317,771)	$ 3,587,127	$ 60,352	$ 2,110,765	$ 1,415,741	$ 269	$ 3,446,080	$ 0	$ 1,502,942	$ 1,944,961	$ (1,823)	$ 1,350,594	$ 0	$ 843,134	$ 511,382	$ (3,922)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	271,426			271,426			98,568			98,568		77,149			77,149		35,093			35,093
Dividends on Common Shares	(160,027)			(160,027)			(60,000)			(60,000)		(161,000)			(161,000)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,390)			(1,390)		(490)			(490)
Long-Term Incentive Plan Activity	(15,320)		(15,320)
Capital Contributions from Eversource Parent							9,000		9,000			92,500		92,500
Other												1			1
Other Comprehensive Income	3,273				3,273		40				40	106				106	269				269
Balance (in shares) at Mar. 31, 2018		316,885,808						6,035,205					200					301
Balance at Mar. 31, 2018	11,183,714	$ 1,669,392	6,224,620	3,670,603	(63,130)	(317,771)	3,633,345	$ 60,352	2,119,765	1,452,919	309	3,454,346	$ 0	1,595,442	1,860,621	(1,717)	1,385,956	$ 0	843,134	546,475	(3,653)
Balance (in shares) at Dec. 31, 2017		316,885,808						6,035,205					200					301
Balance at Dec. 31, 2017	11,086,242	$ 1,669,392	6,239,940	3,561,084	(66,403)	(317,771)	3,587,127	$ 60,352	2,110,765	1,415,741	269	3,446,080	$ 0	1,502,942	1,944,961	(1,823)	1,350,594	$ 0	843,134	511,382	(3,922)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	807,332						298,610					305,666					101,537
Dividends on Preferred Stock	(5,600)
Other Comprehensive Income	6,821						37					325					799
Balance (in shares) at Sep. 30, 2018		316,885,808						6,035,205					200					301
Balance at Sep. 30, 2018	11,408,778	$ 1,669,392	6,234,044	3,882,695	(59,582)	(317,771)	3,921,605	$ 60,352	2,210,765	1,650,182	306	3,695,101	$ 0	1,608,442	2,088,157	(1,498)	1,147,930	$ 0	538,134	612,919	(3,123)
Balance (in shares) at Mar. 31, 2018		316,885,808						6,035,205					200					301
Balance at Mar. 31, 2018	11,183,714	$ 1,669,392	6,224,620	3,670,603	(63,130)	(317,771)	3,633,345	$ 60,352	2,119,765	1,452,919	309	3,454,346	$ 0	1,595,442	1,860,621	(1,717)	1,385,956	$ 0	843,134	546,475	(3,653)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	244,647			244,647			99,712			99,712		87,921			87,921		25,779			25,779
Dividends on Common Shares	(160,027)			(160,027)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,390)			(1,390)		(490)			(490)
Long-Term Incentive Plan Activity	4,627		4,627
Capital Contributions from Eversource Parent							91,000		91,000			8,000		8,000			225,000		225,000
Return of Capital																	(530,000)		(530,000)
Other																	(1)			(1)
Other Comprehensive Income	2,142				2,142		9				9	109				109	269				269
Balance (in shares) at Jun. 30, 2018		316,885,808						6,035,205					200					301
Balance at Jun. 30, 2018	11,273,223	$ 1,669,392	6,229,247	3,753,343	(60,988)	(317,771)	3,822,676	$ 60,352	2,210,765	1,551,241	318	3,549,886	$ 0	1,603,442	1,948,052	(1,608)	1,107,003	$ 0	538,134	572,253	(3,384)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	291,260			291,260			100,330			100,330		140,595			140,595		40,666			40,666
Dividends on Common Shares	(160,028)			(160,028)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,389)			(1,389)		(490)			(490)
Long-Term Incentive Plan Activity	4,797		4,797
Capital Contributions from Eversource Parent												5,000		5,000
Other Comprehensive Income	1,406				1,406		(12)				(12)	110				110	261				261
Balance (in shares) at Sep. 30, 2018		316,885,808						6,035,205					200					301
Balance at Sep. 30, 2018	$ 11,408,778	$ 1,669,392	6,234,044	3,882,695	(59,582)	(317,771)	3,921,605	$ 60,352	2,210,765	1,650,182	306	3,695,101	$ 0	1,608,442	2,088,157	(1,498)	1,147,930	$ 0	538,134	612,919	(3,123)
Balance (in shares) at Dec. 31, 2018	316,885,808	316,885,808						6,035,205					200					301
Balance at Dec. 31, 2018	$ 11,486,817	$ 1,669,392	6,241,222	3,953,974	(60,000)	(317,771)	4,199,317	$ 60,352	2,410,765	1,727,899	301	3,730,155	$ 0	1,633,442	2,098,091	(1,378)	1,302,541	$ 0	678,134	627,258	(2,851)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	310,558			310,558			110,471			110,471		94,014			94,014		32,781			32,781
Dividends on Common Shares	(169,757)			(169,757)			(99,000)			(99,000)		(60,600)			(60,600)		(19,000)			(19,000)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,390)			(1,390)		(490)			(490)
Long-Term Incentive Plan Activity	(16,609)		(16,609)
Issuance of Treasury Shares (in shares)		461,662
Issuance of Treasury Shares	26,109		17,476			8,633
Capital Contributions from Eversource Parent												20,000		20,000
Other Comprehensive Income	2,196				2,196		17				17	117				117	307				307
Balance (in shares) at Mar. 31, 2019		317,347,470						6,035,205					200					301
Balance at Mar. 31, 2019	$ 11,637,434	$ 1,669,392	6,242,089	4,092,895	(57,804)	(309,138)	4,209,415	$ 60,352	2,410,765	1,737,980	318	3,783,196	$ 0	1,653,442	2,131,015	(1,261)	1,316,629	$ 0	678,134	641,039	(2,544)
Balance (in shares) at Dec. 31, 2018	316,885,808	316,885,808						6,035,205					200					301
Balance at Dec. 31, 2018	$ 11,486,817	$ 1,669,392	6,241,222	3,953,974	(60,000)	(317,771)	4,199,317	$ 60,352	2,410,765	1,727,899	301	3,730,155	$ 0	1,633,442	2,098,091	(1,378)	1,302,541	$ 0	678,134	627,258	(2,851)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	664,655						326,962					338,688					100,512
Dividends on Preferred Stock	(5,600)
Other Comprehensive Income	$ 7,983						24					343					881
Balance (in shares) at Sep. 30, 2019	323,733,423	323,733,423						6,035,205					200					301
Balance at Sep. 30, 2019	$ 12,121,614	$ 1,699,292	6,675,889	4,100,220	(52,017)	(301,770)	4,180,334	$ 60,352	2,410,765	1,708,892	325	3,915,916	$ 0	1,663,442	2,253,509	(1,035)	1,151,934	$ 0	678,134	475,770	(1,970)
Balance (in shares) at Mar. 31, 2019		317,347,470						6,035,205					200					301
Balance at Mar. 31, 2019	11,637,434	$ 1,669,392	6,242,089	4,092,895	(57,804)	(309,138)	4,209,415	$ 60,352	2,410,765	1,737,980	318	3,783,196	$ 0	1,653,442	2,131,015	(1,261)	1,316,629	$ 0	678,134	641,039	(2,544)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	33,334			33,334			104,804			104,804		89,734			89,734		26,852			26,852
Dividends on Common Shares	(169,857)			(169,857)			(176,400)			(176,400)		(121,200)			(121,200)		(214,000)			(214,000)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,390)			(1,390)		(490)			(490)
Issuance of Common Shares (in shares)		5,980,000
Issuance of Common Shares	433,550	$ 29,900	403,650
Long-Term Incentive Plan Activity	6,470		6,470
Issuance of Treasury Shares (in shares)		246,969
Issuance of Treasury Shares	18,027		13,448			4,579
Capital Stock Expense	(6,648)		(6,648)
Other							1			1
Other Comprehensive Income	4,163				4,163		8				8	114				114	296				296
Balance (in shares) at Jun. 30, 2019		323,574,439						6,035,205					200					301
Balance at Jun. 30, 2019	11,954,593	$ 1,699,292	6,659,009	3,954,492	(53,641)	(304,559)	4,136,438	$ 60,352	2,410,765	1,664,995	326	3,751,354	$ 0	1,653,442	2,099,059	(1,147)	1,129,777	$ 0	678,134	453,891	(2,248)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	320,764			320,764			111,687			111,687		154,940			154,940		40,879			40,879
Dividends on Common Shares	(173,156)			(173,156)			(66,400)			(66,400)							(19,000)			(19,000)
Dividends on Preferred Stock	(1,880)			(1,880)			(1,390)			(1,390)		(490)			(490)
Long-Term Incentive Plan Activity	6,697		6,697
Issuance of Treasury Shares (in shares)		158,984
Issuance of Treasury Shares	12,972		10,183			2,789
Capital Contributions from Eversource Parent												10,000		10,000
Other Comprehensive Income	$ 1,624				1,624		(1)				(1)	112				112	278				278
Balance (in shares) at Sep. 30, 2019	323,733,423	323,733,423						6,035,205					200					301
Balance at Sep. 30, 2019	$ 12,121,614	$ 1,699,292	$ 6,675,889	$ 4,100,220	$ (52,017)	$ (301,770)	$ 4,180,334	$ 60,352	$ 2,410,765	$ 1,708,892	$ 325	$ 3,915,916	$ 0	$ 1,663,442	$ 2,253,509	$ (1,035)	$ 1,151,934	$ 0	$ 678,134	$ 475,770	$ (1,970)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends on Common Shares (in dollars per share)	$ 0.535	$ 0.535	$ 0.535	$ 0.505	$ 0.505	$ 0.505
Issuance of Common Shares, par value (in dollars per share)	$ 5	$ 5

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net Income	$ 664,655	$ 807,332
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	656,632	612,077
Deferred Income Taxes	73,487	70,402
Uncollectible Expense	46,417	50,720
Pension, SERP and PBOP Expense, Net	18,507	5,192
Pension and PBOP Contributions	(120,373)	(188,874)
Regulatory Over/(Under) Recoveries, Net	80,688	189,932
Amortization	183,760	174,108
Proceeds from DOE Spent Nuclear Fuel Litigation	68,840	0
Impairment of Northern Pass Transmission	239,644	0
Other	(185,625)	(129,039)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(57,011)	(212,326)
Fuel, Materials, Supplies and REC Inventory	34,030	44,702
Taxes Receivable/Accrued, Net	53,687	70,885
Accounts Payable	(157,355)	(72,591)
Other Current Assets and Liabilities, Net	(105,133)	(14,858)
Net Cash Flows Provided by Operating Activities	1,494,850	1,407,662
Investing Activities:
Investments in Property, Plant and Equipment	(2,129,037)	(1,885,081)
Proceeds from Sales of Marketable Securities	458,322	405,276
Purchases of Marketable Securities	(405,095)	(396,277)
Proceeds from the Sale of PSNH Generation Assets	0	193,924
Investments in Unconsolidated Affiliates, Net	(374,913)	(27,342)
Other Investing Activities	(1,126)	3,937
Net Cash Flows Used in Investing Activities	(2,451,849)	(1,705,563)
Financing Activities:
Issuance of Common Shares, Net of Issuance Costs	426,902	0
Cash Dividends on Common Shares	(495,571)	(480,082)
Cash Dividends on Preferred Stock	(5,639)	(5,639)
(Decrease)/Increase in Notes Payable	(197,500)	(222,110)
Issuance of Rate Reduction Bonds	0	635,663
Repayment of Rate Reduction Bonds	(52,332)	0
Issuance of Long-Term Debt	1,475,000	1,300,000
Retirement of Long-Term Debt	(250,855)	(860,855)
Other Financing Activities	(450)	(20,361)
Net Cash Flows Provided by Financing Activities	899,555	346,616
Net (Decrease)/Increase in Cash and Restricted Cash	(57,444)	48,715
Cash and Restricted Cash - Beginning of Period	209,324	85,890
Cash and Restricted Cash - End of Period	151,880	134,605
The Connecticut Light and Power Company
Operating Activities:
Net Income	326,962	298,610
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	224,095	208,899
Deferred Income Taxes	19,999	28,637
Uncollectible Expense	12,084	12,135
Pension, SERP and PBOP Expense, Net	9,843	6,594
Pension Contributions	(24,000)	(41,150)
Regulatory Over/(Under) Recoveries, Net	32,435	(1,136)
Amortization of Regulatory Assets, Net	78,453	97,437
Other	(66,737)	(55,827)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(70,996)	(126,513)
Taxes Receivable/Accrued, Net	32,708	72,702
Accounts Payable	8,604	(15,303)
Other Current Assets and Liabilities, Net	(51,937)	(33,965)
Net Cash Flows Provided by Operating Activities	531,513	451,120
Investing Activities:
Investments in Property, Plant and Equipment	(699,288)	(660,673)
Other Investing Activities	645	167
Net Cash Flows Used in Investing Activities	(698,643)	(660,506)
Financing Activities:
Cash Dividends on Common Shares	(341,800)	(60,000)
Cash Dividends on Preferred Stock	(4,169)	(4,169)
Capital Contributions from Eversource Parent	0	100,000
Issuance of Long-Term Debt	500,000	500,000
Retirement of Long-Term Debt	(250,000)	(300,000)
Increase/(Decrease) in Notes Payable to Eversource Parent	173,100	(23,600)
Other Financing Activities	12,667	(7,584)
Net Cash Flows Provided by Financing Activities	89,798	204,647
Net (Decrease)/Increase in Cash and Restricted Cash	(77,332)	(4,739)
Cash and Restricted Cash - Beginning of Period	91,613	9,619
Cash and Restricted Cash - End of Period	14,281	4,880
NSTAR Electric Company
Operating Activities:
Net Income	338,688	305,666
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	220,303	205,210
Deferred Income Taxes	11,080	16,203
Uncollectible Expense	18,598	20,433
Pension, SERP and PBOP Income, Net	(9,779)	(15,855)
Pension and PBOP Contributions	(4,910)	(60,454)
Regulatory Over/(Under) Recoveries, Net	46,543	180,797
Amortization of Regulatory Assets, Net	73,064	35,467
Other	(50,685)	(49,178)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(68,167)	(155,669)
Fuel, Materials, Supplies and REC Inventory	24,033	29,156
Taxes Receivable/Accrued, Net	66,917	42,148
Accounts Payable	(47,256)	(13,178)
Other Current Assets and Liabilities, Net	(31,495)	33,543
Net Cash Flows Provided by Operating Activities	586,934	574,289
Investing Activities:
Investments in Property, Plant and Equipment	(636,214)	(538,973)
Other Investing Activities	67	46
Net Cash Flows Used in Investing Activities	(636,147)	(538,927)
Financing Activities:
Cash Dividends on Common Shares	(181,800)	(161,000)
Cash Dividends on Preferred Stock	(1,470)	(1,470)
Capital Contributions from Eversource Parent	30,000	105,500
Increase in Notes Payable to Eversource Parent	48,700	16,000
(Decrease)/Increase in Notes Payable	(250,500)	6,500
Issuance of Long-Term Debt	400,000	0
Other Financing Activities	(3,868)	(239)
Net Cash Flows Provided by Financing Activities	41,062	(34,709)
Net (Decrease)/Increase in Cash and Restricted Cash	(8,151)	653
Cash and Restricted Cash - Beginning of Period	14,659	14,708
Cash and Restricted Cash - End of Period	6,508	15,361
Public Service Company of New Hampshire
Operating Activities:
Net Income	100,512	101,537
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	69,720	69,524
Deferred Income Taxes	12,960	11,473
Uncollectible Expense	4,977	4,865
Pension, SERP and PBOP Expense, Net	683	1,106
Pension Contributions	(15,400)	0
Regulatory Over/(Under) Recoveries, Net	(13,347)	(19,764)
Amortization of Regulatory Assets, Net	39,944	41,318
Other	(23,865)	(9,075)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(13,498)	(32,819)
Fuel, Materials, Supplies and REC Inventory	13,545	14,555
Taxes Receivable/Accrued, Net	31,909	10,929
Accounts Payable	(12,100)	(3,828)
Other Current Assets and Liabilities, Net	6,754	27,844
Net Cash Flows Provided by Operating Activities	202,794	217,665
Investing Activities:
Investments in Property, Plant and Equipment	(209,031)	(236,206)
Proceeds from the Sale of PSNH Generation Assets	0	193,924
Other Investing Activities	904	5,149
Net Cash Flows Used in Investing Activities	(208,127)	(37,133)
Financing Activities:
Cash Dividends on Common Shares	(252,000)	(150,000)
Capital Contributions from Eversource Parent	0	225,000
Return of Capital	0	(530,000)
Issuance of Rate Reduction Bonds	0	635,663
Repayment of Rate Reduction Bonds	(52,332)	0
Issuance of Long-Term Debt	300,000	0
Retirement of Long-Term Debt	0	(110,000)
Increase/(Decrease) in Notes Payable to Eversource Parent	(14,900)	(216,300)
Other Financing Activities	(4,146)	1,080
Net Cash Flows Provided by Financing Activities	(23,378)	(144,557)
Net (Decrease)/Increase in Cash and Restricted Cash	(28,711)	35,975
Cash and Restricted Cash - Beginning of Period	52,723	2,191
Cash and Restricted Cash - End of Period	$ 24,012	$ 38,166

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A. Basis of Presentation Eversource Energy is a public utility holding company primarily engaged, through its wholly-owned regulated utility subsidiaries, in the energy delivery business. Eversource Energy's wholly-owned regulated utility subsidiaries consist of CL&P, NSTAR Electric and PSNH (electric utilities), Yankee Gas and NSTAR Gas (natural gas utilities) and Aquarion (water utilities). Eversource provides energy delivery and/or water service to approximately four million electric, natural gas and water customers through eight regulated utilities in Connecticut, Massachusetts and New Hampshire. The unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH include the accounts of each of their respective subsidiaries. Intercompany transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH and the unaudited condensed financial statements of CL&P are herein collectively referred to as the "financial statements." The combined notes to the financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures included in annual financial statements prepared in accordance with GAAP have been omitted pursuant to such rules and regulations. The accompanying financial statements should be read in conjunction with the Combined Notes to Financial Statements included in Item 8, "Financial Statements and Supplementary Data," of the Eversource 2018 Form 10-K, which was filed with the SEC on February 26, 2019. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource's, CL&P's, NSTAR Electric's and PSNH's financial position as of September 30, 2019 and December 31, 2018 , and the results of operations, comprehensive income and common shareholders' equity for the three and nine months ended September 30, 2019 and 2018 , and the cash flows for the nine months ended September 30, 2019 and 2018 . The results of operations and comprehensive income for the three and nine months ended September 30, 2019 and 2018 and the cash flows for the nine months ended September 30, 2019 and 2018 are not necessarily indicative of the results expected for a full year. Eversource consolidates CYAPC and YAEC because CL&P's, NSTAR Electric's and PSNH's combined ownership and voting interests in each of these entities is greater than 50 percent. Intercompany transactions between CL&P, NSTAR Electric, PSNH and the CYAPC and YAEC companies have been eliminated in consolidation of the Eversource financial statements. Eversource's utility subsidiaries' electric, natural gas and water distribution and transmission businesses are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for entities with rate-regulated operations, which considers the effect of regulation on the differences in the timing of the recognition of certain revenues and expenses from those of other businesses and industries. See Note 2, "Regulatory Accounting," for further information. Certain reclassifications of prior period data were made in the accompanying financial statements to conform to the current period presentation. B. Accounting Standards Accounting Standards Issued but Not Yet Effective: In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326), which provides a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. Under the new guidance, immediate recognition of all credit losses expected over the life of a financial instrument is required. The standard is effective January 1, 2020 a nd requires a modified retrospective method through a cumulative effect adjustment to retained earnings. The Company is assessing the impacts of this standard on the accounting for credit losses on its financial instruments, including accounts receivable, and does not expect it to have a material impact on the financial statements. Accounting Standards Recently Adopted: On January 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842), which amended existing lease accounting guidance. The Company applied the Topic 842 lease criteria to new leases and lease renewals entered into effective on or after January 1, 2019. The ASU required balance sheet recognition of leases deemed to be operating leases as well as additional disclosure requirements. The recognition, measurement and presentation of expenses and cash flows were not significantly changed. The Company also adopted the modified retrospective transition method allowed in ASU 2018-11, Leases (Topic 842) - Targeted Improvements , which allowed the Company to adopt the new leases standard as of January 1, 2019, with prior periods presented in the financial statements continuing to follow existing lease accounting guidance under Topic 840 (Leases) in the accounting literature. Implementation of ASU 2018-11 had no effect on retained earnings, and the requirements of the new lease standard (Topic 842) are reflected in the 2019 financial statements and footnotes. The Company elected the practical expedient package whereby it did not need to reassess whether or not an existing contract is or contains a lease or whether a lease is an operating or capital lease, and it did not need to reassess initial direct costs for leases. Election of this practical expedient allowed us to carry forward our historical lease classifications. The Company elected the practical expedient to not reevaluate land easements existing at adoption if they were not previously accounted for as leases. The Company also elected to use the discount rate as of the January 1, 2019 implementation date to discount its operating lease liabilities. The Company did not elect the hindsight practical expedient to determine the lease term for existing leases. The Company determined the impact the ASUs had on its financial statements by reviewing its lease population and identifying lease data needed for the disclosure requirements. The Company implemented a new lease accounting system in 2019 to ensure ongoing compliance with the ASU’s requirements. Adoption of the new standard resulted in the recording of operating lease liabilities and right-of-use assets on the balance sheet upon transition at January 1, 2019 of $58.0 million at Eversource, $25.3 million at NSTAR Electric, $0.6 million at CL&P, and $0.6 million at PSNH. Implementation of the new guidance did not have an impact on each company’s results of operations or cash flows. C. Impairment of Northern Pass Transmission Northern Pass was Eversource's planned 1,090 MW HVDC transmission line that would interconnect from the Québec-New Hampshire border to Franklin, New Hampshire and an associated alternating current radial transmission line between Franklin and Deerfield, New Hampshire. As a result of a final decision received on July 19, 2019 from the New Hampshire Supreme Court, whereby the court issued a decision denying Northern Pass’ appeal and affirming the NHSEC’s evaluation and decision that denied Northern Pass’ siting application on NPT, Eversource concluded that construction of NPT was no longer probable. As a result, substantially all of the capitalized project costs, which totaled $318 million , certain of which are subject to cost reimbursement agreements, were impaired. Based on the conclusion that the construction of Northern Pass was not probable, Eversource recorded an impairment charge in the second quarter of 2019 for all of the project costs associated with Northern Pass, which were primarily engineering design, siting, permitting and legal costs, along with appropriate allowances for funds used during construction, and recognized a receivable for certain cost reimbursement agreements. Additionally, Eversource recorded an impairment charge associated with the land acquired to construct Northern Pass in order to recognize the land at its estimated fair value based on assessed values and transaction costs. In total, this resulted in a pre-tax impairment charge of $239.6 million within Operating Income on the statement of income for the nine months ended September 30, 2019, and was reflected in the Electric Transmission segment. The after-tax impact of the second quarter impairment charge was $204.4 million , or $0.64 per share, after giving effect to the estimated fair value of the related land, reimbursement agreements, and the impact of expected income tax benefits associated with the impairment charge. Eversource does not expect any significant estimated future cash expenditures associated with this impairment charge. D. Provision for Uncollectible Accounts Eversource, including CL&P, NSTAR Electric and PSNH, presents its receivables at estimated net realizable value by maintaining a provision for uncollectible accounts. This provision is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. The estimate is based upon historical collection and write-off experience and management's assessment of collectability from customers. Management continuously assesses the collectability of receivables and adjusts collectability estimates based on actual experience. Receivable balances are written off against the provision for uncollectible accounts when the customer accounts are terminated and these balances are deemed to be uncollectible. The PURA allows CL&P and Yankee Gas to accelerate the recovery of accounts receivable balances attributable to qualified customers under financial or medical duress (uncollectible hardship accounts receivable) outstanding for greater than 180 days and 90 days , respectively. The DPU allows NSTAR Electric and NSTAR Gas to recover in rates amounts associated with certain uncollectible hardship accounts receivable. These uncollectible hardship customer account balances are included in Regulatory Assets or Other Long-Term Assets on the balance sheets. The total provision for uncollectible accounts is included in Receivables, Net on the balance sheets. The provision for uncollectible hardship accounts is included in the total uncollectible provision balance. The provision balances are as follows: Total Provision for Uncollectible Accounts Provision for Uncollectible Hardship Accounts (Millions of Dollars) As of September 30, 2019 As of December 31, 2018 As of September 30, 2019 As of December 31, 2018 Eversource $ 225.5 $ 212.7 $ 146.5 $ 131.5 CL&P 94.1 88.0 77.8 71.9 NSTAR Electric 80.7 74.5 49.4 42.5 PSNH 10.6 11.1 — — Uncollectible expense associated with customers' accounts receivable included in Operations and Maintenance expense on the statements of income is as follows: For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Eversource $ 14.9 $ 21.5 $ 46.4 $ 50.7 CL&P 4.5 4.4 12.1 12.1 NSTAR Electric 7.0 9.1 18.6 20.4 PSNH 1.8 1.6 5.0 4.9 E. Fair Value Measurements Fair value measurement guidance is applied to derivative contracts that are not elected or designated as "normal purchases" or "normal sales" ("normal") and to the marketable securities held in trusts. Fair value measurement guidance is also applied to valuations of the investments used to calculate the funded status of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial assets such as goodwill and AROs, and the estimated fair value of preferred stock, long-term debt and RRBs. Fair Value Hierarchy: In measuring fair value, Eversource uses observable market data when available in order to minimize the use of unobservable inputs. Inputs used in fair value measurements are categorized into three fair value hierarchy levels for disclosure purposes. The entire fair value measurement is categorized based on the lowest level of input that is significant to the fair value measurement. Eversource evaluates the classification of assets and liabilities measured at fair value on a quarterly basis, and Eversource's policy is to recognize transfers between levels of the fair value hierarchy as of the end of the reporting period. The three levels of the fair value hierarchy are described below: Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 - Inputs are quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs are observable. Level 3 - Quoted market prices are not available. Fair value is derived from valuation techniques in which one or more significant inputs or assumptions are unobservable. Where possible, valuation techniques incorporate observable market inputs that can be validated to external sources such as industry exchanges, including prices of energy and energy-related products. Uncategorized - Investments that are measured at net asset value are not categorized within the fair value hierarchy. Determination of Fair Value: The valuation techniques and inputs used in Eversource's fair value measurements are described in Note 4, "Derivative Instruments," Note 5, "Marketable Securities," and Note 11, "Fair Value of Financial Instruments," to the financial statements. F. Investments in Unconsolidated Affiliates Investments in Offshore Wind Business: Eversource's offshore wind business includes ownership interests in North East Offshore and Bay State Wind, which together hold power purchase agreements and contracts for the Revolution Wind, South Fork Wind and Sunrise Wind projects. Eversource's offshore wind projects are being developed in joint and equal partnership with Ørsted . On February 8, 2019, Eversource and Ørsted entered into an equal partnership to acquire key offshore wind assets in the Northeast, where Eversource owns 50 percent of these assets. Eversource's initial payment and contribution under the terms of the partnership agreements totaled approximately $225 million for a 50 percent ownership interest in North East Offshore, which holds the Revolution Wind and South Fork Wind projects, as well as a 257 square-mile lease off the coasts of Massachusetts and Rhode Island. Eversource also has a 50 percent ownership interest in Bay State Wind, which holds the Sunrise Wind project. These equity investments are included in long-term assets on the balance sheet, and earnings impacts are included in Other Income, Net on the statement of income. As of September 30, 2019 , Eversource's total equity investment balance in its offshore wind business was $637.2 million . In the third quarter of 2019, Eversource made additional capital contributions of $133.6 million . G. Other Income, Net The components of Other Income, Net on the statements of income were as follows: For the Three Months Ended September 30, 2019 September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Pension, SERP and PBOP Non-Service Income Components $ 10.1 $ 1.7 $ 5.6 $ 1.4 $ 14.8 $ 2.0 $ 9.0 $ 2.0 AFUDC Equity 10.5 3.6 5.6 1.0 12.0 3.3 4.2 — Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates (1) 6.1 — 0.2 — (27.9 ) — 0.2 — Investment Income/(Loss) (2.8 ) (0.8 ) (0.9 ) (0.3 ) 1.8 0.7 (0.4 ) 0.1 Interest Income (2) 2.9 0.3 0.1 2.5 10.8 0.9 0.2 9.6 Gain on Sale of Property — — — — 5.0 — 0.5 4.4 Other 0.2 — 0.1 — 0.2 0.2 — — Total Other Income, Net $ 27.0 $ 4.8 $ 10.7 $ 4.6 $ 16.7 $ 7.1 $ 13.7 $ 16.1 For the Nine Months Ended September 30, 2019 September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Pension, SERP and PBOP Non-Service Income Components $ 23.2 $ 0.1 $ 18.0 $ 3.5 $ 44.6 $ 7.3 $ 26.8 $ 6.4 AFUDC Equity 34.5 9.4 14.7 2.1 32.6 9.4 11.5 — Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates (1) 37.0 0.2 0.6 — (0.4 ) — 0.6 — Investment Income/(Loss) (2.3 ) 0.9 (1.5 ) — 2.2 0.9 0.6 0.2 Interest Income (2) 10.8 1.1 0.5 9.0 16.2 2.9 0.6 13.3 Gain on Sale of Property 0.2 — — — 5.0 — 0.5 4.4 Other 0.4 (0.1 ) 0.2 — 0.5 0.2 — — Total Other Income, Net $ 103.8 $ 11.6 $ 32.5 $ 14.6 $ 100.7 $ 20.7 $ 40.6 $ 24.3 (1) For the three and nine months ended September 30, 2018, equity in earnings/(loss) and impairment of unconsolidated affiliates includes an other-than-temporary impairment of $32.9 million of the Access Northeast project investment. For the nine months ended September 30, 2019 and 2018, equity in earnings includes $20.4 million and $17.6 million , respectively, of unrealized gains associated with an investment in a renewable energy fund. (2) For the nine months ended September 30, 2019, see Note 2, "Regulatory Accounting," for further information on $5.2 million of interest income recognized in 2019 for the equity return component of carrying charges on storm costs at PSNH. For the three and nine months ended September 30, 2018, PSNH recognized $8.7 million for the equity return component of carrying charges on storm costs incurred from August 2011 through March 2013. H. Other Taxes Eversource's companies that serve customers in Connecticut collect gross receipts taxes levied by the state of Connecticut from their customers. These gross receipts taxes are recorded separately with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the statements of income as follows: For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Eversource $ 42.6 $ 43.5 $ 124.0 $ 122.5 CL&P 39.8 40.6 107.8 107.7 As agents for state and local governments, Eversource's companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income. Separate from above were amounts recorded as Taxes Other Than Income Taxes related to the remittance to the State of Connecticut of energy efficiency funds collected from customers in Operating Revenues. These amounts were $21.4 million for the nine months ended September 30, 2019 , and $10.7 million and $36.1 million for the three and nine months ended September 30, 2018, respectively. Energy efficiency funds collected from customers after July 1, 2019 are no longer subject to remittance to the State of Connecticut. These amounts were recorded separately, with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the Eversource and CL&P statements of income. I. Supplemental Cash Flow Information Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of September 30, 2019 As of September 30, 2018 Eversource $ 317.8 $ 303.7 CL&P 107.6 103.0 NSTAR Electric 79.0 62.5 PSNH 35.8 48.3 Beginning in 2019, Eversource began issuing treasury shares to satisfy awards under the Company's incentive plans, shares issued under the dividend reinvestment and share purchase plan, and matching contributions under the Eversource 401k Plan. The issuance of treasury shares represents a non-cash transaction, as the treasury shares were used to fulfill Eversource's obligations that require the issuance of common shares. The following table reconciles cash as reported on the balance sheets to the cash and restricted cash balance as reported on the statements of cash flows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Cash as reported on the Balance Sheets $ 22.7 $ 9.3 $ 0.3 $ 1.6 $ 108.1 $ 87.7 $ 1.6 $ 1.4 Restricted cash included in: Prepayments and Other Current Assets 37.7 4.6 6.1 18.5 72.1 3.5 13.0 47.5 Marketable Securities 19.6 0.4 0.1 0.7 25.9 0.4 0.1 0.6 Other Long-Term Assets 71.9 — — 3.2 3.2 — — 3.2 Cash and Restricted Cash reported on the Statements of Cash Flows $ 151.9 $ 14.3 $ 6.5 $ 24.0 $ 209.3 $ 91.6 $ 14.7 $ 52.7 Restricted cash included in Prepayments and Other Current Assets primarily represents cash collections related to the PSNH RRB customer charges that are held in trust, and required ISO-NE cash deposits. R estricted cash included in Marketable Securities represents money market funds held in trusts to fund certain non-qualified executive benefits and restricted trusts to fund CYAPC and YAEC's spent nuclear fuel storage facilities obligations. Restricted cash included in Other Long-Term Assets at Eversource primarily relates to DOE Phase IV damages proceeds received at CYAPC and YAEC in the second quarter of 2019. See Note 9D, "Commitments and Contingencies - Spent Nuclear Fuel Obligations - Yankee Companies," for further information.

REGULATORY ACCOUNTING

REGULATORY ACCOUNTING	9 Months Ended
	Sep. 30, 2019
Regulated Operations [Abstract]
REGULATORY ACCOUNTING	REGULATORY ACCOUNTING Eversource's utility companies are subject to rate regulation that is based on cost recovery and meets the criteria for application of accounting guidance for rate-regulated operations, which considers the effect of regulation on the timing of the recognition of certain revenues and expenses. The regulated companies' financial statements reflect the effects of the rate-making process. The rates charged to the customers of Eversource's regulated companies are designed to collect each company's costs to provide service, including a return on investment. Management believes it is probable that each of the regulated companies will recover its respective investments in long-lived assets, including regulatory assets. If management were to determine that it could no longer apply the accounting guidance applicable to rate-regulated enterprises to any of the regulated companies' operations, or if management could not conclude it is probable that costs would be recovered from customers in future rates, the costs would be charged to net income in the period in which the determination is made. Regulatory Assets: The components of regulatory assets were as follows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Benefit Costs $ 1,835.1 $ 400.5 $ 542.8 $ 148.5 $ 1,914.8 $ 424.7 $ 544.4 $ 169.6 Income Taxes, Net 713.4 460.2 108.6 11.4 728.6 454.4 105.9 8.3 Securitized Stranded Costs 576.1 — — 576.1 608.4 — — 608.4 Storm Restoration Costs, Net 508.9 258.9 190.2 59.8 576.0 302.6 212.9 60.5 Regulatory Tracker Mechanisms 282.7 56.5 121.1 58.1 316.0 33.2 169.1 67.3 Derivative Liabilities 345.8 342.3 — — 356.5 356.5 — — Goodwill-related 335.7 — 288.3 — 348.4 — 299.1 — Asset Retirement Obligations 101.3 33.8 51.7 3.5 89.2 32.3 42.2 3.3 Other Regulatory Assets 131.8 25.6 57.6 13.0 208.0 27.0 64.6 12.1 Total Regulatory Assets 4,830.8 1,577.8 1,360.3 870.4 5,145.9 1,630.7 1,438.2 929.5 Less: Current Portion 538.2 173.3 201.2 78.1 514.8 125.2 241.7 67.2 Total Long-Term Regulatory Assets $ 4,292.6 $ 1,404.5 $ 1,159.1 $ 792.3 $ 4,631.1 $ 1,505.5 $ 1,196.5 $ 862.3 Storm Filings: On November 16, 2018, CL&P filed for recovery of $153 million of storm costs incurred from October 2017 through May 2018, with recovery over six years to begin May 1, 2019. Through the course of the proceeding, CL&P updated its request to $145.5 million to reflect final invoicing and capitalization amounts. On April 17, 2019, PURA authorized recovery of $141.0 million as part of storm cost recovery and the remainder to be recorded to plant or other balance sheet accounts. CL&P began recovery of the $141.0 million in distribution rates effective May 1, 2019. On March 26, 2019, the NHPUC approved the recovery of $38.1 million , plus carrying charges, of storm costs incurred from December 2013 through April 2016 and the transfer of funding from PSNH’s major storm reserve to recover those costs. The costs of these storms (excluding the equity return component of the carrying charges) were deferred as regulatory assets, and the funding reserve collected from customers was accrued as a regulatory liability. As a result of the duration of time between incurring storm costs in December 2013 through April 2016 and final approval from the NHPUC in 2019, PSNH recognized $5.2 million (pre-tax) for the equity return component of the carrying charges within Other Income, Net on the statement of income in the first quarter of 2019, which has been collected from customers. Also included in the March 26, 2019 NHPUC approval is a prospective requirement for PSNH to annually net its storm funding reserve collected from customers against deferred storm costs. In addition, on June 27, 2019, the NHPUC approved a temporary rate settlement that permits PSNH to recover approximately $68.5 million in unrecovered storm costs over a five -year period beginning August 1, 2019, with debt carrying charges. Regulatory Costs in Long-Term Assets: Eversource's regulated companies had $144.3 million (including $44.7 million for CL&P, $61.5 million for NSTAR Electric and $17.8 million for PSNH) and $122.9 million (including $42.1 million for CL&P, $49.3 million for NSTAR Electric and $12.2 million for PSNH) of additional regulatory costs as of September 30, 2019 and December 31, 2018 , respectively, that were included in long-term assets on the balance sheets. These amounts represent incurred costs for which recovery has not yet been specifically approved by the applicable regulatory agency. However, based on regulatory policies or past precedent on similar costs, management believes it is probable that these costs will ultimately be approved and recovered from customers in rates. Regulatory Liabilities: The components of regulatory liabilities were as follows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH EDIT due to Tax Cuts and Jobs Act $ 2,846.9 $ 1,025.7 $ 1,083.2 $ 394.0 $ 2,883.0 $ 1,031.0 $ 1,103.7 $ 396.4 Cost of Removal 552.0 56.3 325.2 20.5 521.0 39.9 307.1 22.1 Benefit Costs 79.7 — 67.4 — 91.2 — 76.9 — Regulatory Tracker Mechanisms 404.3 169.7 167.9 43.3 309.0 89.5 163.7 48.3 AFUDC - Transmission 72.6 46.4 26.2 — 70.7 47.4 23.3 — Revenue Subject to Refund due to Tax Cuts and Jobs Act 18.3 — — 9.0 24.6 — — 12.6 Other Regulatory Liabilities 111.9 29.9 49.1 6.0 80.2 24.0 29.2 4.2 Total Regulatory Liabilities 4,085.7 1,328.0 1,719.0 472.8 3,979.7 1,231.8 1,703.9 483.6 Less: Current Portion 441.2 168.1 199.4 54.7 370.2 109.6 190.6 55.5 Total Long-Term Regulatory Liabilities $ 3,644.5 $ 1,159.9 $ 1,519.6 $ 418.1 $ 3,609.5 $ 1,122.2 $ 1,513.3 $ 428.1

PROPERTY, PLANT AND EQUIPMENT A

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION The following tables summarize property, plant and equipment by asset category: Eversource As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Distribution - Electric $ 15,737.6 $ 15,071.1 Distribution - Natural Gas 3,723.7 3,546.2 Transmission - Electric 10,570.6 10,153.9 Distribution - Water 1,686.3 1,639.8 Solar 199.2 164.1 Utility 31,917.4 30,575.1 Other (1) 935.2 778.6 Property, Plant and Equipment, Gross 32,852.6 31,353.7 Less: Accumulated Depreciation Utility (7,417.6 ) (7,126.2 ) Other (375.1 ) (336.7 ) Total Accumulated Depreciation (7,792.7 ) (7,462.9 ) Property, Plant and Equipment, Net 25,059.9 23,890.8 Construction Work in Progress 1,852.0 1,719.6 Total Property, Plant and Equipment, Net $ 26,911.9 $ 25,610.4 As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Distribution - Electric $ 6,417.9 $ 7,102.3 $ 2,257.7 $ 6,176.4 $ 6,756.4 $ 2,178.6 Transmission - Electric 4,938.5 4,186.6 1,440.7 4,700.5 4,065.9 1,338.7 Solar — 199.2 — — 164.1 — Property, Plant and Equipment, Gross 11,356.4 11,488.1 3,698.4 10,876.9 10,986.4 3,517.3 Less: Accumulated Depreciation (2,370.6 ) (2,860.3 ) (803.0 ) (2,302.6 ) (2,702.0 ) (772.9 ) Property, Plant and Equipment, Net 8,985.8 8,627.8 2,895.4 8,574.3 8,284.4 2,744.4 Construction Work in Progress 470.8 636.4 136.6 335.4 510.3 135.7 Total Property, Plant and Equipment, Net $ 9,456.6 $ 9,264.2 $ 3,032.0 $ 8,909.7 $ 8,794.7 $ 2,880.1 (1) These assets are primarily comprised of building improvements, computer software, hardware and equipment at Eversource Service. In the second quarter of 2019, Eversource recorded an impairment charge for the NPT project costs, which had been recorded within Construction Work in Progress and also the Transmission - Electric asset category. For further information regarding the impairment of NPT, see Note 1C, "Summary of Significant Accounting Policies - Impairment of Northern Pass Transmission," to the financial statements.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS The electric and natural gas companies purchase and procure energy and energy-related products, which are subject to price volatility, for their customers. The costs associated with supplying energy to customers are recoverable from customers in future rates. These regulated companies manage the risks associated with the price volatility of energy and energy-related products through the use of derivative and non-derivative contracts. Many of the derivative contracts meet the definition of, and are designated as, normal and qualify for accrual accounting under the applicable accounting guidance. The costs and benefits of derivative contracts that meet the definition of normal are recognized in Operating Expenses on the statements of income, as applicable, as electricity or natural gas is delivered. Derivative contracts that are not designated as normal are recorded at fair value as current or long-term Derivative Assets or Derivative Liabilities on the balance sheets. For the electric and natural gas companies, regulatory assets or regulatory liabilities are recorded to offset the fair values of derivatives, as contract settlement amounts are recovered from, or refunded to, customers in their respective energy supply rates. The gross fair values of derivative assets and liabilities with the same counterparty are offset and reported as net Derivative Assets or Derivative Liabilities, with current and long-term portions, on the balance sheets. The following table presents the gross fair values of contracts, categorized by risk type, and the net amounts recorded as current or long-term derivative assets or liabilities: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Fair Value Hierarchy Commodity Supply and Price Risk Management Netting (1) Net Amount Recorded as a Derivative Commodity Supply and Price Risk Netting (1) Net Amount Recorded as a Derivative Current Derivative Assets: CL&P Level 3 $ 11.6 $ (0.3 ) $ 11.3 $ 9.6 $ (3.4 ) $ 6.2 Other Level 2 — — — 1.5 (0.9 ) 0.6 Long-Term Derivative Assets: CL&P Level 3 70.9 (2.2 ) 68.7 74.2 (2.3 ) 71.9 Current Derivative Liabilities: CL&P Level 3 (64.6 ) — (64.6 ) (55.1 ) — (55.1 ) Other Level 2 (3.5 ) 0.2 (3.3 ) — — — Long-Term Derivative Liabilities: CL&P Level 3 (357.7 ) — (357.7 ) (379.5 ) — (379.5 ) Other Level 2 (0.2 ) — (0.2 ) — — — (1) Amounts represent derivative assets and liabilities that Eversource elected to record net on the balance sheets. These amounts are subject to master netting agreements or similar agreements for which the right of offset exists. For further information on the fair value of derivative contracts, see Note 1E, "Summary of Significant Accounting Policies - Fair Value Measurements," to the financial statements. Derivative Contracts at Fair Value with Offsetting Regulatory Amounts Commodity Supply and Price Risk Management : As required by regulation, CL&P, along with UI, has capacity-related contracts with generation facilities. CL&P has a sharing agreement with UI, with 80 percent of the costs or benefits of each contract borne by or allocated to CL&P and 20 percent borne by or allocated to UI. The combined capacities of these contracts as of September 30, 2019 and December 31, 2018 , were 679 MW and 787 MW, respectively. The capacity contracts extend through 2026 and obligate both CL&P and UI to make or receive payments on a monthly basis to or from the generation facilities based on the difference between a set capacity price and the capacity market price received in the ISO-NE capacity markets. In addition, CL&P has a contract to purchase 0.1 million MWh of energy per year through 2020. As of September 30, 2019 and December 31, 2018 , Eversource had New York Mercantile Exchange ("NYMEX") financial contracts for natural gas futures in order to reduce variability associated with the price of 11.6 million and 12.5 million MMBtu of natural gas, respectively. For the three months ended September 30, 2019 and 2018 , there were losses of $9.2 million and gains of $1.6 million , respectively, deferred as regulatory costs, which reflect the change in fair value associated with Eversource's derivative contracts. For the nine months ended September 30, 2019 and 2018 , there were losses of $19.5 million and $25.8 million , respectively. Fair Value Measurements of Derivative Instruments Derivative contracts classified as Level 2 in the fair value hierarchy relate to the financial contracts for natural gas futures. Prices are obtained from broker quotes and are based on actual market activity. The contracts are valued using NYMEX natural gas prices. Valuations of these contracts also incorporate discount rates using the yield curve approach. The fair value of derivative contracts classified as Level 3 utilizes significant unobservable inputs. The fair value is modeled using income techniques, such as discounted cash flow valuations adjusted for assumptions related to exit price. Significant observable inputs for valuations of these contracts include energy and energy-related product prices in future years for which quoted prices in an active market exist. Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The future power and capacity prices for periods that are not quoted in an active market or established at auction are based on available market data and are escalated based on estimates of inflation in order to address the full term of the contract. Valuations of derivative contracts using a discounted cash flow methodology include assumptions regarding the timing and likelihood of scheduled payments and also reflect non-performance risk, including credit, using the default probability approach based on the counterparty's credit rating for assets and the Company's credit rating for liabilities. Valuations incorporate estimates of premiums or discounts that would be required by a market participant to arrive at an exit price, using historical market transactions adjusted for the terms of the contract. The following is a summary of Level 3 derivative contracts and the range of the significant unobservable inputs utilized in the valuations over the duration of the contracts: As of September 30, 2019 As of December 31, 2018 CL&P Range Period Covered Range Period Covered Capacity Prices $ 3.01 — 7.34 per kW-Month 2023 - 2026 $ 4.30 — 7.44 per kW-Month 2022 - 2026 Forward Reserve 0.80 — 1.90 per kW-Month 2019 - 2024 0.75 — 1.78 per kW-Month 2019 - 2024 Exit price premiums of 2.6 percent through 14.1 percent are also applied to these contracts and reflect the uncertainty and illiquidity premiums that would be required based on the most recent market activity available for similar type contracts. Significant increases or decreases in future capacity or forward reserve prices in isolation would decrease or increase, respectively, the fair value of the derivative liability. Any increases in risk premiums would increase the fair value of the derivative liability. Changes in these fair values are recorded as a regulatory asset or liability and do not impact net income. Valuations using significant unobservable inputs: The following table presents changes in the Level 3 category of derivative assets and derivative liabilities measured at fair value on a recurring basis. The derivative assets and liabilities are presented on a net basis. CL&P For the Three Months Ended September 30, For the Nine Months Ended September 30, (Millions of Dollars) 2019 2018 2019 2018 Derivatives, Net: Fair Value as of Beginning of Period $ (345.4 ) $ (369.3 ) $ (356.5 ) $ (362.3 ) Net Realized/Unrealized (Losses)/Gains Included in Regulatory Assets (8.5 ) 1.2 (16.4 ) (27.0 ) Settlements 11.6 8.2 30.6 29.4 Fair Value as of End of Period $ (342.3 ) $ (359.9 ) $ (342.3 ) $ (359.9 )

MARKETABLE SECURITIES

MARKETABLE SECURITIES	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
MARKETABLE SECURITIES	MARKETABLE SECURITIES Eversource holds marketable securities that are primarily used to fund certain non-qualified executive benefits. The trusts that hold marketable securities are not subject to regulatory oversight by state or federal agencies. CYAPC and YAEC maintain legally restricted trusts, each of which holds marketable securities, to fund the spent nuclear fuel removal obligations of their nuclear fuel storage facilities. Equity Securities: Unrealized gains and losses on equity securities held in Eversource's non-qualified executive benefit trust are recorded in Other Income, Net on the statements of income. The fair value of these equity securities as of September 30, 2019 and December 31, 2018 was $43.4 million and $44.0 million , respectively. For each of the three months ended September 30, 2019 and 2018 , there were unrealized gains of $2.4 million , recorded in Other Income, Net related to these equity securities. For the nine months ended September 30, 2019 and 2018 , there were unrealized gains of $5.7 million and $2.6 million , respectively. Eversource's equity securities also include CYAPC's and YAEC's marketable securities held in spent nuclear fuel trusts, which had fair values of $163.7 million and $200.0 million as of September 30, 2019 and December 31, 2018 , respectively. Unrealized gains and losses for these spent nuclear fuel trusts are subject to regulatory accounting treatment and are recorded in Marketable Securities with the corresponding offset to Other Long-Term Liabilities on the balance sheets, with no impact on the statements of income. Available-for-Sale Debt Securities: The following is a summary of the available-for-sale debt securities, which are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of September 30, 2019 As of December 31, 2018 Eversource (Millions of Dollars) Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Debt Securities $ 203.0 $ 8.9 $ (0.1 ) $ 211.8 $ 190.0 $ 0.4 $ (4.0 ) $ 186.4 Eversource's debt securities include CYAPC's and YAEC's marketable securities held in spent nuclear fuel trusts in the amounts of $174.7 million and $143.9 million as of September 30, 2019 and December 31, 2018 , respectively. Unrealized gains and losses on available-for-sale debt securities held in Eversource's non-qualified benefit trust are recorded in Accumulated Other Comprehensive Income. There have been no significant unrealized losses, other-than-temporary impairments, or credit losses for the three and nine months ended September 30, 2019 and 2018 . Factors considered in determining whether a credit loss exists include the duration and severity of the impairment, adverse conditions specifically affecting the issuer, and the payment history, ratings and rating changes of the security. For asset-backed debt securities, underlying collateral and expected future cash flows are also evaluated. As of September 30, 2019 , the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Cost Fair Value Less than one year (1) $ 28.6 $ 28.5 One to five years 49.8 51.2 Six to ten years 30.0 31.9 Greater than ten years 94.6 100.2 Total Debt Securities $ 203.0 $ 211.8 (1) Amounts in the Less than one year category include securities in the CYAPC and YAEC spent nuclear fuel trusts, which are restricted and are classified in long-term Marketable Securities on the balance sheets. Realized Gains and Losses: Realized gains and losses are recorded in Other Income, Net for Eversource's benefit trust and are offset in Other Long-Term Liabilities for CYAPC and YAEC. Eversource utilizes the specific identification basis method for the Eversource non-qualified benefit trust, and the average cost basis method for the CYAPC and YAEC spent nuclear fuel trusts to compute the realized gains and losses on the sale of marketable securities. Fair Value Measurements: The following table presents the marketable securities recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Eversource (Millions of Dollars) As of September 30, 2019 As of December 31, 2018 Level 1: Mutual Funds and Equities $ 207.1 $ 244.0 Money Market Funds 19.6 25.9 Total Level 1 $ 226.7 $ 269.9 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 95.2 $ 79.6 Corporate Debt Securities 49.5 39.5 Asset-Backed Debt Securities 13.1 14.0 Municipal Bonds 25.6 19.2 Other Fixed Income Securities 8.8 8.2 Total Level 2 $ 192.2 $ 160.5 Total Marketable Securities $ 418.9 $ 430.4 U.S. government issued debt securities are valued using market approaches that incorporate transactions for the same or similar bonds and adjustments for yields and maturity dates. Corporate debt securities are valued using a market approach, utilizing recent trades of the same or similar instruments and also incorporating yield curves, credit spreads and specific bond terms and conditions. Asset-backed debt securities include collateralized mortgage obligations, commercial mortgage backed securities, and securities collateralized by auto loans, credit card loans or receivables. Asset-backed debt securities are valued using recent trades of similar instruments, prepayment assumptions, yield curves, issuance and maturity dates, and tranche information. Municipal bonds are valued using a market approach that incorporates reported trades and benchmark yields. Other fixed income securities are valued using pricing models, quoted prices of securities with similar characteristics, and discounted cash flows.

SHORT-TERM AND LONG-TERM DEBT

SHORT-TERM AND LONG-TERM DEBT	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
SHORT-TERM AND LONG-TERM DEBT	SHORT-TERM AND LONG-TERM DEBT Short-Term Debt - Commercial Paper Programs and Credit Agreements : Eversource parent has a $1.45 billion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. Eversource parent, CL&P, PSNH, NSTAR Gas, Yankee Gas and Aquarion Water Company of Connecticut are also parties to a five -year $1.45 billion revolving credit facility, which terminates on December 8, 2023 . The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. NSTAR Electric has a $650 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. NSTAR Electric is also a party to a five -year $650 million revolving credit facility, which terminates on December 8, 2023 . The revolving credit facility serves to backstop NSTAR Electric's $650 million commercial paper program. The amount of borrowings outstanding and available under the commercial paper programs were as follows: Borrowings Outstanding as of Available Borrowing Capacity as of Weighted-Average Interest Rate as of September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 (Millions of Dollars) Eversource Parent Commercial Paper Program $ 684.5 $ 631.5 $ 765.5 $ 818.5 2.25 % 2.77 % NSTAR Electric Commercial Paper Program 28.0 278.5 622.0 371.5 1.98 % 2.50 % There were no borrowings outstanding on either the Eversource parent or NSTAR Electric revolving credit facilities as of September 30, 2019 or December 31, 2018 . Amounts outstanding under the commercial paper programs and revolving credit facility are included in Notes Payable and are classified in current liabilities on the Eversource and NSTAR Electric balance sheets as all borrowings are outstanding for no more than 364 days at one time. We expect the future operating cash flows of Eversource, CL&P, NSTAR Electric and PSNH, along with our existing borrowing availability and access to both debt and equity markets, will be sufficient to meet any working capital and future operating requirements, and capital investment forecasted opportunities. Intercompany Borrowings: Eversource parent uses its available capital resources to provide loans to its subsidiaries to assist them in meeting their short-term borrowing needs. In addition, growth in Eversource's key business initiatives requires cash infusion to those subsidiaries. Eversource parent records intercompany interest income from its loans to subsidiaries, which is eliminated in consolidation. Intercompany loans from Eversource parent to its subsidiaries are eliminated in consolidation on Eversource's balance sheets. As of September 30, 2019 , there were intercompany loans from Eversource parent to CL&P of $173.1 million , to PSNH of $42.1 million , and to Harbor Electric Energy Company ("HEEC"), a wholly-owned subsidiary of NSTAR Electric, of $48.7 million . As of December 31, 2018 , there were intercompany loans from Eversource parent to PSNH of $57.0 million . Intercompany loans from Eversource parent are included in Notes Payable to Eversource Parent and are classified in current liabilities on the respective subsidiary's balance sheets. Long-Term Debt Issuance Authorization: On April 26, 2019, the NHPUC approved PSNH’s request for authorization to issue up to $300 million in long-term debt through December 31, 2019. On August 14, 2019, PURA approved CL&P's request for authorization to issue up to $675 million in long-term debt through December 31, 2022. Long-Term Debt: The following table summarizes long-term debt issuances and repayments: (Millions of Dollars) Issue Date Issuance/(Repayment) Maturity Date Use of Proceeds for Issuance/ CL&P: 4.00% 2018 Series A First Mortgage Bonds (1) April 2019 $ 300.0 April 2048 Paid short-term borrowings that were used to pay long-term debt that matured on February 1, 2019 and fund capital expenditures and working capital 3.20% 2017 Series A First Mortgage Bonds (2) September 2019 200.0 March 2027 Paid short-term borrowings and fund capital expenditures and working capital 5.50% 2009 Series A First Mortgage Bonds February 2009 (250.0 ) February 2019 Paid at maturity on February 1, 2019 NSTAR Electric: 3.25% 2019 Debentures May 2019 400.0 May 2029 Paid short-term borrowings that were used to fund investments in eligible green expenditures PSNH: 3.60% 2019 Series T First Mortgage Bonds June 2019 300.0 July 2049 Paid long-term debt due to mature in December 2019, paid short-term borrowings and fund capital expenditures and working capital Other: NSTAR Gas 3.74% Series Q First Mortgage Bonds July 2019 75.0 August 2049 Paid short-term borrowings and fund capital expenditures and working capital Yankee Gas 2.23% Series P First Mortgage Bonds September 2019 100.0 October 2024 Paid long-term debt due to mature in November 2019, paid short-term borrowings and fund capital expenditures and working capital Yankee Gas 3.30% Series Q First Mortgage Bonds September 2019 100.0 October 2049 Paid long-term debt due to mature in November 2019, paid short-term borrowings and fund capital expenditures and working capital (1) These bonds are part of the same series issued by CL&P in March 2018. The aggregate outstanding principal amount of these bonds is now $800 million . (2) These bonds are part of the same series issued by CL&P in March 2017. The aggregate outstanding principal amount of these bonds is now $500 million .

RATE REDUCTION BONDS AND VARIAB

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES	9 Months Ended
	Sep. 30, 2019
Rate Reduction Bonds and Variable Interest Entity [Abstract]
RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES	RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES Rate Reduction Bonds: On May 8, 2018, PSNH Funding, a wholly-owned subsidiary of PSNH, issued $635.7 million of securitized RRBs in multiple tranches with a weighted average interest rate of 3.66 percent , and final maturity dates ranging from 2026 to 2035. The RRBs are expected to be repaid by February 1, 2033. RRB payments consist of principal and interest and will be paid semi-annually, beginning on February 1, 2019. The RRBs were issued pursuant to a finance order issued by the NHPUC on January 30, 2018 to recover remaining costs resulting from the divestiture of PSNH’s generation assets. PSNH Funding is considered a VIE primarily because the equity capitalization is insufficient to support its operations. PSNH has the power to direct the significant activities of the VIE and is most closely associated with the VIE as compared to other interest holders. Therefore, PSNH is considered the primary beneficiary and consolidates PSNH Funding in its consolidated financial statements. The following tables summarize the impact of PSNH Funding on PSNH's balance sheets and income statements: (Millions of Dollars) Balance Sheet: As of September 30, 2019 As of December 31, 2018 Restricted Cash - Current Portion (included in Prepayments and Other Current Assets) $ 18.5 $ 47.5 Restricted Cash - Long-Term Portion (included in Other Long-Term Assets) 3.2 3.2 Securitized Stranded Costs (included in Regulatory Assets) 576.1 608.4 Other Regulatory Liabilities (included in Regulatory Liabilities) 7.7 5.8 Accrued Interest (included in Other Current Liabilities) 3.4 14.4 Rate Reduction Bonds - Current Portion 43.2 52.3 Rate Reduction Bonds - Long-Term Portion 540.1 583.3 (Millions of Dollars) For the Three Months Ended For the Nine Months Ended Income Statement: September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net) $ 10.8 $ 10.2 $ 32.2 $ 17.1 Interest Expense on RRB Principal (included in Interest Expense) 5.2 6.0 15.9 8.8

PENSION BENEFITS AND POSTRETIRE

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION	9 Months Ended
	Sep. 30, 2019
Postemployment Benefits [Abstract]
PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION	PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION Eversource provides defined benefit retirement plans ("Pension Plans") that cover eligible employees. In addition to the Pension Plans, Eversource maintains non-qualified defined benefit retirement plans ("SERP Plans"), which provide benefits in excess of Internal Revenue Code limitations to eligible participants consisting of current and retired employees. Eversource also provides defined benefit postretirement plans ("PBOP Plans") that provide life insurance and a health reimbursement arrangement created for the purpose of reimbursing retirees and dependents for health insurance premiums and certain medical expenses to eligible employees that meet certain age and service eligibility requirements. We contributed $112.5 million and $183.2 million to the Pension Plans for the nine months ended September 30, 2019 and 2018 , respectively, and $7.9 million and $5.7 million to the PBOP Plans for the nine months ended September 30, 2019 and 2018 , respectively. The components of net periodic benefit expense/(income) for the Pension, SERP and PBOP Plans, prior to amounts capitalized as Property, Plant and Equipment or deferred as regulatory assets for future recovery, are shown below. The service cost component of net periodic benefit expense, less the capitalized portion, is included in Operations and Maintenance expense on the statements of income. The remaining components of net periodic benefit expense/(income), less the deferred portion, are included in Other Income, Net on the statements of income. Pension, SERP and PBOP expense reflected in the statements of cash flows for CL&P, NSTAR Electric and PSNH does not include the intercompany allocations or the corresponding capitalized and deferred portion, as these amounts are cash settled on a short-term basis. Pension and SERP For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 16.2 $ 4.4 $ 3.6 $ 1.5 $ 20.9 $ 5.2 $ 4.3 $ 2.7 Interest Cost 54.8 11.4 12.3 6.0 49.2 10.5 10.9 5.5 Expected Return on Pension Plan Assets (91.6 ) (18.1 ) (24.2 ) (10.1 ) (97.8 ) (19.4 ) (26.6 ) (10.8 ) Actuarial Loss 35.6 6.3 11.8 2.3 35.7 7.1 10.1 3.3 Prior Service Cost 0.3 — — — 2.0 0.2 0.1 0.1 Total Net Periodic Benefit Expense/(Income) $ 15.3 $ 4.0 $ 3.5 $ (0.3 ) $ 10.0 $ 3.6 $ (1.2 ) $ 0.8 Intercompany Allocations N/A $ 2.0 $ 1.9 $ 0.5 N/A $ 1.5 $ 1.6 $ 0.5 Pension and SERP For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 51.6 $ 13.6 $ 11.0 $ 5.6 $ 64.2 $ 16.2 $ 13.1 $ 8.4 Interest Cost 163.8 34.4 36.6 18.2 147.1 31.4 32.6 16.4 Expected Return on Pension Plan Assets (275.4 ) (55.1 ) (72.9 ) (30.6 ) (293.8 ) (59.7 ) (78.3 ) (32.6 ) Actuarial Loss 107.9 20.6 33.1 8.2 107.6 21.9 31.0 9.8 Prior Service Cost 0.9 — 0.2 — 6.0 0.8 0.2 0.2 Total Net Periodic Benefit Expense/(Income) $ 48.8 $ 13.5 $ 8.0 $ 1.4 $ 31.1 $ 10.6 $ (1.4 ) $ 2.2 Intercompany Allocations N/A $ 6.5 $ 6.1 $ 1.8 N/A $ 4.5 $ 4.8 $ 1.4 PBOP For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 2.0 $ 0.3 $ 0.4 $ 0.2 $ 2.5 $ 0.4 $ 0.5 $ 0.3 Interest Cost 8.1 1.6 2.4 0.8 7.7 1.5 2.2 0.9 Expected Return on Plan Assets (16.7 ) (2.2 ) (7.5 ) (1.3 ) (18.2 ) (2.6 ) (8.1 ) (1.5 ) Actuarial Loss 2.1 0.3 0.8 0.1 2.6 0.4 0.5 0.2 Prior Service Cost/(Credit) (5.8 ) 0.2 (4.2 ) 0.1 (6.0 ) 0.3 (4.3 ) 0.1 Total Net Periodic Benefit Expense/(Income) $ (10.3 ) $ 0.2 $ (8.1 ) $ (0.1 ) $ (11.4 ) $ — $ (9.2 ) $ — Intercompany Allocations N/A $ (0.2 ) $ (0.3 ) $ (0.1 ) N/A $ (0.3 ) $ (0.3 ) $ (0.1 ) PBOP For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 5.9 $ 1.1 $ 1.3 $ 0.5 $ 7.5 $ 1.4 $ 1.6 $ 0.9 Interest Cost 24.5 4.7 7.1 2.5 23.0 4.4 6.5 2.5 Expected Return on Plan Assets (50.1 ) (6.9 ) (22.6 ) (4.0 ) (54.2 ) (7.8 ) (24.4 ) (4.5 ) Actuarial Loss 6.2 1.0 2.5 0.3 7.7 1.2 1.7 0.6 Prior Service Cost/(Credit) (17.6 ) 0.8 (12.7 ) 0.3 (17.6 ) 0.8 (12.7 ) 0.4 Total Net Periodic Benefit Expense/(Income) $ (31.1 ) $ 0.7 $ (24.4 ) $ (0.4 ) $ (33.6 ) $ — $ (27.3 ) $ (0.1 ) Intercompany Allocations N/A $ (0.6 ) $ (0.9 ) $ (0.3 ) N/A $ (0.8 ) $ (1.0 ) $ (0.3 )

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES A. Environmental Matters Eversource, CL&P, NSTAR Electric and PSNH are subject to environmental laws and regulations intended to mitigate or remove the effect of past operations and improve or maintain the quality of the environment. These laws and regulations require the removal or the remedy of the effect on the environment of the disposal or release of certain specified hazardous substances at current and former operating sites. Eversource, CL&P, NSTAR Electric and PSNH have an active environmental auditing and training program and each believes it is substantially in compliance with all enacted laws and regulations. The number of environmental sites and related reserves for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: As of September 30, 2019 As of December 31, 2018 Number of Sites Reserve (in millions) Number of Sites Reserve (in millions) Eversource 58 $ 70.3 60 $ 64.7 CL&P 15 6.0 15 5.4 NSTAR Electric 15 9.5 16 10.9 PSNH 9 5.7 9 5.4 Included in the number of sites and reserve amounts above are former MGP sites that were operated several decades ago and manufactured gas from coal and other processes, which resulted in certain by-products remaining in the environment that may pose a potential risk to human health and the environment, for which Eversource may have potential liability. The reserve balances related to these former MGP sites were $56.4 million and $50.1 million as of September 30, 2019 and December 31, 2018 , respectively, and related primarily to the natural gas business segment. These reserve estimates are subjective in nature as they take into consideration several different remediation options at each specific site. The reliability and precision of these estimates can be affected by several factors, including new information concerning either the level of contamination at the site, the extent of Eversource's, CL&P's, NSTAR Electric's and PSNH's responsibility for remediation or the extent of remediation required, recently enacted laws and regulations or changes in cost estimates due to certain economic factors. It is possible that new information or future developments could require a reassessment of the potential exposure to required environmental remediation. As this information becomes available, management will continue to assess the potential exposure and adjust the reserves accordingly. B. Long-Term Contractual Arrangements On December 28, 2018 , under Public Act 17-3, "An Act Concerning Zero Carbon Procurement," DEEP selected the Millstone Nuclear Power Station generation facility and Seabrook Nuclear Power Plant, along with smaller generation facilities, in DEEP’s zero-carbon request for proposal. CL&P and UI were directed by DEEP to enter into ten -year contracts to purchase a combined total of approximately 9 million MWh annually from the Millstone generation facility. On March 15, 2019 , CL&P and UI each signed a ten -year contract with the owner of Millstone Nuclear Power Station in order to purchase a combined amount of approximately 50 percent of the facility's output (approximately 40 percent by CL&P). The Millstone Nuclear Power Station has a 2,112 MW nameplate capacity. PURA approved the contracts on September 18, 2019. The significant output of the Millstone generation facility, the contract period, and the pricing will result in estimated annual contractual commitments of approximately $360 million over the ten -year contract term. CL&P plans to sell the energy purchased under this contract into the market and use the proceeds from these energy sales to offset the contract costs. As the net costs under this contract will be recovered from customers in future rates, the contract will not have an impact on the net income of CL&P. Energy deliveries under this contract began in October 2019, for which payments will begin in November 2019. Contracts with other suppliers selected by DEEP are being reviewed by PURA. C. Guarantees and Indemnifications In the normal course of business, Eversource parent provides credit assurances on behalf of its subsidiaries, including CL&P, NSTAR Electric and PSNH, in the form of guarantees. Eversource parent issued a guaranty on behalf of its subsidiary, NPT, under which, beginning at the time the Northern Pass Transmission line would go into commercial operation, Eversource parent would guarantee the financial obligations of NPT under the TSA with HQ in an amount not to exceed $25 million . Eversource parent's obligations under the guaranty expire upon the full, final and indefeasible payment of the guaranteed obligations. In the second quarter of 2019, Eversource concluded that construction of the NPT project was no longer probable. F or further information regarding the impairment of NPT, see Note 1C, "Summary of Significant Accounting Policies - Impairment of Northern Pass Transmission," to the financial statements. While this guaranty is currently outstanding, it is expected to be extinguished in connection with the final dissolution of NPT. Management does not anticipate a material impact to net income or cash flows as a result of these various guarantees and indemnifications. The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries to external parties, as of September 30, 2019 : Company Description Maximum Exposure (in millions) Expiration Dates On behalf of subsidiaries: Various Surety Bonds (1) $ 34.3 2019 - 2021 Rocky River Realty Company and Eversource Service Lease Payments for Real Estate 6.8 2024 Bay State Wind Real Estate Purchase 2.5 2020 (1) Surety bond expiration dates reflect termination dates, the majority of which will be renewed or extended. Certain surety bonds contain credit ratings triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource parent are downgraded. On October 25, 2019, Eversource parent issued a guaranty on behalf of its 50 percent -owned joint venture subsidiary, Sunrise Wind LLC, whereby Eversource parent will guaranty Sunrise Wind LLC’s performance of certain obligations, in an amount not to exceed $15.4 million , under the Offshore Wind Renewable Energy Certificate Purchase and Sale Agreement (the "Agreement"). The Agreement was executed on October 23, 2019, by and between the New York State Energy Research and Development Authority ("NYSERDA") and Sunrise Wind LLC. Obligations of Eversource parent under the guaranty expire at such time as the guaranteed obligations have been fully performed. D. Spent Nuclear Fuel Obligations - Yankee Companies CL&P, NSTAR Electric and PSNH have plant closure and fuel storage cost obligations to the Yankee Companies, which have each completed the physical decommissioning of their respective nuclear facilities and are now engaged in the long-term storage of their spent fuel. The Yankee Companies fund these costs through litigation proceeds received from the DOE and, to the extent necessary, through wholesale, FERC-approved rates charged under power purchase agreements with several New England utilities, including CL&P, NSTAR Electric and PSNH. CL&P, NSTAR Electric and PSNH, in turn recover these costs from their customers through state regulatory commission-approved retail rates. The Yankee Companies collect amounts that management believes are adequate to recover the remaining plant closure and fuel storage cost estimates for the respective plants. Management believes CL&P and NSTAR Electric will recover their shares of these obligations from their customers. PSNH has recovered its total share of these costs from its customers. Spent Nuclear Fuel Litigation: The Yankee Companies have filed complaints against the DOE in the Court of Federal Claims seeking monetary damages resulting from the DOE's failure to provide for a permanent facility to store spent nuclear fuel pursuant to the terms of the 1983 spent fuel and high level waste disposal contracts between the Yankee Companies and the DOE. The court had previously awarded the Yankee Companies damages for Phase I, II and III of litigation resulting from the DOE's failure to meet its contractual obligations. These Phases covered damages incurred in the years 1998 through 2012, and the awarded damages have been received by the Yankee Companies with certain amounts of the damages refunded to their customers. DOE Phase IV Damages - On May 22, 2017, each of the Yankee Companies filed subsequent lawsuits against the DOE in the Court of Federal Claims. The Yankee Companies sought monetary damages totaling $104.4 million for CYAPC, YAEC and MYAPC, resulting from the DOE's failure to begin accepting spent nuclear fuel for disposal covering the years from 2013 to 2016 (“DOE Phase IV”). On February 21, 2019, the Yankee Companies received a partial summary judgment and partial final judgment in their favor for the undisputed amount of monetary damages of $103.2 million . The court awarded CYAPC, YAEC and MYAPC damages of $40.7 million , $28.1 million and $34.4 million , respectively. The DOE did not appeal the court's judgment and the decision became final on April 23, 2019. On June 12, 2019, CYAPC and YAEC received damages of $40.7 million and $28.1 million , respectively, which were recorded as restricted cash within Other Long-Term Assets on the Eversource consolidated balance sheet as of September 30, 2019. On June 12, 2019, the court accepted an offer of judgment in the amount of $0.5 million to settle the disputed amount of approximately $1 million in Phase IV contested damages. The Yankee Companies received the $0.5 million payment in July 2019. In September 2019, the Yankee Companies made a required informational filing with FERC as to the use of proceeds. FERC approval and payment to the Eversource utilities (CL&P, NSTAR Electric and PSNH) is expected in the fourth quarter of 2019. At this time, the damages are primarily expected to be used by the Yankee Companies to fund remaining fuel storage obligations, and management does not expect significant amounts to be refunded to the utilities. The utilities will ultimately refund any amounts received to utility customers. E. FERC ROE Complaints Four separate complaints have been filed at the FERC by combinations of New England state attorneys general, state regulatory commissions, consumer advocates, consumer groups, municipal parties and other parties (collectively the "Complainants"). In each of the first three complaints, filed on October 1, 2011, December 27, 2012, and July 31, 2014, respectively, the Complainants challenged the NETOs' base ROE of 11.14 percent that had been utilized since 2005 and sought an order to reduce it prospectively from the date of the final FERC order and for the separate 15 -month complaint periods. In the fourth complaint, filed April 29, 2016, the Complainants challenged the NETOs' base ROE billed of 10.57 percent and the maximum ROE for transmission incentive ("incentive cap") of 11.74 percent , asserting that these ROEs were unjust and unreasonable. The ROE originally billed during the period October 1, 2011 (beginning of the first complaint period) through October 15, 2014 consisted of a base ROE of 11.14 percent and incentives up to 13.1 percent . On October 16, 2014, the FERC set the base ROE at 10.57 percent and the incentive cap at 11.74 percent for the first complaint period. This was also effective for all prospective billings to customers beginning October 16, 2014. This FERC order was vacated on April 14, 2017 by the U.S. Court of Appeals for the D.C. Circuit (the "Court"). All amounts associated with the first complaint period have been refunded, which totaled $38.9 million (pre-tax and excluding interest) at Eversource and reflected both the base ROE and incentive cap prescribed by the FERC order. The refund consisted of $22.4 million for CL&P, $13.7 million for NSTAR Electric and $2.8 million for PSNH. Eversource has recorded a reserve of $39.1 million (pre-tax and excluding interest) for the second complaint period as of September 30, 2019 . This reserve represents the difference between the billed rates during the second complaint period and a 10.57 percent base ROE and 11.74 percent incentive cap. The reserve consisted of $21.4 million for CL&P, $14.6 million for NSTAR Electric and $3.1 million for PSNH as of September 30, 2019 . On October 16, 2018, FERC issued an order on all four complaints describing how it intends to address the issues that were remanded by the Court. FERC proposed a new framework to determine (1) whether an existing ROE is unjust and unreasonable and, if so, (2) how to calculate a replacement ROE. The parties to these proceedings were directed to submit briefs on this new proposed framework and how they would apply the proposed framework in each of the four complaint proceedings. Initial briefs were filed by the NETOs, Complainants and FERC Trial Staff on January 11, 2019 and reply briefs were filed on March 8, 2019. The NETOs' brief was supportive of the overall ROE methodology determined in the October 16, 2018 order provided the FERC does not change the proposed methodology or alter its implementation in a manner that has a material impact on the results. The FERC order included illustrative calculations for the first complaint using FERC's proposed frameworks with financial data from that complaint. Those preliminary calculations indicated that for the first complaint period, for the NETOs that FERC concludes are of average financial risk, (1) a preliminary range of presumptively just and reasonable base ROEs is 9.60 percent to 10.99 percent ; (2) the pre-existing base ROE of 11.14 percent is therefore unjust and unreasonable; (3) the preliminary just and reasonable base ROE is 10.41 percent ; and (4) the preliminary incentive cap on total ROE is 13.08 percent . If the results of these illustrative calculations were included in a final FERC order for each of the complaint periods, then a 10.41 percent base ROE and a 13.08 percent incentive cap would not have a significant impact on our financial statements for all of the complaint periods. Although the order provided illustrative calculations, FERC stated that these calculations are merely preliminary. The FERC’s preliminary calculations are not binding and do not represent what we believe to be the most likely outcome of a final FERC order, as changes to the methodology by FERC are possible as a result of the parties’ arguments and calculations in the briefing process. Until FERC issues a final decision on each of these four complaints, there is significant uncertainty, and at this time, the Company cannot reasonably estimate a range of gain or loss for any of the four complaint proceedings. The October 16, 2018 FERC order or the 2019 briefs did not provide a reasonable basis for a change to the reserve or recognized ROEs for any of the complaint periods. Eversource, CL&P, NSTAR Electric and PSNH currently record revenues at the 10.57 percent base ROE and incentive cap at 11.74 percent established in the October 16, 2014 FERC order. The average impact of a 10 basis point change to the base ROE for each of the 15 -month complaint periods would affect Eversource's after-tax earnings by approximately $3 million . F. Eversource and NSTAR Electric Boston Harbor Civil Action On July 15, 2016, the United States Attorney on behalf of the United States Army Corps of Engineers filed a civil action in the United States District Court for the District of Massachusetts under provisions of the Rivers and Harbors Act of 1899 and the Clean Water Act against NSTAR Electric, HEEC, and the Massachusetts Water Resources Authority (together with NSTAR Electric and HEEC, the "Defendants"). The action alleged that the Defendants failed to comply with certain permitting requirements related to the placement of the HEEC-owned electric distribution cable beneath Boston Harbor. The action sought an order to compel HEEC to comply with cable depth requirements in the United States Army Corps of Engineers' permit or alternatively to remove the electric distribution cable and cease unauthorized work in U.S. waterways. The action also sought civil penalties and other costs. The parties reached a settlement pursuant to which HEEC agreed to install a new 115 kV distribution cable across Boston Harbor to Deer Island, utilizing a different route, and remove portions of the existing cable. Upon installation and completion of the new cable and removal of the portions of the existing cable, all issues surrounding the current permit from the United States Army Corps of Engineers are expected to be resolved, and such litigation is expected to be dismissed with prejudice. Construction of the new distribution cable was completed in August 2019 and removal of the portions of the existing cable is expected to be completed by May of 2020. NSTAR Electric agreed to provide a rate base credit of $17.5 million to the Massachusetts Water Resources Authority for the new cable. This negotiated credit resulted in the initial $17.5 million of construction costs on the new cable being expensed as incurred, all of which was fully expensed in 2018. In connection with the new cable that was placed into service, a corresponding ARO was recognized for approximately $32 million within Other Long-Term Liabilities on the Eversource and NSTAR Electric balance sheets as of September 30, 2019 .

LEASES

LEASES	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
LEASES	LEASES Eversource, including CL&P, NSTAR Electric and PSNH, has entered into lease agreements as a lessee for the use of land, office space, service centers, vehicles, information technology, and equipment. These lease agreements are classified as either finance or operating leases and the liability and right-of-use asset are recognized on the balance sheet at lease commencement. Leases with an initial term of 12 months or less are not recorded on the balance sheet and are recognized as lease expense on a straight-line basis over the lease term. Eversource determines whether or not a contract contains a lease based on whether or not it provides Eversource with the use of a specifically identified asset for a period of time, as well as both the right to direct the use of that asset and receive the significant economic benefits of the asset. Eversource has elected the practical expedient to not separate non-lease components from lease components and instead to account for both as a single lease component, with the exception of the information technology asset class where the lease and non-lease components are separated. The provisions of Eversource, CL&P, NSTAR Electric and PSNH lease agreements contain renewal options. The renewal options range from one year to twenty years . The renewal period is included in the measurement of the lease liability if it is reasonably certain that Eversource will exercise these renewal options. For leases entered into or modified after the January 1, 2019 implementation date, the discount rate utilized for classification and measurement purposes as of the inception date of the lease is based on each company's collateralized incremental interest rate to borrow over a comparable term for an individual lease, as the rate implicit in the lease is not determinable. CL&P and PSNH entered into certain contracts for the purchase of energy that qualify as leases. These contracts do not have minimum lease payments and therefore are not recognized as a lease liability on the balance sheet and are not reflected in the future minimum lease payments table below. Expense related to these contracts are included as variable lease cost in the table below. The expense and long-term obligation for these contracts are included in the annually reported contractual obligations table in Note 12B, "Commitments and Contingencies - Long-Term Contractual Arrangements," of the Eversource 2018 Form 10-K. The components of lease cost, prior to amounts capitalized, are as follows: For the Three Months Ended September 30, 2019 For the Nine Months Ended September 30, 2019 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Financing Lease Cost: Amortization of Right-of-use-Assets $ 0.4 $ 0.2 $ 0.1 $ — $ 1.1 $ 0.6 $ 0.1 $ 0.1 Interest on Lease Liabilities 0.3 0.1 0.1 — 1.0 0.4 0.4 — Total Finance Lease Cost 0.7 0.3 0.2 — 2.1 1.0 0.5 0.1 Operating Lease Cost 2.9 0.1 0.5 — 8.9 0.3 1.3 0.1 Variable Lease Cost 15.3 3.6 — 11.7 46.4 10.1 — 36.3 Total Lease Cost $ 18.9 $ 4.0 $ 0.7 $ 11.7 $ 57.4 $ 11.4 $ 1.8 $ 36.5 Operating lease cost, less the capitalized portion, is included in Operations and Maintenance (or Purchased Power, Fuel and Transmission expense for transmission segment leases) on the statements of income. Amortization of finance lease assets is included in Depreciation on the statements of income. Interest expense on finance leases is included in Interest Expense, Net on the statements of income. Supplemental balance sheet information related to leases is as follows: As of September 30, 2019 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Operating Leases: Operating Lease Right-of-use-Assets, Net Other Long-Term Assets $ 52.3 $ 0.9 $ 24.2 $ 0.4 Operating Lease Liabilities Operating Lease Liabilities - Current Portion Other Current Liabilities $ 8.9 $ 0.5 $ 0.6 $ — Operating Lease Liabilities - Long-Term Other Long-Term Liabilities 43.4 0.4 23.6 0.4 Total Operating Lease Liabilities $ 52.3 $ 0.9 $ 24.2 $ 0.4 Finance Leases: Finance Lease Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 8.8 $ 2.2 $ 3.4 $ 0.9 Finance Lease Liabilities Finance Lease Liabilities - Current Portion Other Current Liabilities $ 2.3 $ 1.6 $ — $ 0.1 Finance Lease Liabilities - Long-Term Other Long-Term Liabilities 8.7 1.8 4.4 0.8 Total Finance Lease Liabilities $ 11.0 $ 3.4 $ 4.4 $ 0.9 The finance lease payments that NSTAR Electric will make over the next twelve months are entirely interest-related, due to escalating payments. As such, none of the finance lease payments over the next twelve months will reduce the finance lease liability. Other information related to leases is as follows (in millions of dollars, unless otherwise noted): Eversource CL&P NSTAR Electric PSNH As of September 30, 2019 Weighted-Average Remaining Lease Term (Years): Operating Leases 12 2 20 9 Financing Leases 11 2 22 9 Weighted-Average Discount Rate (Percentage): Operating Leases 3.9 % 2.5 % 4.1 % 3.7 % Financing Leases 4.2 % 10.5 % 2.9 % 3.5 % For the Three Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 2.9 $ 0.1 $ 0.5 $ — Operating Cash Flows from Finance Leases 0.3 0.1 0.1 — Financing Cash Flows from Finance Leases 0.5 0.4 — — Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.9 0.8 — — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities — — — — For the Nine Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 8.7 $ 0.3 $ 1.2 $ 0.1 Operating Cash Flows from Finance Leases 1.0 0.4 0.4 — Financing Cash Flows from Finance Leases 1.5 1.0 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.6 1.0 — 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 1.3 — — — Future minimum lease payments, excluding variable costs, under long-term leases, as of September 30, 2019 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH October 1, 2019 through December 31, 2019 $ 2.6 $ 0.1 $ 0.3 $ — $ 0.9 $ 0.5 $ 0.1 $ — Year Ending December 31, 2020 10.1 0.5 1.6 0.1 3.4 2.0 0.5 0.1 2021 8.9 0.2 1.6 0.1 2.9 1.5 0.5 0.1 2022 7.4 — 1.6 0.1 1.5 — 0.6 0.1 2023 4.9 — 1.6 — 0.7 — 0.6 0.1 2024 2.8 — 1.6 — 0.7 — 0.6 0.1 Thereafter 28.9 0.1 28.7 0.2 13.3 — 12.8 0.5 Future lease payments 65.6 0.9 37.0 0.5 23.4 4.0 15.7 1.0 Less amount representing interest 13.3 — 12.8 0.1 12.4 0.6 11.3 0.1 Present value of future minimum lease payments $ 52.3 $ 0.9 $ 24.2 $ 0.4 $ 11.0 $ 3.4 $ 4.4 $ 0.9 At December 31, 2018, future minimum rental payments, excluding executory costs, such as property taxes, state use taxes, insurance, and maintenance were as follows: Operating Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 11.5 $ 1.5 $ 7.2 $ 0.5 2020 9.8 1.4 6.0 0.4 2021 8.7 1.2 5.3 0.4 2022 7.2 1.1 4.4 0.4 2023 4.7 0.5 3.1 0.2 Thereafter 32.7 0.2 29.5 0.3 Future minimum lease payments $ 74.6 $ 5.9 $ 55.5 $ 2.2 Capital Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 3.4 $ 2.0 $ 0.5 $ 0.1 2020 3.4 2.0 0.5 0.1 2021 2.9 1.5 0.5 0.1 2022 1.5 — 0.6 0.1 2023 0.7 — 0.6 0.1 Thereafter 13.9 — 13.4 0.5 Future minimum lease payments 25.8 5.5 16.1 1.0 Less amount representing interest 13.8 1.0 12.4 0.1 Present value of future minimum lease payments $ 12.0 $ 4.5 $ 3.7 $ 0.9
LEASES	LEASES Eversource, including CL&P, NSTAR Electric and PSNH, has entered into lease agreements as a lessee for the use of land, office space, service centers, vehicles, information technology, and equipment. These lease agreements are classified as either finance or operating leases and the liability and right-of-use asset are recognized on the balance sheet at lease commencement. Leases with an initial term of 12 months or less are not recorded on the balance sheet and are recognized as lease expense on a straight-line basis over the lease term. Eversource determines whether or not a contract contains a lease based on whether or not it provides Eversource with the use of a specifically identified asset for a period of time, as well as both the right to direct the use of that asset and receive the significant economic benefits of the asset. Eversource has elected the practical expedient to not separate non-lease components from lease components and instead to account for both as a single lease component, with the exception of the information technology asset class where the lease and non-lease components are separated. The provisions of Eversource, CL&P, NSTAR Electric and PSNH lease agreements contain renewal options. The renewal options range from one year to twenty years . The renewal period is included in the measurement of the lease liability if it is reasonably certain that Eversource will exercise these renewal options. For leases entered into or modified after the January 1, 2019 implementation date, the discount rate utilized for classification and measurement purposes as of the inception date of the lease is based on each company's collateralized incremental interest rate to borrow over a comparable term for an individual lease, as the rate implicit in the lease is not determinable. CL&P and PSNH entered into certain contracts for the purchase of energy that qualify as leases. These contracts do not have minimum lease payments and therefore are not recognized as a lease liability on the balance sheet and are not reflected in the future minimum lease payments table below. Expense related to these contracts are included as variable lease cost in the table below. The expense and long-term obligation for these contracts are included in the annually reported contractual obligations table in Note 12B, "Commitments and Contingencies - Long-Term Contractual Arrangements," of the Eversource 2018 Form 10-K. The components of lease cost, prior to amounts capitalized, are as follows: For the Three Months Ended September 30, 2019 For the Nine Months Ended September 30, 2019 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Financing Lease Cost: Amortization of Right-of-use-Assets $ 0.4 $ 0.2 $ 0.1 $ — $ 1.1 $ 0.6 $ 0.1 $ 0.1 Interest on Lease Liabilities 0.3 0.1 0.1 — 1.0 0.4 0.4 — Total Finance Lease Cost 0.7 0.3 0.2 — 2.1 1.0 0.5 0.1 Operating Lease Cost 2.9 0.1 0.5 — 8.9 0.3 1.3 0.1 Variable Lease Cost 15.3 3.6 — 11.7 46.4 10.1 — 36.3 Total Lease Cost $ 18.9 $ 4.0 $ 0.7 $ 11.7 $ 57.4 $ 11.4 $ 1.8 $ 36.5 Operating lease cost, less the capitalized portion, is included in Operations and Maintenance (or Purchased Power, Fuel and Transmission expense for transmission segment leases) on the statements of income. Amortization of finance lease assets is included in Depreciation on the statements of income. Interest expense on finance leases is included in Interest Expense, Net on the statements of income. Supplemental balance sheet information related to leases is as follows: As of September 30, 2019 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Operating Leases: Operating Lease Right-of-use-Assets, Net Other Long-Term Assets $ 52.3 $ 0.9 $ 24.2 $ 0.4 Operating Lease Liabilities Operating Lease Liabilities - Current Portion Other Current Liabilities $ 8.9 $ 0.5 $ 0.6 $ — Operating Lease Liabilities - Long-Term Other Long-Term Liabilities 43.4 0.4 23.6 0.4 Total Operating Lease Liabilities $ 52.3 $ 0.9 $ 24.2 $ 0.4 Finance Leases: Finance Lease Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 8.8 $ 2.2 $ 3.4 $ 0.9 Finance Lease Liabilities Finance Lease Liabilities - Current Portion Other Current Liabilities $ 2.3 $ 1.6 $ — $ 0.1 Finance Lease Liabilities - Long-Term Other Long-Term Liabilities 8.7 1.8 4.4 0.8 Total Finance Lease Liabilities $ 11.0 $ 3.4 $ 4.4 $ 0.9 The finance lease payments that NSTAR Electric will make over the next twelve months are entirely interest-related, due to escalating payments. As such, none of the finance lease payments over the next twelve months will reduce the finance lease liability. Other information related to leases is as follows (in millions of dollars, unless otherwise noted): Eversource CL&P NSTAR Electric PSNH As of September 30, 2019 Weighted-Average Remaining Lease Term (Years): Operating Leases 12 2 20 9 Financing Leases 11 2 22 9 Weighted-Average Discount Rate (Percentage): Operating Leases 3.9 % 2.5 % 4.1 % 3.7 % Financing Leases 4.2 % 10.5 % 2.9 % 3.5 % For the Three Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 2.9 $ 0.1 $ 0.5 $ — Operating Cash Flows from Finance Leases 0.3 0.1 0.1 — Financing Cash Flows from Finance Leases 0.5 0.4 — — Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.9 0.8 — — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities — — — — For the Nine Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 8.7 $ 0.3 $ 1.2 $ 0.1 Operating Cash Flows from Finance Leases 1.0 0.4 0.4 — Financing Cash Flows from Finance Leases 1.5 1.0 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.6 1.0 — 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 1.3 — — — Future minimum lease payments, excluding variable costs, under long-term leases, as of September 30, 2019 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH October 1, 2019 through December 31, 2019 $ 2.6 $ 0.1 $ 0.3 $ — $ 0.9 $ 0.5 $ 0.1 $ — Year Ending December 31, 2020 10.1 0.5 1.6 0.1 3.4 2.0 0.5 0.1 2021 8.9 0.2 1.6 0.1 2.9 1.5 0.5 0.1 2022 7.4 — 1.6 0.1 1.5 — 0.6 0.1 2023 4.9 — 1.6 — 0.7 — 0.6 0.1 2024 2.8 — 1.6 — 0.7 — 0.6 0.1 Thereafter 28.9 0.1 28.7 0.2 13.3 — 12.8 0.5 Future lease payments 65.6 0.9 37.0 0.5 23.4 4.0 15.7 1.0 Less amount representing interest 13.3 — 12.8 0.1 12.4 0.6 11.3 0.1 Present value of future minimum lease payments $ 52.3 $ 0.9 $ 24.2 $ 0.4 $ 11.0 $ 3.4 $ 4.4 $ 0.9 At December 31, 2018, future minimum rental payments, excluding executory costs, such as property taxes, state use taxes, insurance, and maintenance were as follows: Operating Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 11.5 $ 1.5 $ 7.2 $ 0.5 2020 9.8 1.4 6.0 0.4 2021 8.7 1.2 5.3 0.4 2022 7.2 1.1 4.4 0.4 2023 4.7 0.5 3.1 0.2 Thereafter 32.7 0.2 29.5 0.3 Future minimum lease payments $ 74.6 $ 5.9 $ 55.5 $ 2.2 Capital Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 3.4 $ 2.0 $ 0.5 $ 0.1 2020 3.4 2.0 0.5 0.1 2021 2.9 1.5 0.5 0.1 2022 1.5 — 0.6 0.1 2023 0.7 — 0.6 0.1 Thereafter 13.9 — 13.4 0.5 Future minimum lease payments 25.8 5.5 16.1 1.0 Less amount representing interest 13.8 1.0 12.4 0.1 Present value of future minimum lease payments $ 12.0 $ 4.5 $ 3.7 $ 0.9

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS The following methods and assumptions were used to estimate the fair value of each of the following financial instruments: Preferred Stock, Long-Term Debt and Rate Reduction Bonds: The fair value of CL&P's and NSTAR Electric's preferred stock is based upon pricing models that incorporate interest rates and other market factors, valuations or trades of similar securities and cash flow projections. The fair value of long-term debt and RRB debt securities is based upon pricing models that incorporate quoted market prices for those issues or similar issues adjusted for market conditions, credit ratings of the respective companies and treasury benchmark yields. The fair values provided in the table below are classified as Level 2 within the fair value hierarchy. Carrying amounts and estimated fair values are as follows: Eversource CL&P NSTAR Electric PSNH (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value As of September 30, 2019: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 160.3 $ 116.2 $ 116.6 $ 43.0 $ 43.7 $ — $ — Long-Term Debt 14,293.2 15,479.2 3,518.5 4,104.4 3,341.6 3,695.3 1,101.5 1,165.7 Rate Reduction Bonds 583.3 634.1 — — — — 583.3 634.1 As of December 31, 2018: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 156.8 $ 116.2 $ 113.8 $ 43.0 $ 43.0 $ — $ — Long-Term Debt 13,086.1 13,154.9 3,254.0 3,429.2 2,944.8 3,024.1 805.2 819.5 Rate Reduction Bonds 635.7 645.8 — — — — 635.7 645.8 Derivative Instruments and Marketable Securities: Derivative instruments and investments in marketable securities are carried at fair value. For further information, see Note 4, "Derivative Instruments," and Note 5, "Marketable Securities," to the financial statements. See Note 1E, "Summary of Significant Accounting Policies - Fair Value Measurements," for the fair value measurement policy and the fair value hierarchy.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS)	ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) The changes in accumulated other comprehensive income/(loss) by component, net of tax, are as follows: For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Qualified Cash Flow Hedging Instruments Unrealized Gains/(Losses) on Marketable Securities Defined Benefit Plans Total Qualified Cash Flow Hedging Instruments Unrealized Losses on Marketable Securities Defined Benefit Plans Total Balance as of January 1st $ (4.4 ) $ (0.5 ) $ (55.1 ) $ (60.0 ) $ (6.2 ) $ — $ (60.2 ) $ (66.4 ) OCI Before Reclassifications — 1.3 2.6 3.9 — (0.7 ) 2.6 1.9 Amounts Reclassified from AOCI 0.9 — 3.2 4.1 1.6 — 3.3 4.9 Net OCI 0.9 1.3 5.8 8.0 1.6 (0.7 ) 5.9 6.8 Balance as of September 30th $ (3.5 ) $ 0.8 $ (49.3 ) $ (52.0 ) $ (4.6 ) $ (0.7 ) $ (54.3 ) $ (59.6 ) Eversource's qualified cash flow hedging instruments represent interest rate swap agreements on debt issuances that were settled in prior years. The settlement amount was recorded in AOCI and is being amortized into Net Income over the term of the underlying debt instrument. CL&P, NSTAR Electric and PSNH continue to amortize interest rate swaps settled in prior years from AOCI into Interest Expense over the remaining life of the associated long-term debt. Such interest rate swaps are not material to their respective financial statements. Defined benefit plan OCI amounts before reclassifications relate to actuarial gains and losses that arose during the year and were recognized in AOCI. The unamortized actuarial gains and losses and prior service costs on the defined benefit plans are amortized from AOCI into Other Income, Net over the average future employee service period, and are reflected in amounts reclassified from AOCI. Eversource did not elect to reclassify the income tax effects of the Tax Cuts and Jobs Act from AOCI to Retained Earnings as permitted by ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220) .

COMMON SHARES

COMMON SHARES	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
COMMON SHARES	COMMON SHARES The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric and PSNH that were authorized and issued, as well as the respective per share par values: Shares Authorized as of September 30, 2019 and December 31, 2018 Issued as of Par Value September 30, 2019 December 31, 2018 Eversource $ 5 380,000,000 339,858,402 333,878,402 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 200 200 PSNH $ 1 100,000,000 301 301 Common Share Issuance and Forward Sale Agreement: On June 4, 2019, Eversource completed an equity offering of 17,940,000 common shares, consisting of 5,980,000 common shares issued directly by the Company and 11,960,000 common shares issuable pursuant to a forward sale agreement with an investment bank. The issuance of 5,980,000 common shares resulted in proceeds of $426.9 million , net of issuance costs, and was reflected in shareholders’ equity and as a financing activity on the statement of cash flows. Under the forward sale agreement, a total of 11,960,000 common shares were borrowed from third parties and sold by the underwriters. The forward sale agreement allows Eversource, at its election and prior to May 29, 2020, to physically settle the forward sale agreement by issuing common shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreement (initially, $71.48 per share) or, alternatively, to settle the forward sale agreement in whole or in part through the delivery or receipt of shares or cash. The forward sale price is subject to adjustment daily based on a floating interest rate factor and will decrease in respect of certain fixed amounts specified in the agreement, such as dividends. Eversource’s intent is to physically settle the forward sale agreement by issuing common shares. As of September 30, 2019 , if Eversource had elected to net settle the forward sale agreement, Eversource would have been required to pay $169.7 million under a cash settlement or would have been required to deliver 1,985,105 common shares under a net share settlement. Issuances of shares under the forward sale agreement are classified as equity transactions. Accordingly, no amounts relating to the forward sale agreement have or will be recorded in the financial statements until settlements take place. Prior to any settlements, the only impact to the financial statements is the inclusion of incremental shares within the calculation of diluted EPS using the treasury stock method. See Note 15, "Earnings Per Share," for information on the forward sale agreement’s impact on the calculation of diluted EPS. Treasury Shares: As of September 30, 2019 and December 31, 2018 , there were 16,124,979 and 16,992,594 Eversource common shares held as treasury shares, respectively. As of September 30, 2019 and December 31, 2018 , Eversource common shares outstanding were 323,733,423 and 316,885,808 , respectively. Beginning in 2019, Eversource began issuing treasury shares to satisfy awards under the Company's incentive plans, shares issued under the dividend reinvestment and share purchase plan, and matching contributions under the Eversource 401k Plan. Dividends on the preferred stock of CL&P and NSTAR Electric totaled $1.9 million for each of the three months ended September 30, 2019 and 2018 and $5.6 million for each of the nine months ended September 30, 2019 and 2018 . These dividends were presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. Noncontrolling Interest – Preferred Stock of Subsidiaries on the Eversource balance sheets totaled $155.6 million as of September 30, 2019 and December 31, 2018 . On the Eversource balance sheets, Common Shareholders' Equity was fully attributable to Eversource parent and Noncontrolling Interest – Preferred Stock of Subsidiaries was fully attributable to the noncontrolling interest.

COMMON SHAREHOLDERS' EQUITY AND

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	COMMON SHARES The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric and PSNH that were authorized and issued, as well as the respective per share par values: Shares Authorized as of September 30, 2019 and December 31, 2018 Issued as of Par Value September 30, 2019 December 31, 2018 Eversource $ 5 380,000,000 339,858,402 333,878,402 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 200 200 PSNH $ 1 100,000,000 301 301 Common Share Issuance and Forward Sale Agreement: On June 4, 2019, Eversource completed an equity offering of 17,940,000 common shares, consisting of 5,980,000 common shares issued directly by the Company and 11,960,000 common shares issuable pursuant to a forward sale agreement with an investment bank. The issuance of 5,980,000 common shares resulted in proceeds of $426.9 million , net of issuance costs, and was reflected in shareholders’ equity and as a financing activity on the statement of cash flows. Under the forward sale agreement, a total of 11,960,000 common shares were borrowed from third parties and sold by the underwriters. The forward sale agreement allows Eversource, at its election and prior to May 29, 2020, to physically settle the forward sale agreement by issuing common shares in exchange for net proceeds at the then-applicable forward sale price specified by the agreement (initially, $71.48 per share) or, alternatively, to settle the forward sale agreement in whole or in part through the delivery or receipt of shares or cash. The forward sale price is subject to adjustment daily based on a floating interest rate factor and will decrease in respect of certain fixed amounts specified in the agreement, such as dividends. Eversource’s intent is to physically settle the forward sale agreement by issuing common shares. As of September 30, 2019 , if Eversource had elected to net settle the forward sale agreement, Eversource would have been required to pay $169.7 million under a cash settlement or would have been required to deliver 1,985,105 common shares under a net share settlement. Issuances of shares under the forward sale agreement are classified as equity transactions. Accordingly, no amounts relating to the forward sale agreement have or will be recorded in the financial statements until settlements take place. Prior to any settlements, the only impact to the financial statements is the inclusion of incremental shares within the calculation of diluted EPS using the treasury stock method. See Note 15, "Earnings Per Share," for information on the forward sale agreement’s impact on the calculation of diluted EPS. Treasury Shares: As of September 30, 2019 and December 31, 2018 , there were 16,124,979 and 16,992,594 Eversource common shares held as treasury shares, respectively. As of September 30, 2019 and December 31, 2018 , Eversource common shares outstanding were 323,733,423 and 316,885,808 , respectively. Beginning in 2019, Eversource began issuing treasury shares to satisfy awards under the Company's incentive plans, shares issued under the dividend reinvestment and share purchase plan, and matching contributions under the Eversource 401k Plan. Dividends on the preferred stock of CL&P and NSTAR Electric totaled $1.9 million for each of the three months ended September 30, 2019 and 2018 and $5.6 million for each of the nine months ended September 30, 2019 and 2018 . These dividends were presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. Noncontrolling Interest – Preferred Stock of Subsidiaries on the Eversource balance sheets totaled $155.6 million as of September 30, 2019 and December 31, 2018 . On the Eversource balance sheets, Common Shareholders' Equity was fully attributable to Eversource parent and Noncontrolling Interest – Preferred Stock of Subsidiaries was fully attributable to the noncontrolling interest.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic EPS is computed based upon the weighted average number of common shares outstanding during each period. Diluted EPS is computed on the basis of the weighted average number of common shares outstanding plus the potential dilutive effect of certain share-based compensation awards and the equity forward sale agreement, as if they were converted into outstanding common shares. The dilutive effect of unvested RSU and performance share awards, as well as the equity forward sale agreement, is calculated using the treasury stock method. RSU and performance share awards are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. As described in Note 13, "Common Shares," earnings per share dilution, if any, related to the forward sale agreement will be determined under the treasury stock method until settlement of the forward sale agreement. Under this method, the number of Eversource common shares used in calculating diluted EPS is deemed to be increased by the excess, if any, of the number of shares that would be issued upon physical settlement of the forward sale agreement less the number of shares that would be purchased by Eversource in the market (based on the average market pri ce during the same reporting period) using the proceeds receivable upon settlement (based on the adjusted forward sale price at the end of that reporting period). Share dilution occurs when the average market price of Eversource's common shares is higher than the adjusted forward sale price. The following table sets forth the components of basic and diluted EPS: Eversource (Millions of Dollars, except share information) For the Three Months Ended For the Nine Months Ended September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Net Income Attributable to Common Shareholders $ 318.9 $ 289.4 $ 659.0 $ 801.7 Weighted Average Common Shares Outstanding: Basic 324,037,169 317,360,110 320,442,253 317,367,252 Dilutive Effect of: Share-Based Compensation Awards and Other 737,972 607,201 691,636 581,246 Equity Forward Sale Agreement 1,233,201 — 437,037 — Total Dilutive Effect 1,971,173 607,201 1,128,673 581,246 Diluted 326,008,342 317,967,311 321,570,926 317,948,498 Basic EPS $ 0.98 $ 0.91 $ 2.06 $ 2.53 Diluted EPS $ 0.98 $ 0.91 $ 2.05 $ 2.52

REVENUES

REVENUES	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
REVENUES	REVENUES The following tables present operating revenues disaggregated by revenue source: For the Three Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,041.4 $ 43.0 $ — $ 40.0 $ — $ — $ 1,124.4 Commercial 736.6 41.6 — 17.8 — (1.4 ) 794.6 Industrial 90.6 18.1 — 1.3 — (3.2 ) 106.8 Total Retail Tariff Sales Revenues 1,868.6 102.7 — 59.1 — (4.6 ) 2,025.8 Wholesale Transmission Revenues — — 365.5 — 15.4 (300.7 ) 80.2 Wholesale Market Sales Revenues 33.1 5.5 — 1.3 — — 39.9 Other Revenues from Contracts with Customers 12.3 0.5 3.1 1.7 242.7 (243.0 ) 17.3 Reserve for Revenues Subject to Refund 4.5 1.5 — (0.8 ) — — 5.2 Total Revenues from Contracts with Customers 1,918.5 110.2 368.6 61.3 258.1 (548.3 ) 2,168.4 Alternative Revenue Programs 6.7 (7.6 ) (20.9 ) 2.6 — 19.0 (0.2 ) Other Revenues (1) 6.4 0.8 0.1 0.3 — — 7.6 Total Operating Revenues $ 1,931.6 $ 103.4 $ 347.8 $ 64.2 $ 258.1 $ (529.3 ) $ 2,175.8 For the Nine Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 2,879.8 $ 402.0 $ — $ 100.5 $ — $ — $ 3,382.3 Commercial 2,002.0 254.9 — 48.1 — (3.4 ) 2,301.6 Industrial 254.0 72.5 — 3.5 — (8.7 ) 321.3 Total Retail Tariff Sales Revenues 5,135.8 729.4 — 152.1 — (12.1 ) 6,005.2 Wholesale Transmission Revenues — — 971.6 — 43.7 (811.4 ) 203.9 Wholesale Market Sales Revenues 123.9 41.6 — 3.2 — — 168.7 Other Revenues from Contracts with Customers 40.0 1.9 9.9 5.2 723.4 (725.2 ) 55.2 Reserve for Revenues Subject to Refund (1.7 ) 4.7 — (1.9 ) — — 1.1 Total Revenues from Contracts with Customers 5,298.0 777.6 981.5 158.6 767.1 (1,548.7 ) 6,434.1 Alternative Revenue Programs 15.0 — 56.1 4.2 — (50.8 ) 24.5 Other Revenues (1) 14.2 2.3 0.3 0.7 — — 17.5 Total Operating Revenues $ 5,327.2 $ 779.9 $ 1,037.9 $ 163.5 $ 767.1 $ (1,599.5 ) $ 6,476.1 For the Three Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,111.7 $ 42.8 $ — $ 41.2 $ — $ — $ 1,195.7 Commercial 789.6 40.8 — 17.9 — (1.2 ) 847.1 Industrial 98.7 18.9 — 1.3 — (2.6 ) 116.3 Total Retail Tariff Sales Revenues 2,000.0 102.5 — 60.4 — (3.8 ) 2,159.1 Wholesale Transmission Revenues — — 364.5 — 11.7 (300.2 ) 76.0 Wholesale Market Sales Revenues 48.8 11.4 — 1.3 — — 61.5 Other Revenues from Contracts with Customers 20.2 (0.5 ) 3.1 1.9 212.9 (213.5 ) 24.1 Reserve for Revenues Subject to Refund 5.2 (3.5 ) — (1.3 ) — — 0.4 Total Revenues from Contracts with Customers 2,074.2 109.9 367.6 62.3 224.6 (517.5 ) 2,321.1 Alternative Revenue Programs (51.6 ) (1.5 ) (37.0 ) 1.1 — 33.8 (55.2 ) Other Revenues 4.8 0.6 — 0.1 — — 5.5 Total Operating Revenues $ 2,027.4 $ 109.0 $ 330.6 $ 63.5 $ 224.6 $ (483.7 ) $ 2,271.4 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 2,900.4 $ 395.9 $ — $ 100.9 $ — $ — $ 3,397.2 Commercial 2,023.0 245.4 — 47.9 — (3.4 ) 2,312.9 Industrial 268.6 71.9 — 3.4 — (7.5 ) 336.4 Total Retail Tariff Sales Revenues 5,192.0 713.2 — 152.2 — (10.9 ) 6,046.5 Wholesale Transmission Revenues — — 988.9 — 34.4 (826.9 ) 196.4 Wholesale Market Sales Revenues 141.4 41.4 — 3.1 — — 185.9 Other Revenues from Contracts with Customers 54.4 (1.4 ) 9.4 5.4 658.1 (659.8 ) 66.1 Reserve for Revenues Subject to Refund (21.2 ) (11.5 ) — (3.3 ) — — (36.0 ) Total Revenues from Contracts with Customers 5,366.6 741.7 998.3 157.4 692.5 (1,497.6 ) 6,458.9 Alternative Revenue Programs (57.2 ) (3.2 ) (45.3 ) 3.7 — 41.5 (60.5 ) Other Revenues 12.4 2.0 — 0.4 — — 14.8 Total Operating Revenues $ 5,321.8 $ 740.5 $ 953.0 $ 161.5 $ 692.5 $ (1,456.1 ) $ 6,413.2 For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 513.6 $ 374.4 $ 153.4 $ 539.6 $ 414.8 $ 157.3 Commercial 247.0 406.1 84.1 259.0 443.8 87.3 Industrial 37.4 32.4 20.8 39.4 38.0 21.3 Total Retail Tariff Sales Revenues 798.0 812.9 258.3 838.0 896.6 265.9 Wholesale Transmission Revenues 175.2 132.9 57.4 179.1 128.3 57.1 Wholesale Market Sales Revenues 13.8 14.4 4.9 13.3 18.1 17.4 Other Revenues from Contracts with Customers 9.0 3.1 4.0 9.3 10.3 4.0 Reserve for Revenues Subject to Refund — — 4.5 8.3 — (3.1 ) Total Revenues from Contracts with Customers 996.0 963.3 329.1 1,048.0 1,053.3 341.3 Alternative Revenue Programs (15.2 ) 9.8 (8.8 ) (64.3 ) (15.4 ) (8.9 ) Other Revenues (1) 4.1 1.8 0.6 2.8 1.8 0.2 Eliminations (131.0 ) (96.2 ) (40.5 ) (121.5 ) (100.2 ) (42.4 ) Total Operating Revenues $ 853.9 $ 878.7 $ 280.4 $ 865.0 $ 939.5 $ 290.2 For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,426.9 $ 1,027.8 $ 425.1 $ 1,410.0 $ 1,071.6 $ 418.8 Commercial 708.4 1,058.3 236.8 702.2 1,083.8 238.4 Industrial 105.8 90.1 58.1 111.8 96.9 59.9 Total Retail Tariff Sales Revenues 2,241.1 2,176.2 720.0 2,224.0 2,252.3 717.1 Wholesale Transmission Revenues 445.9 383.1 142.6 469.8 367.7 151.4 Wholesale Market Sales Revenues 39.6 55.9 28.4 34.3 56.4 52.3 Other Revenues from Contracts with Customers 27.0 13.2 11.8 25.0 27.9 11.4 Reserve for Revenues Subject to Refund — — (1.7 ) (8.3 ) (3.7 ) (9.2 ) Total Revenues from Contracts with Customers 2,753.6 2,628.4 901.1 2,744.8 2,700.6 923.0 Alternative Revenue Programs 45.6 19.1 6.4 (68.4 ) (15.6 ) (18.5 ) Other Revenues (1) 7.9 5.2 1.4 6.5 5.1 0.8 Eliminations (363.1 ) (294.5 ) (111.1 ) (338.0 ) (289.8 ) (112.6 ) Total Operating Revenues $ 2,444.0 $ 2,358.2 $ 797.8 $ 2,344.9 $ 2,400.3 $ 792.7 (1) Other Revenues include certain fees charged to customers, which are not considered revenue from contracts with customers. Other revenues also includes lease revenues under lessor accounting guidance of $1.2 million at Eversource, $0.3 million at CL&P, and $0.7 million at NSTAR Electric for the three months ended September 30, 2019 , and $3.4 million at Eversource, $0.7 million at CL&P, and $2.0 million at NSTAR Electric for the nine months ended September 30, 2019 , respectively.

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION Eversource is organized into the Electric Distribution, Electric Transmission, Natural Gas Distribution and Water Distribution reportable segments and Other based on a combination of factors, including the characteristics of each segments' services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates. These reportable segments represent substantially all of Eversource's total consolidated revenues. Revenues from the sale of electricity, natural gas and water primarily are derived from residential, commercial and industrial customers and are not dependent on any single customer. The Electric Distribution reportable segment includes the results of PSNH's generation facilities prior to sales in January and August 2018, and NSTAR Electric's solar power facilities. Eversource's reportable segments are determined based upon the level at which Eversource's chief operating decision maker assesses performance and makes decisions about the allocation of company resources. The remainder of Eversource's operations is presented as Other in the tables below and primarily consists of 1) the equity in earnings of Eversource parent from its subsidiaries and intercompany interest income, both of which are eliminated in consolidation, and interest expense related to the debt of Eversource parent, 2) the revenues and expenses of Eversource Service, most of which are eliminated in consolidation, 3) the operations of CYAPC and YAEC, 4) Eversource Water Ventures, Inc., parent company of Aquarion, and 5) the results of other unregulated subsidiaries, which are not part of its core business. In addition, Other in the tables below includes Eversource parent's equity ownership interests that are not consolidated, which include a natural gas pipeline owned by Enbridge, Inc., the offshore wind business, a renewable energy investment fund, and two companies that transmit hydroelectricity imported from the Hydro-Quebec system in Canada. In the ordinary course of business, Yankee Gas and NSTAR Gas purchase natural gas transmission services from the Enbridge, Inc. natural gas pipeline project described above. These affiliate transaction costs total approximately $62.5 million annually and are classified as Purchased Power, Fuel and Transmission on the Eversource statements of income. Each of Eversource's subsidiaries, including CL&P, NSTAR Electric and PSNH, has one reportable segment. Cash flows used for investments in plant included in the segment information below are cash capital expenditures that do not include amounts incurred but not paid, cost of removal, AFUDC related to equity funds, and the capitalized portions of pension and PBOP expense. Eversource's segment information is as follows: For the Three Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 1,931.6 $ 103.4 $ 347.8 $ 64.2 $ 258.1 $ (529.3 ) $ 2,175.8 Depreciation and Amortization (188.4 ) (16.1 ) (64.3 ) (11.1 ) (17.2 ) 0.6 (296.5 ) Other Operating Expenses (1,448.2 ) (99.3 ) (159.6 ) (25.5 ) (275.9 ) 638.4 (1,370.1 ) Operating Income/(Loss) $ 295.0 $ (12.0 ) $ 123.9 $ 27.6 $ (35.0 ) $ 109.7 $ 509.2 Interest Expense $ (53.2 ) $ (11.7 ) $ (33.6 ) $ (8.9 ) $ (41.7 ) $ 13.9 $ (135.2 ) Other Income/(Loss), Net 13.9 — 61.4 (0.2 ) 497.0 (545.1 ) 27.0 Net Income/(Loss) Attributable to Common Shareholders 197.3 (17.1 ) 107.5 17.5 435.2 (421.5 ) 318.9 For the Nine Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 5,327.2 $ 779.9 $ 1,037.9 $ 163.5 $ 767.1 $ (1,599.5 ) $ 6,476.1 Depreciation and Amortization (517.6 ) (56.0 ) (188.0 ) (35.0 ) (45.6 ) 1.7 (840.5 ) Impairment of Northern Pass Transmission — — (239.6 ) — — — (239.6 ) Other Operating Expenses (4,166.8 ) (620.4 ) (366.9 ) (75.4 ) (719.8 ) 1,708.2 (4,241.1 ) Operating Income $ 642.8 $ 103.5 $ 243.4 $ 53.1 $ 1.7 $ 110.4 $ 1,154.9 Interest Expense $ (153.3 ) $ (35.4 ) $ (94.5 ) $ (26.2 ) $ (130.3 ) $ 40.0 $ (399.7 ) Other Income, Net 44.2 1.1 78.2 0.2 813.7 (833.6 ) 103.8 Net Income Attributable to Common Shareholders 422.7 57.6 138.4 26.3 697.2 (683.2 ) 659.0 Cash Flows Used for Investments in Plant 861.0 327.8 686.7 79.9 173.6 — 2,129.0 For the Three Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 2,027.4 $ 109.0 $ 330.6 $ 63.5 $ 224.6 $ (483.7 ) $ 2,271.4 Depreciation and Amortization (206.1 ) (13.9 ) (58.3 ) (11.7 ) (12.0 ) 0.6 (301.4 ) Other Operating Expenses (1,562.2 ) (102.4 ) (96.7 ) (25.5 ) (200.9 ) 483.7 (1,504.0 ) Operating Income/(Loss) $ 259.1 $ (7.3 ) $ 175.6 $ 26.3 $ 11.7 $ 0.6 $ 466.0 Interest Expense $ (52.4 ) $ (11.3 ) $ (30.3 ) $ (8.5 ) $ (30.5 ) $ 7.8 $ (125.2 ) Other Income, Net 32.2 1.5 9.0 0.7 251.7 (278.4 ) 16.7 Net Income/(Loss) Attributable to Common Shareholders 173.8 (12.6 ) 109.5 17.6 271.1 (270.0 ) 289.4 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 5,321.8 $ 740.5 $ 953.0 $ 161.5 $ 692.5 $ (1,456.1 ) $ 6,413.2 Depreciation and Amortization (486.0 ) (59.6 ) (171.8 ) (34.6 ) (35.9 ) 1.7 (786.2 ) Other Operating Expenses (4,238.6 ) (585.7 ) (268.7 ) (73.9 ) (617.2 ) 1,457.0 (4,327.1 ) Operating Income $ 597.2 $ 95.2 $ 512.5 $ 53.0 $ 39.4 $ 2.6 $ 1,299.9 Interest Expense $ (152.0 ) $ (33.7 ) $ (89.9 ) $ (25.5 ) $ (94.8 ) $ 23.2 $ (372.7 ) Other Income/(Loss), Net 70.9 5.1 26.7 (0.4 ) 913.8 (915.4 ) 100.7 Net Income Attributable to Common Shareholders 379.3 50.2 329.6 26.3 905.9 (889.6 ) 801.7 Cash Flows Used for Investments in Plant 717.4 245.5 735.8 68.1 118.3 — 1,885.1 The following table summarizes Eversource's segmented total assets: Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Water Distribution Other Eliminations Total As of September 30, 2019 $ 21,999.4 $ 4,103.5 $ 10,666.9 $ 2,311.9 $ 19,137.8 $ (18,494.1 ) $ 39,725.4 As of December 31, 2018 21,389.1 3,904.9 10,285.0 2,253.0 17,874.2 (17,464.9 ) 38,241.3 For further information regarding the 2019 impairment of NPT, see Note 1C, "Summary of Significant Accounting Policies - Impairment of Northern Pass Transmission," to the financial statements.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Eversource Energy is a public utility holding company primarily engaged, through its wholly-owned regulated utility subsidiaries, in the energy delivery business. Eversource Energy's wholly-owned regulated utility subsidiaries consist of CL&P, NSTAR Electric and PSNH (electric utilities), Yankee Gas and NSTAR Gas (natural gas utilities) and Aquarion (water utilities). Eversource provides energy delivery and/or water service to approximately four million electric, natural gas and water customers through eight regulated utilities in Connecticut, Massachusetts and New Hampshire. The unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH include the accounts of each of their respective subsidiaries. Intercompany transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH and the unaudited condensed financial statements of CL&P are herein collectively referred to as the "financial statements." The combined notes to the financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures included in annual financial statements prepared in accordance with GAAP have been omitted pursuant to such rules and regulations. The accompanying financial statements should be read in conjunction with the Combined Notes to Financial Statements included in Item 8, "Financial Statements and Supplementary Data," of the Eversource 2018 Form 10-K, which was filed with the SEC on February 26, 2019. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource's, CL&P's, NSTAR Electric's and PSNH's financial position as of September 30, 2019 and December 31, 2018 , and the results of operations, comprehensive income and common shareholders' equity for the three and nine months ended September 30, 2019 and 2018 , and the cash flows for the nine months ended September 30, 2019 and 2018 . The results of operations and comprehensive income for the three and nine months ended September 30, 2019 and 2018 and the cash flows for the nine months ended September 30, 2019 and 2018 are not necessarily indicative of the results expected for a full year. Eversource consolidates CYAPC and YAEC because CL&P's, NSTAR Electric's and PSNH's combined ownership and voting interests in each of these entities is greater than 50 percent. Intercompany transactions between CL&P, NSTAR Electric, PSNH and the CYAPC and YAEC companies have been eliminated in consolidation of the Eversource financial statements. Eversource's utility subsidiaries' electric, natural gas and water distribution and transmission businesses are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for entities with rate-regulated operations, which considers the effect of regulation on the differences in the timing of the recognition of certain revenues and expenses from those of other businesses and industries. See Note 2, "Regulatory Accounting," for further information. Certain reclassifications of prior period data were made in the accompanying financial statements to conform to the current period presentation.
Accounting Standards	Accounting Standards Accounting Standards Issued but Not Yet Effective: In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326), which provides a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. Under the new guidance, immediate recognition of all credit losses expected over the life of a financial instrument is required. The standard is effective January 1, 2020 a nd requires a modified retrospective method through a cumulative effect adjustment to retained earnings. The Company is assessing the impacts of this standard on the accounting for credit losses on its financial instruments, including accounts receivable, and does not expect it to have a material impact on the financial statements. Accounting Standards Recently Adopted: On January 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842), which amended existing lease accounting guidance. The Company applied the Topic 842 lease criteria to new leases and lease renewals entered into effective on or after January 1, 2019. The ASU required balance sheet recognition of leases deemed to be operating leases as well as additional disclosure requirements. The recognition, measurement and presentation of expenses and cash flows were not significantly changed. The Company also adopted the modified retrospective transition method allowed in ASU 2018-11, Leases (Topic 842) - Targeted Improvements , which allowed the Company to adopt the new leases standard as of January 1, 2019, with prior periods presented in the financial statements continuing to follow existing lease accounting guidance under Topic 840 (Leases) in the accounting literature. Implementation of ASU 2018-11 had no effect on retained earnings, and the requirements of the new lease standard (Topic 842) are reflected in the 2019 financial statements and footnotes. The Company elected the practical expedient package whereby it did not need to reassess whether or not an existing contract is or contains a lease or whether a lease is an operating or capital lease, and it did not need to reassess initial direct costs for leases. Election of this practical expedient allowed us to carry forward our historical lease classifications. The Company elected the practical expedient to not reevaluate land easements existing at adoption if they were not previously accounted for as leases. The Company also elected to use the discount rate as of the January 1, 2019 implementation date to discount its operating lease liabilities. The Company did not elect the hindsight practical expedient to determine the lease term for existing leases. The Company determined the impact the ASUs had on its financial statements by reviewing its lease population and identifying lease data needed for the disclosure requirements. The Company implemented a new lease accounting system in 2019 to ensure ongoing compliance with the ASU’s requirements. Adoption of the new standard resulted in the recording of operating lease liabilities and right-of-use assets on the balance sheet upon transition at January 1, 2019 of $58.0 million at Eversource, $25.3 million at NSTAR Electric, $0.6 million at CL&P, and $0.6 million
Provision for Uncollectible Accounts	Provision for Uncollectible Accounts Eversource, including CL&P, NSTAR Electric and PSNH, presents its receivables at estimated net realizable value by maintaining a provision for uncollectible accounts. This provision is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. The estimate is based upon historical collection and write-off experience and management's assessment of collectability from customers. Management continuously assesses the collectability of receivables and adjusts collectability estimates based on actual experience. Receivable balances are written off against the provision for uncollectible accounts when the customer accounts are terminated and these balances are deemed to be uncollectible. The PURA allows CL&P and Yankee Gas to accelerate the recovery of accounts receivable balances attributable to qualified customers under financial or medical duress (uncollectible hardship accounts receivable) outstanding for greater than 180 days and 90 days , respectively. The DPU allows NSTAR Electric and NSTAR Gas to recover in rates amounts associated with certain uncollectible hardship accounts receivable. These uncollectible hardship customer account balances are included in Regulatory Assets or Other Long-Term Assets on the balance sheets.
Fair Value Measurements	Fair Value Measurements Fair value measurement guidance is applied to derivative contracts that are not elected or designated as "normal purchases" or "normal sales" ("normal") and to the marketable securities held in trusts. Fair value measurement guidance is also applied to valuations of the investments used to calculate the funded status of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial assets such as goodwill and AROs, and the estimated fair value of preferred stock, long-term debt and RRBs. Fair Value Hierarchy: In measuring fair value, Eversource uses observable market data when available in order to minimize the use of unobservable inputs. Inputs used in fair value measurements are categorized into three fair value hierarchy levels for disclosure purposes. The entire fair value measurement is categorized based on the lowest level of input that is significant to the fair value measurement. Eversource evaluates the classification of assets and liabilities measured at fair value on a quarterly basis, and Eversource's policy is to recognize transfers between levels of the fair value hierarchy as of the end of the reporting period. The three levels of the fair value hierarchy are described below: Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 - Inputs are quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs are observable. Level 3 - Quoted market prices are not available. Fair value is derived from valuation techniques in which one or more significant inputs or assumptions are unobservable. Where possible, valuation techniques incorporate observable market inputs that can be validated to external sources such as industry exchanges, including prices of energy and energy-related products. Uncategorized - Investments that are measured at net asset value are not categorized within the fair value hierarchy.
Other Taxes	Other TaxesEversource's companies that serve customers in Connecticut collect gross receipts taxes levied by the state of Connecticut from their customers. As agents for state and local governments, Eversource's companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income. Separate from above were amounts recorded as Taxes Other Than Income Taxes related to the remittance to the State of Connecticut of energy efficiency funds collected from customers in Operating Revenues. These amounts were $21.4 million for the nine months ended September 30, 2019 , and $10.7 million and $36.1 million for the three and nine months ended September 30, 2018, respectively. Energy efficiency funds collected from customers after July 1, 2019 are no longer subject to remittance to the State of Connecticut. These amounts were recorded separately, with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the Eversource and CL&P statements of income.
Restricted Cash	Restricted cash included in Prepayments and Other Current Assets primarily represents cash collections related to the PSNH RRB customer charges that are held in trust, and required ISO-NE cash deposits. R
Earnings Per Share	Basic EPS is computed based upon the weighted average number of common shares outstanding during each period. Diluted EPS is computed on the basis of the weighted average number of common shares outstanding plus the potential dilutive effect of certain share-based compensation awards and the equity forward sale agreement, as if they were converted into outstanding common shares. The dilutive effect of unvested RSU and performance share awards, as well as the equity forward sale agreement, is calculated using the treasury stock method. RSU and performance share awards are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. As described in Note 13, "Common Shares," earnings per share dilution, if any, related to the forward sale agreement will be determined under the treasury stock method until settlement of the forward sale agreement. Under this method, the number of Eversource common shares used in calculating diluted EPS is deemed to be increased by the excess, if any, of the number of shares that would be issued upon physical settlement of the forward sale agreement less the number of shares that would be purchased by Eversource in the market (based on the average market pri ce during the same reporting period) using the proceeds receivable upon settlement (based on the adjusted forward sale price at the end of that reporting period). Share dilution occurs when the average market price of Eversource's common shares is higher than the adjusted forward sale price.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Provision for Uncollectible Accounts	The provision balances are as follows: Total Provision for Uncollectible Accounts Provision for Uncollectible Hardship Accounts (Millions of Dollars) As of September 30, 2019 As of December 31, 2018 As of September 30, 2019 As of December 31, 2018 Eversource $ 225.5 $ 212.7 $ 146.5 $ 131.5 CL&P 94.1 88.0 77.8 71.9 NSTAR Electric 80.7 74.5 49.4 42.5 PSNH 10.6 11.1 — — Uncollectible expense associated with customers' accounts receivable included in Operations and Maintenance expense on the statements of income is as follows: For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Eversource $ 14.9 $ 21.5 $ 46.4 $ 50.7 CL&P 4.5 4.4 12.1 12.1 NSTAR Electric 7.0 9.1 18.6 20.4 PSNH 1.8 1.6 5.0 4.9
Components of Other Income, Net	The components of Other Income, Net on the statements of income were as follows: For the Three Months Ended September 30, 2019 September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Pension, SERP and PBOP Non-Service Income Components $ 10.1 $ 1.7 $ 5.6 $ 1.4 $ 14.8 $ 2.0 $ 9.0 $ 2.0 AFUDC Equity 10.5 3.6 5.6 1.0 12.0 3.3 4.2 — Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates (1) 6.1 — 0.2 — (27.9 ) — 0.2 — Investment Income/(Loss) (2.8 ) (0.8 ) (0.9 ) (0.3 ) 1.8 0.7 (0.4 ) 0.1 Interest Income (2) 2.9 0.3 0.1 2.5 10.8 0.9 0.2 9.6 Gain on Sale of Property — — — — 5.0 — 0.5 4.4 Other 0.2 — 0.1 — 0.2 0.2 — — Total Other Income, Net $ 27.0 $ 4.8 $ 10.7 $ 4.6 $ 16.7 $ 7.1 $ 13.7 $ 16.1 For the Nine Months Ended September 30, 2019 September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Pension, SERP and PBOP Non-Service Income Components $ 23.2 $ 0.1 $ 18.0 $ 3.5 $ 44.6 $ 7.3 $ 26.8 $ 6.4 AFUDC Equity 34.5 9.4 14.7 2.1 32.6 9.4 11.5 — Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates (1) 37.0 0.2 0.6 — (0.4 ) — 0.6 — Investment Income/(Loss) (2.3 ) 0.9 (1.5 ) — 2.2 0.9 0.6 0.2 Interest Income (2) 10.8 1.1 0.5 9.0 16.2 2.9 0.6 13.3 Gain on Sale of Property 0.2 — — — 5.0 — 0.5 4.4 Other 0.4 (0.1 ) 0.2 — 0.5 0.2 — — Total Other Income, Net $ 103.8 $ 11.6 $ 32.5 $ 14.6 $ 100.7 $ 20.7 $ 40.6 $ 24.3 (1) For the three and nine months ended September 30, 2018, equity in earnings/(loss) and impairment of unconsolidated affiliates includes an other-than-temporary impairment of $32.9 million of the Access Northeast project investment. For the nine months ended September 30, 2019 and 2018, equity in earnings includes $20.4 million and $17.6 million , respectively, of unrealized gains associated with an investment in a renewable energy fund. (2) For the nine months ended September 30, 2019, see Note 2, "Regulatory Accounting," for further information on $5.2 million of interest income recognized in 2019 for the equity return component of carrying charges on storm costs at PSNH. For the three and nine months ended September 30, 2018, PSNH recognized $8.7 million for the equity return component of carrying charges on storm costs incurred from August 2011 through March 2013.
Other Taxes	These gross receipts taxes are recorded separately with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the statements of income as follows: For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Eversource $ 42.6 $ 43.5 $ 124.0 $ 122.5 CL&P 39.8 40.6 107.8 107.7
Non-cash Investing Activities	Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of September 30, 2019 As of September 30, 2018 Eversource $ 317.8 $ 303.7 CL&P 107.6 103.0 NSTAR Electric 79.0 62.5 PSNH 35.8 48.3
Reconciliation of Cash Balances to Cash and Restricted Cash	The following table reconciles cash as reported on the balance sheets to the cash and restricted cash balance as reported on the statements of cash flows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Cash as reported on the Balance Sheets $ 22.7 $ 9.3 $ 0.3 $ 1.6 $ 108.1 $ 87.7 $ 1.6 $ 1.4 Restricted cash included in: Prepayments and Other Current Assets 37.7 4.6 6.1 18.5 72.1 3.5 13.0 47.5 Marketable Securities 19.6 0.4 0.1 0.7 25.9 0.4 0.1 0.6 Other Long-Term Assets 71.9 — — 3.2 3.2 — — 3.2 Cash and Restricted Cash reported on the Statements of Cash Flows $ 151.9 $ 14.3 $ 6.5 $ 24.0 $ 209.3 $ 91.6 $ 14.7 $ 52.7

REGULATORY ACCOUNTING (Tables)

REGULATORY ACCOUNTING (Tables)	9 Months Ended
	Sep. 30, 2019
Regulated Operations [Abstract]
Components of Regulatory Assets	The components of regulatory assets were as follows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Benefit Costs $ 1,835.1 $ 400.5 $ 542.8 $ 148.5 $ 1,914.8 $ 424.7 $ 544.4 $ 169.6 Income Taxes, Net 713.4 460.2 108.6 11.4 728.6 454.4 105.9 8.3 Securitized Stranded Costs 576.1 — — 576.1 608.4 — — 608.4 Storm Restoration Costs, Net 508.9 258.9 190.2 59.8 576.0 302.6 212.9 60.5 Regulatory Tracker Mechanisms 282.7 56.5 121.1 58.1 316.0 33.2 169.1 67.3 Derivative Liabilities 345.8 342.3 — — 356.5 356.5 — — Goodwill-related 335.7 — 288.3 — 348.4 — 299.1 — Asset Retirement Obligations 101.3 33.8 51.7 3.5 89.2 32.3 42.2 3.3 Other Regulatory Assets 131.8 25.6 57.6 13.0 208.0 27.0 64.6 12.1 Total Regulatory Assets 4,830.8 1,577.8 1,360.3 870.4 5,145.9 1,630.7 1,438.2 929.5 Less: Current Portion 538.2 173.3 201.2 78.1 514.8 125.2 241.7 67.2 Total Long-Term Regulatory Assets $ 4,292.6 $ 1,404.5 $ 1,159.1 $ 792.3 $ 4,631.1 $ 1,505.5 $ 1,196.5 $ 862.3
Components of Regulatory Liabilities	The components of regulatory liabilities were as follows: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH EDIT due to Tax Cuts and Jobs Act $ 2,846.9 $ 1,025.7 $ 1,083.2 $ 394.0 $ 2,883.0 $ 1,031.0 $ 1,103.7 $ 396.4 Cost of Removal 552.0 56.3 325.2 20.5 521.0 39.9 307.1 22.1 Benefit Costs 79.7 — 67.4 — 91.2 — 76.9 — Regulatory Tracker Mechanisms 404.3 169.7 167.9 43.3 309.0 89.5 163.7 48.3 AFUDC - Transmission 72.6 46.4 26.2 — 70.7 47.4 23.3 — Revenue Subject to Refund due to Tax Cuts and Jobs Act 18.3 — — 9.0 24.6 — — 12.6 Other Regulatory Liabilities 111.9 29.9 49.1 6.0 80.2 24.0 29.2 4.2 Total Regulatory Liabilities 4,085.7 1,328.0 1,719.0 472.8 3,979.7 1,231.8 1,703.9 483.6 Less: Current Portion 441.2 168.1 199.4 54.7 370.2 109.6 190.6 55.5 Total Long-Term Regulatory Liabilities $ 3,644.5 $ 1,159.9 $ 1,519.6 $ 418.1 $ 3,609.5 $ 1,122.2 $ 1,513.3 $ 428.1

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION (Tables)	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Public Utility Property, Plant, and Equipment	The following tables summarize property, plant and equipment by asset category: Eversource As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Distribution - Electric $ 15,737.6 $ 15,071.1 Distribution - Natural Gas 3,723.7 3,546.2 Transmission - Electric 10,570.6 10,153.9 Distribution - Water 1,686.3 1,639.8 Solar 199.2 164.1 Utility 31,917.4 30,575.1 Other (1) 935.2 778.6 Property, Plant and Equipment, Gross 32,852.6 31,353.7 Less: Accumulated Depreciation Utility (7,417.6 ) (7,126.2 ) Other (375.1 ) (336.7 ) Total Accumulated Depreciation (7,792.7 ) (7,462.9 ) Property, Plant and Equipment, Net 25,059.9 23,890.8 Construction Work in Progress 1,852.0 1,719.6 Total Property, Plant and Equipment, Net $ 26,911.9 $ 25,610.4 As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Distribution - Electric $ 6,417.9 $ 7,102.3 $ 2,257.7 $ 6,176.4 $ 6,756.4 $ 2,178.6 Transmission - Electric 4,938.5 4,186.6 1,440.7 4,700.5 4,065.9 1,338.7 Solar — 199.2 — — 164.1 — Property, Plant and Equipment, Gross 11,356.4 11,488.1 3,698.4 10,876.9 10,986.4 3,517.3 Less: Accumulated Depreciation (2,370.6 ) (2,860.3 ) (803.0 ) (2,302.6 ) (2,702.0 ) (772.9 ) Property, Plant and Equipment, Net 8,985.8 8,627.8 2,895.4 8,574.3 8,284.4 2,744.4 Construction Work in Progress 470.8 636.4 136.6 335.4 510.3 135.7 Total Property, Plant and Equipment, Net $ 9,456.6 $ 9,264.2 $ 3,032.0 $ 8,909.7 $ 8,794.7 $ 2,880.1 (1) These assets are primarily comprised of building improvements, computer software, hardware and equipment at Eversource Service.

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Fair Values and Net Amounts of Contracts	The following table presents the gross fair values of contracts, categorized by risk type, and the net amounts recorded as current or long-term derivative assets or liabilities: As of September 30, 2019 As of December 31, 2018 (Millions of Dollars) Fair Value Hierarchy Commodity Supply and Price Risk Management Netting (1) Net Amount Recorded as a Derivative Commodity Supply and Price Risk Netting (1) Net Amount Recorded as a Derivative Current Derivative Assets: CL&P Level 3 $ 11.6 $ (0.3 ) $ 11.3 $ 9.6 $ (3.4 ) $ 6.2 Other Level 2 — — — 1.5 (0.9 ) 0.6 Long-Term Derivative Assets: CL&P Level 3 70.9 (2.2 ) 68.7 74.2 (2.3 ) 71.9 Current Derivative Liabilities: CL&P Level 3 (64.6 ) — (64.6 ) (55.1 ) — (55.1 ) Other Level 2 (3.5 ) 0.2 (3.3 ) — — — Long-Term Derivative Liabilities: CL&P Level 3 (357.7 ) — (357.7 ) (379.5 ) — (379.5 ) Other Level 2 (0.2 ) — (0.2 ) — — — (1) Amounts represent derivative assets and liabilities that Eversource elected to record net on the balance sheets. These amounts are subject to master netting agreements or similar agreements for which the right of offset exists.
Summary of Level 3 Derivative Contracts and Significant Unobservable Inputs Used	The following is a summary of Level 3 derivative contracts and the range of the significant unobservable inputs utilized in the valuations over the duration of the contracts: As of September 30, 2019 As of December 31, 2018 CL&P Range Period Covered Range Period Covered Capacity Prices $ 3.01 — 7.34 per kW-Month 2023 - 2026 $ 4.30 — 7.44 per kW-Month 2022 - 2026 Forward Reserve 0.80 — 1.90 per kW-Month 2019 - 2024 0.75 — 1.78 per kW-Month 2019 - 2024
Changes in the Level 3 Category of Derivative Assets Measured at Fair Value on a Recurring Basis	The following table presents changes in the Level 3 category of derivative assets and derivative liabilities measured at fair value on a recurring basis. The derivative assets and liabilities are presented on a net basis. CL&P For the Three Months Ended September 30, For the Nine Months Ended September 30, (Millions of Dollars) 2019 2018 2019 2018 Derivatives, Net: Fair Value as of Beginning of Period $ (345.4 ) $ (369.3 ) $ (356.5 ) $ (362.3 ) Net Realized/Unrealized (Losses)/Gains Included in Regulatory Assets (8.5 ) 1.2 (16.4 ) (27.0 ) Settlements 11.6 8.2 30.6 29.4 Fair Value as of End of Period $ (342.3 ) $ (359.9 ) $ (342.3 ) $ (359.9 )

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Debt Securities	The following is a summary of the available-for-sale debt securities, which are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of September 30, 2019 As of December 31, 2018 Eversource (Millions of Dollars) Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Debt Securities $ 203.0 $ 8.9 $ (0.1 ) $ 211.8 $ 190.0 $ 0.4 $ (4.0 ) $ 186.4
Contractual Maturities of Available-for-Sale Debt Securities	As of September 30, 2019 , the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Cost Fair Value Less than one year (1) $ 28.6 $ 28.5 One to five years 49.8 51.2 Six to ten years 30.0 31.9 Greater than ten years 94.6 100.2 Total Debt Securities $ 203.0 $ 211.8 (1) Amounts in the Less than one year category include securities in the CYAPC and YAEC spent nuclear fuel trusts, which are restricted and are classified in long-term Marketable Securities on the balance sheets.
Marketable Securities Recorded at Fair Value on a Recurring Basis by Level	The following table presents the marketable securities recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Eversource (Millions of Dollars) As of September 30, 2019 As of December 31, 2018 Level 1: Mutual Funds and Equities $ 207.1 $ 244.0 Money Market Funds 19.6 25.9 Total Level 1 $ 226.7 $ 269.9 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 95.2 $ 79.6 Corporate Debt Securities 49.5 39.5 Asset-Backed Debt Securities 13.1 14.0 Municipal Bonds 25.6 19.2 Other Fixed Income Securities 8.8 8.2 Total Level 2 $ 192.2 $ 160.5 Total Marketable Securities $ 418.9 $ 430.4

SHORT-TERM AND LONG-TERM DEBT (

SHORT-TERM AND LONG-TERM DEBT (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Borrowings Outstanding and Available under the Commecrial Paper Programs	The amount of borrowings outstanding and available under the commercial paper programs were as follows: Borrowings Outstanding as of Available Borrowing Capacity as of Weighted-Average Interest Rate as of September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 (Millions of Dollars) Eversource Parent Commercial Paper Program $ 684.5 $ 631.5 $ 765.5 $ 818.5 2.25 % 2.77 % NSTAR Electric Commercial Paper Program 28.0 278.5 622.0 371.5 1.98 % 2.50 %
Summary of Long-Term Debt Issuance and Repayments	The following table summarizes long-term debt issuances and repayments: (Millions of Dollars) Issue Date Issuance/(Repayment) Maturity Date Use of Proceeds for Issuance/ CL&P: 4.00% 2018 Series A First Mortgage Bonds (1) April 2019 $ 300.0 April 2048 Paid short-term borrowings that were used to pay long-term debt that matured on February 1, 2019 and fund capital expenditures and working capital 3.20% 2017 Series A First Mortgage Bonds (2) September 2019 200.0 March 2027 Paid short-term borrowings and fund capital expenditures and working capital 5.50% 2009 Series A First Mortgage Bonds February 2009 (250.0 ) February 2019 Paid at maturity on February 1, 2019 NSTAR Electric: 3.25% 2019 Debentures May 2019 400.0 May 2029 Paid short-term borrowings that were used to fund investments in eligible green expenditures PSNH: 3.60% 2019 Series T First Mortgage Bonds June 2019 300.0 July 2049 Paid long-term debt due to mature in December 2019, paid short-term borrowings and fund capital expenditures and working capital Other: NSTAR Gas 3.74% Series Q First Mortgage Bonds July 2019 75.0 August 2049 Paid short-term borrowings and fund capital expenditures and working capital Yankee Gas 2.23% Series P First Mortgage Bonds September 2019 100.0 October 2024 Paid long-term debt due to mature in November 2019, paid short-term borrowings and fund capital expenditures and working capital Yankee Gas 3.30% Series Q First Mortgage Bonds September 2019 100.0 October 2049 Paid long-term debt due to mature in November 2019, paid short-term borrowings and fund capital expenditures and working capital (1) These bonds are part of the same series issued by CL&P in March 2018. The aggregate outstanding principal amount of these bonds is now $800 million . (2) These bonds are part of the same series issued by CL&P in March 2017. The aggregate outstanding principal amount of these bonds is now $500 million .

RATE REDUCTION BONDS AND VARI_2

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES (Tables)	9 Months Ended
	Sep. 30, 2019
Rate Reduction Bonds and Variable Interest Entity [Abstract]
Summary of the Impact of Funding on the Balance Sheets and Income Statements	The following tables summarize the impact of PSNH Funding on PSNH's balance sheets and income statements: (Millions of Dollars) Balance Sheet: As of September 30, 2019 As of December 31, 2018 Restricted Cash - Current Portion (included in Prepayments and Other Current Assets) $ 18.5 $ 47.5 Restricted Cash - Long-Term Portion (included in Other Long-Term Assets) 3.2 3.2 Securitized Stranded Costs (included in Regulatory Assets) 576.1 608.4 Other Regulatory Liabilities (included in Regulatory Liabilities) 7.7 5.8 Accrued Interest (included in Other Current Liabilities) 3.4 14.4 Rate Reduction Bonds - Current Portion 43.2 52.3 Rate Reduction Bonds - Long-Term Portion 540.1 583.3 (Millions of Dollars) For the Three Months Ended For the Nine Months Ended Income Statement: September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net) $ 10.8 $ 10.2 $ 32.2 $ 17.1 Interest Expense on RRB Principal (included in Interest Expense) 5.2 6.0 15.9 8.8

PENSION BENEFITS AND POSTRETI_2

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION (Tables)	9 Months Ended
	Sep. 30, 2019
Postemployment Benefits [Abstract]
Components of Net Periodic Benefit Expense/(Income)	The components of net periodic benefit expense/(income) for the Pension, SERP and PBOP Plans, prior to amounts capitalized as Property, Plant and Equipment or deferred as regulatory assets for future recovery, are shown below. The service cost component of net periodic benefit expense, less the capitalized portion, is included in Operations and Maintenance expense on the statements of income. The remaining components of net periodic benefit expense/(income), less the deferred portion, are included in Other Income, Net on the statements of income. Pension, SERP and PBOP expense reflected in the statements of cash flows for CL&P, NSTAR Electric and PSNH does not include the intercompany allocations or the corresponding capitalized and deferred portion, as these amounts are cash settled on a short-term basis. Pension and SERP For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 16.2 $ 4.4 $ 3.6 $ 1.5 $ 20.9 $ 5.2 $ 4.3 $ 2.7 Interest Cost 54.8 11.4 12.3 6.0 49.2 10.5 10.9 5.5 Expected Return on Pension Plan Assets (91.6 ) (18.1 ) (24.2 ) (10.1 ) (97.8 ) (19.4 ) (26.6 ) (10.8 ) Actuarial Loss 35.6 6.3 11.8 2.3 35.7 7.1 10.1 3.3 Prior Service Cost 0.3 — — — 2.0 0.2 0.1 0.1 Total Net Periodic Benefit Expense/(Income) $ 15.3 $ 4.0 $ 3.5 $ (0.3 ) $ 10.0 $ 3.6 $ (1.2 ) $ 0.8 Intercompany Allocations N/A $ 2.0 $ 1.9 $ 0.5 N/A $ 1.5 $ 1.6 $ 0.5 Pension and SERP For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 51.6 $ 13.6 $ 11.0 $ 5.6 $ 64.2 $ 16.2 $ 13.1 $ 8.4 Interest Cost 163.8 34.4 36.6 18.2 147.1 31.4 32.6 16.4 Expected Return on Pension Plan Assets (275.4 ) (55.1 ) (72.9 ) (30.6 ) (293.8 ) (59.7 ) (78.3 ) (32.6 ) Actuarial Loss 107.9 20.6 33.1 8.2 107.6 21.9 31.0 9.8 Prior Service Cost 0.9 — 0.2 — 6.0 0.8 0.2 0.2 Total Net Periodic Benefit Expense/(Income) $ 48.8 $ 13.5 $ 8.0 $ 1.4 $ 31.1 $ 10.6 $ (1.4 ) $ 2.2 Intercompany Allocations N/A $ 6.5 $ 6.1 $ 1.8 N/A $ 4.5 $ 4.8 $ 1.4 PBOP For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 2.0 $ 0.3 $ 0.4 $ 0.2 $ 2.5 $ 0.4 $ 0.5 $ 0.3 Interest Cost 8.1 1.6 2.4 0.8 7.7 1.5 2.2 0.9 Expected Return on Plan Assets (16.7 ) (2.2 ) (7.5 ) (1.3 ) (18.2 ) (2.6 ) (8.1 ) (1.5 ) Actuarial Loss 2.1 0.3 0.8 0.1 2.6 0.4 0.5 0.2 Prior Service Cost/(Credit) (5.8 ) 0.2 (4.2 ) 0.1 (6.0 ) 0.3 (4.3 ) 0.1 Total Net Periodic Benefit Expense/(Income) $ (10.3 ) $ 0.2 $ (8.1 ) $ (0.1 ) $ (11.4 ) $ — $ (9.2 ) $ — Intercompany Allocations N/A $ (0.2 ) $ (0.3 ) $ (0.1 ) N/A $ (0.3 ) $ (0.3 ) $ (0.1 ) PBOP For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 5.9 $ 1.1 $ 1.3 $ 0.5 $ 7.5 $ 1.4 $ 1.6 $ 0.9 Interest Cost 24.5 4.7 7.1 2.5 23.0 4.4 6.5 2.5 Expected Return on Plan Assets (50.1 ) (6.9 ) (22.6 ) (4.0 ) (54.2 ) (7.8 ) (24.4 ) (4.5 ) Actuarial Loss 6.2 1.0 2.5 0.3 7.7 1.2 1.7 0.6 Prior Service Cost/(Credit) (17.6 ) 0.8 (12.7 ) 0.3 (17.6 ) 0.8 (12.7 ) 0.4 Total Net Periodic Benefit Expense/(Income) $ (31.1 ) $ 0.7 $ (24.4 ) $ (0.4 ) $ (33.6 ) $ — $ (27.3 ) $ (0.1 ) Intercompany Allocations N/A $ (0.6 ) $ (0.9 ) $ (0.3 ) N/A $ (0.8 ) $ (1.0 ) $ (0.3 )

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Environmental Sites and Related Reserves	The number of environmental sites and related reserves for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: As of September 30, 2019 As of December 31, 2018 Number of Sites Reserve (in millions) Number of Sites Reserve (in millions) Eversource 58 $ 70.3 60 $ 64.7 CL&P 15 6.0 15 5.4 NSTAR Electric 15 9.5 16 10.9 PSNH 9 5.7 9 5.4
Summary of Exposure to Guarantees and Indemnifications	The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries to external parties, as of September 30, 2019 : Company Description Maximum Exposure (in millions) Expiration Dates On behalf of subsidiaries: Various Surety Bonds (1) $ 34.3 2019 - 2021 Rocky River Realty Company and Eversource Service Lease Payments for Real Estate 6.8 2024 Bay State Wind Real Estate Purchase 2.5 2020 (1) Surety bond expiration dates reflect termination dates, the majority of which will be renewed or extended. Certain surety bonds contain credit ratings triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource parent are downgraded.

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Components of Lease Cost	The components of lease cost, prior to amounts capitalized, are as follows: For the Three Months Ended September 30, 2019 For the Nine Months Ended September 30, 2019 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Financing Lease Cost: Amortization of Right-of-use-Assets $ 0.4 $ 0.2 $ 0.1 $ — $ 1.1 $ 0.6 $ 0.1 $ 0.1 Interest on Lease Liabilities 0.3 0.1 0.1 — 1.0 0.4 0.4 — Total Finance Lease Cost 0.7 0.3 0.2 — 2.1 1.0 0.5 0.1 Operating Lease Cost 2.9 0.1 0.5 — 8.9 0.3 1.3 0.1 Variable Lease Cost 15.3 3.6 — 11.7 46.4 10.1 — 36.3 Total Lease Cost $ 18.9 $ 4.0 $ 0.7 $ 11.7 $ 57.4 $ 11.4 $ 1.8 $ 36.5
Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases is as follows: As of September 30, 2019 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Operating Leases: Operating Lease Right-of-use-Assets, Net Other Long-Term Assets $ 52.3 $ 0.9 $ 24.2 $ 0.4 Operating Lease Liabilities Operating Lease Liabilities - Current Portion Other Current Liabilities $ 8.9 $ 0.5 $ 0.6 $ — Operating Lease Liabilities - Long-Term Other Long-Term Liabilities 43.4 0.4 23.6 0.4 Total Operating Lease Liabilities $ 52.3 $ 0.9 $ 24.2 $ 0.4 Finance Leases: Finance Lease Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 8.8 $ 2.2 $ 3.4 $ 0.9 Finance Lease Liabilities Finance Lease Liabilities - Current Portion Other Current Liabilities $ 2.3 $ 1.6 $ — $ 0.1 Finance Lease Liabilities - Long-Term Other Long-Term Liabilities 8.7 1.8 4.4 0.8 Total Finance Lease Liabilities $ 11.0 $ 3.4 $ 4.4 $ 0.9
Other Information Related to Leases	Other information related to leases is as follows (in millions of dollars, unless otherwise noted): Eversource CL&P NSTAR Electric PSNH As of September 30, 2019 Weighted-Average Remaining Lease Term (Years): Operating Leases 12 2 20 9 Financing Leases 11 2 22 9 Weighted-Average Discount Rate (Percentage): Operating Leases 3.9 % 2.5 % 4.1 % 3.7 % Financing Leases 4.2 % 10.5 % 2.9 % 3.5 % For the Three Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 2.9 $ 0.1 $ 0.5 $ — Operating Cash Flows from Finance Leases 0.3 0.1 0.1 — Financing Cash Flows from Finance Leases 0.5 0.4 — — Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.9 0.8 — — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities — — — — For the Nine Months Ended September 30, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 8.7 $ 0.3 $ 1.2 $ 0.1 Operating Cash Flows from Finance Leases 1.0 0.4 0.4 — Financing Cash Flows from Finance Leases 1.5 1.0 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.6 1.0 — 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 1.3 — — —
Future Minimum Lease Payments under Long-Term Leases	Future minimum lease payments, excluding variable costs, under long-term leases, as of September 30, 2019 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH October 1, 2019 through December 31, 2019 $ 2.6 $ 0.1 $ 0.3 $ — $ 0.9 $ 0.5 $ 0.1 $ — Year Ending December 31, 2020 10.1 0.5 1.6 0.1 3.4 2.0 0.5 0.1 2021 8.9 0.2 1.6 0.1 2.9 1.5 0.5 0.1 2022 7.4 — 1.6 0.1 1.5 — 0.6 0.1 2023 4.9 — 1.6 — 0.7 — 0.6 0.1 2024 2.8 — 1.6 — 0.7 — 0.6 0.1 Thereafter 28.9 0.1 28.7 0.2 13.3 — 12.8 0.5 Future lease payments 65.6 0.9 37.0 0.5 23.4 4.0 15.7 1.0 Less amount representing interest 13.3 — 12.8 0.1 12.4 0.6 11.3 0.1 Present value of future minimum lease payments $ 52.3 $ 0.9 $ 24.2 $ 0.4 $ 11.0 $ 3.4 $ 4.4 $ 0.9
Future Minimum Lease Payments under Long-Term Leases	Future minimum lease payments, excluding variable costs, under long-term leases, as of September 30, 2019 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH October 1, 2019 through December 31, 2019 $ 2.6 $ 0.1 $ 0.3 $ — $ 0.9 $ 0.5 $ 0.1 $ — Year Ending December 31, 2020 10.1 0.5 1.6 0.1 3.4 2.0 0.5 0.1 2021 8.9 0.2 1.6 0.1 2.9 1.5 0.5 0.1 2022 7.4 — 1.6 0.1 1.5 — 0.6 0.1 2023 4.9 — 1.6 — 0.7 — 0.6 0.1 2024 2.8 — 1.6 — 0.7 — 0.6 0.1 Thereafter 28.9 0.1 28.7 0.2 13.3 — 12.8 0.5 Future lease payments 65.6 0.9 37.0 0.5 23.4 4.0 15.7 1.0 Less amount representing interest 13.3 — 12.8 0.1 12.4 0.6 11.3 0.1 Present value of future minimum lease payments $ 52.3 $ 0.9 $ 24.2 $ 0.4 $ 11.0 $ 3.4 $ 4.4 $ 0.9
Future Minimum Rental Payments under Operating Leases	At December 31, 2018, future minimum rental payments, excluding executory costs, such as property taxes, state use taxes, insurance, and maintenance were as follows: Operating Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 11.5 $ 1.5 $ 7.2 $ 0.5 2020 9.8 1.4 6.0 0.4 2021 8.7 1.2 5.3 0.4 2022 7.2 1.1 4.4 0.4 2023 4.7 0.5 3.1 0.2 Thereafter 32.7 0.2 29.5 0.3 Future minimum lease payments $ 74.6 $ 5.9 $ 55.5 $ 2.2
Future Minimum Rental Payments under Capital Leases	Capital Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2019 $ 3.4 $ 2.0 $ 0.5 $ 0.1 2020 3.4 2.0 0.5 0.1 2021 2.9 1.5 0.5 0.1 2022 1.5 — 0.6 0.1 2023 0.7 — 0.6 0.1 Thereafter 13.9 — 13.4 0.5 Future minimum lease payments 25.8 5.5 16.1 1.0 Less amount representing interest 13.8 1.0 12.4 0.1 Present value of future minimum lease payments $ 12.0 $ 4.5 $ 3.7 $ 0.9

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Carrying Amounts and Estimated Fair Values of Financial Instruments	Carrying amounts and estimated fair values are as follows: Eversource CL&P NSTAR Electric PSNH (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value As of September 30, 2019: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 160.3 $ 116.2 $ 116.6 $ 43.0 $ 43.7 $ — $ — Long-Term Debt 14,293.2 15,479.2 3,518.5 4,104.4 3,341.6 3,695.3 1,101.5 1,165.7 Rate Reduction Bonds 583.3 634.1 — — — — 583.3 634.1 As of December 31, 2018: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 156.8 $ 116.2 $ 113.8 $ 43.0 $ 43.0 $ — $ — Long-Term Debt 13,086.1 13,154.9 3,254.0 3,429.2 2,944.8 3,024.1 805.2 819.5 Rate Reduction Bonds 635.7 645.8 — — — — 635.7 645.8

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income/(Loss) by Component, Net of Tax	The changes in accumulated other comprehensive income/(loss) by component, net of tax, are as follows: For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Qualified Cash Flow Hedging Instruments Unrealized Gains/(Losses) on Marketable Securities Defined Benefit Plans Total Qualified Cash Flow Hedging Instruments Unrealized Losses on Marketable Securities Defined Benefit Plans Total Balance as of January 1st $ (4.4 ) $ (0.5 ) $ (55.1 ) $ (60.0 ) $ (6.2 ) $ — $ (60.2 ) $ (66.4 ) OCI Before Reclassifications — 1.3 2.6 3.9 — (0.7 ) 2.6 1.9 Amounts Reclassified from AOCI 0.9 — 3.2 4.1 1.6 — 3.3 4.9 Net OCI 0.9 1.3 5.8 8.0 1.6 (0.7 ) 5.9 6.8 Balance as of September 30th $ (3.5 ) $ 0.8 $ (49.3 ) $ (52.0 ) $ (4.6 ) $ (0.7 ) $ (54.3 ) $ (59.6 )

COMMON SHARES (Tables)

COMMON SHARES (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Common Shares Authorized and Issued	The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric and PSNH that were authorized and issued, as well as the respective per share par values: Shares Authorized as of September 30, 2019 and December 31, 2018 Issued as of Par Value September 30, 2019 December 31, 2018 Eversource $ 5 380,000,000 339,858,402 333,878,402 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 200 200 PSNH $ 1 100,000,000 301 301

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Components of Basic and Diluted EPS	The following table sets forth the components of basic and diluted EPS: Eversource (Millions of Dollars, except share information) For the Three Months Ended For the Nine Months Ended September 30, 2019 September 30, 2018 September 30, 2019 September 30, 2018 Net Income Attributable to Common Shareholders $ 318.9 $ 289.4 $ 659.0 $ 801.7 Weighted Average Common Shares Outstanding: Basic 324,037,169 317,360,110 320,442,253 317,367,252 Dilutive Effect of: Share-Based Compensation Awards and Other 737,972 607,201 691,636 581,246 Equity Forward Sale Agreement 1,233,201 — 437,037 — Total Dilutive Effect 1,971,173 607,201 1,128,673 581,246 Diluted 326,008,342 317,967,311 321,570,926 317,948,498 Basic EPS $ 0.98 $ 0.91 $ 2.06 $ 2.53 Diluted EPS $ 0.98 $ 0.91 $ 2.05 $ 2.52

REVENUES (Tables)

REVENUES (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Operating Revenues Disaggregated by Revenue Source	The following tables present operating revenues disaggregated by revenue source: For the Three Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,041.4 $ 43.0 $ — $ 40.0 $ — $ — $ 1,124.4 Commercial 736.6 41.6 — 17.8 — (1.4 ) 794.6 Industrial 90.6 18.1 — 1.3 — (3.2 ) 106.8 Total Retail Tariff Sales Revenues 1,868.6 102.7 — 59.1 — (4.6 ) 2,025.8 Wholesale Transmission Revenues — — 365.5 — 15.4 (300.7 ) 80.2 Wholesale Market Sales Revenues 33.1 5.5 — 1.3 — — 39.9 Other Revenues from Contracts with Customers 12.3 0.5 3.1 1.7 242.7 (243.0 ) 17.3 Reserve for Revenues Subject to Refund 4.5 1.5 — (0.8 ) — — 5.2 Total Revenues from Contracts with Customers 1,918.5 110.2 368.6 61.3 258.1 (548.3 ) 2,168.4 Alternative Revenue Programs 6.7 (7.6 ) (20.9 ) 2.6 — 19.0 (0.2 ) Other Revenues (1) 6.4 0.8 0.1 0.3 — — 7.6 Total Operating Revenues $ 1,931.6 $ 103.4 $ 347.8 $ 64.2 $ 258.1 $ (529.3 ) $ 2,175.8 For the Nine Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 2,879.8 $ 402.0 $ — $ 100.5 $ — $ — $ 3,382.3 Commercial 2,002.0 254.9 — 48.1 — (3.4 ) 2,301.6 Industrial 254.0 72.5 — 3.5 — (8.7 ) 321.3 Total Retail Tariff Sales Revenues 5,135.8 729.4 — 152.1 — (12.1 ) 6,005.2 Wholesale Transmission Revenues — — 971.6 — 43.7 (811.4 ) 203.9 Wholesale Market Sales Revenues 123.9 41.6 — 3.2 — — 168.7 Other Revenues from Contracts with Customers 40.0 1.9 9.9 5.2 723.4 (725.2 ) 55.2 Reserve for Revenues Subject to Refund (1.7 ) 4.7 — (1.9 ) — — 1.1 Total Revenues from Contracts with Customers 5,298.0 777.6 981.5 158.6 767.1 (1,548.7 ) 6,434.1 Alternative Revenue Programs 15.0 — 56.1 4.2 — (50.8 ) 24.5 Other Revenues (1) 14.2 2.3 0.3 0.7 — — 17.5 Total Operating Revenues $ 5,327.2 $ 779.9 $ 1,037.9 $ 163.5 $ 767.1 $ (1,599.5 ) $ 6,476.1 For the Three Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,111.7 $ 42.8 $ — $ 41.2 $ — $ — $ 1,195.7 Commercial 789.6 40.8 — 17.9 — (1.2 ) 847.1 Industrial 98.7 18.9 — 1.3 — (2.6 ) 116.3 Total Retail Tariff Sales Revenues 2,000.0 102.5 — 60.4 — (3.8 ) 2,159.1 Wholesale Transmission Revenues — — 364.5 — 11.7 (300.2 ) 76.0 Wholesale Market Sales Revenues 48.8 11.4 — 1.3 — — 61.5 Other Revenues from Contracts with Customers 20.2 (0.5 ) 3.1 1.9 212.9 (213.5 ) 24.1 Reserve for Revenues Subject to Refund 5.2 (3.5 ) — (1.3 ) — — 0.4 Total Revenues from Contracts with Customers 2,074.2 109.9 367.6 62.3 224.6 (517.5 ) 2,321.1 Alternative Revenue Programs (51.6 ) (1.5 ) (37.0 ) 1.1 — 33.8 (55.2 ) Other Revenues 4.8 0.6 — 0.1 — — 5.5 Total Operating Revenues $ 2,027.4 $ 109.0 $ 330.6 $ 63.5 $ 224.6 $ (483.7 ) $ 2,271.4 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 2,900.4 $ 395.9 $ — $ 100.9 $ — $ — $ 3,397.2 Commercial 2,023.0 245.4 — 47.9 — (3.4 ) 2,312.9 Industrial 268.6 71.9 — 3.4 — (7.5 ) 336.4 Total Retail Tariff Sales Revenues 5,192.0 713.2 — 152.2 — (10.9 ) 6,046.5 Wholesale Transmission Revenues — — 988.9 — 34.4 (826.9 ) 196.4 Wholesale Market Sales Revenues 141.4 41.4 — 3.1 — — 185.9 Other Revenues from Contracts with Customers 54.4 (1.4 ) 9.4 5.4 658.1 (659.8 ) 66.1 Reserve for Revenues Subject to Refund (21.2 ) (11.5 ) — (3.3 ) — — (36.0 ) Total Revenues from Contracts with Customers 5,366.6 741.7 998.3 157.4 692.5 (1,497.6 ) 6,458.9 Alternative Revenue Programs (57.2 ) (3.2 ) (45.3 ) 3.7 — 41.5 (60.5 ) Other Revenues 12.4 2.0 — 0.4 — — 14.8 Total Operating Revenues $ 5,321.8 $ 740.5 $ 953.0 $ 161.5 $ 692.5 $ (1,456.1 ) $ 6,413.2 For the Three Months Ended September 30, 2019 For the Three Months Ended September 30, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 513.6 $ 374.4 $ 153.4 $ 539.6 $ 414.8 $ 157.3 Commercial 247.0 406.1 84.1 259.0 443.8 87.3 Industrial 37.4 32.4 20.8 39.4 38.0 21.3 Total Retail Tariff Sales Revenues 798.0 812.9 258.3 838.0 896.6 265.9 Wholesale Transmission Revenues 175.2 132.9 57.4 179.1 128.3 57.1 Wholesale Market Sales Revenues 13.8 14.4 4.9 13.3 18.1 17.4 Other Revenues from Contracts with Customers 9.0 3.1 4.0 9.3 10.3 4.0 Reserve for Revenues Subject to Refund — — 4.5 8.3 — (3.1 ) Total Revenues from Contracts with Customers 996.0 963.3 329.1 1,048.0 1,053.3 341.3 Alternative Revenue Programs (15.2 ) 9.8 (8.8 ) (64.3 ) (15.4 ) (8.9 ) Other Revenues (1) 4.1 1.8 0.6 2.8 1.8 0.2 Eliminations (131.0 ) (96.2 ) (40.5 ) (121.5 ) (100.2 ) (42.4 ) Total Operating Revenues $ 853.9 $ 878.7 $ 280.4 $ 865.0 $ 939.5 $ 290.2 For the Nine Months Ended September 30, 2019 For the Nine Months Ended September 30, 2018 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,426.9 $ 1,027.8 $ 425.1 $ 1,410.0 $ 1,071.6 $ 418.8 Commercial 708.4 1,058.3 236.8 702.2 1,083.8 238.4 Industrial 105.8 90.1 58.1 111.8 96.9 59.9 Total Retail Tariff Sales Revenues 2,241.1 2,176.2 720.0 2,224.0 2,252.3 717.1 Wholesale Transmission Revenues 445.9 383.1 142.6 469.8 367.7 151.4 Wholesale Market Sales Revenues 39.6 55.9 28.4 34.3 56.4 52.3 Other Revenues from Contracts with Customers 27.0 13.2 11.8 25.0 27.9 11.4 Reserve for Revenues Subject to Refund — — (1.7 ) (8.3 ) (3.7 ) (9.2 ) Total Revenues from Contracts with Customers 2,753.6 2,628.4 901.1 2,744.8 2,700.6 923.0 Alternative Revenue Programs 45.6 19.1 6.4 (68.4 ) (15.6 ) (18.5 ) Other Revenues (1) 7.9 5.2 1.4 6.5 5.1 0.8 Eliminations (363.1 ) (294.5 ) (111.1 ) (338.0 ) (289.8 ) (112.6 ) Total Operating Revenues $ 2,444.0 $ 2,358.2 $ 797.8 $ 2,344.9 $ 2,400.3 $ 792.7 (1) Other Revenues include certain fees charged to customers, which are not considered revenue from contracts with customers. Other revenues also includes lease revenues under lessor accounting guidance of $1.2 million at Eversource, $0.3 million at CL&P, and $0.7 million at NSTAR Electric for the three months ended September 30, 2019 , and $3.4 million at Eversource, $0.7 million at CL&P, and $2.0 million at NSTAR Electric for the nine months ended September 30, 2019 , respectively.

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Summary of Segment Information and Segmented Total Assets	Eversource's segment information is as follows: For the Three Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 1,931.6 $ 103.4 $ 347.8 $ 64.2 $ 258.1 $ (529.3 ) $ 2,175.8 Depreciation and Amortization (188.4 ) (16.1 ) (64.3 ) (11.1 ) (17.2 ) 0.6 (296.5 ) Other Operating Expenses (1,448.2 ) (99.3 ) (159.6 ) (25.5 ) (275.9 ) 638.4 (1,370.1 ) Operating Income/(Loss) $ 295.0 $ (12.0 ) $ 123.9 $ 27.6 $ (35.0 ) $ 109.7 $ 509.2 Interest Expense $ (53.2 ) $ (11.7 ) $ (33.6 ) $ (8.9 ) $ (41.7 ) $ 13.9 $ (135.2 ) Other Income/(Loss), Net 13.9 — 61.4 (0.2 ) 497.0 (545.1 ) 27.0 Net Income/(Loss) Attributable to Common Shareholders 197.3 (17.1 ) 107.5 17.5 435.2 (421.5 ) 318.9 For the Nine Months Ended September 30, 2019 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 5,327.2 $ 779.9 $ 1,037.9 $ 163.5 $ 767.1 $ (1,599.5 ) $ 6,476.1 Depreciation and Amortization (517.6 ) (56.0 ) (188.0 ) (35.0 ) (45.6 ) 1.7 (840.5 ) Impairment of Northern Pass Transmission — — (239.6 ) — — — (239.6 ) Other Operating Expenses (4,166.8 ) (620.4 ) (366.9 ) (75.4 ) (719.8 ) 1,708.2 (4,241.1 ) Operating Income $ 642.8 $ 103.5 $ 243.4 $ 53.1 $ 1.7 $ 110.4 $ 1,154.9 Interest Expense $ (153.3 ) $ (35.4 ) $ (94.5 ) $ (26.2 ) $ (130.3 ) $ 40.0 $ (399.7 ) Other Income, Net 44.2 1.1 78.2 0.2 813.7 (833.6 ) 103.8 Net Income Attributable to Common Shareholders 422.7 57.6 138.4 26.3 697.2 (683.2 ) 659.0 Cash Flows Used for Investments in Plant 861.0 327.8 686.7 79.9 173.6 — 2,129.0 For the Three Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 2,027.4 $ 109.0 $ 330.6 $ 63.5 $ 224.6 $ (483.7 ) $ 2,271.4 Depreciation and Amortization (206.1 ) (13.9 ) (58.3 ) (11.7 ) (12.0 ) 0.6 (301.4 ) Other Operating Expenses (1,562.2 ) (102.4 ) (96.7 ) (25.5 ) (200.9 ) 483.7 (1,504.0 ) Operating Income/(Loss) $ 259.1 $ (7.3 ) $ 175.6 $ 26.3 $ 11.7 $ 0.6 $ 466.0 Interest Expense $ (52.4 ) $ (11.3 ) $ (30.3 ) $ (8.5 ) $ (30.5 ) $ 7.8 $ (125.2 ) Other Income, Net 32.2 1.5 9.0 0.7 251.7 (278.4 ) 16.7 Net Income/(Loss) Attributable to Common Shareholders 173.8 (12.6 ) 109.5 17.6 271.1 (270.0 ) 289.4 For the Nine Months Ended September 30, 2018 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 5,321.8 $ 740.5 $ 953.0 $ 161.5 $ 692.5 $ (1,456.1 ) $ 6,413.2 Depreciation and Amortization (486.0 ) (59.6 ) (171.8 ) (34.6 ) (35.9 ) 1.7 (786.2 ) Other Operating Expenses (4,238.6 ) (585.7 ) (268.7 ) (73.9 ) (617.2 ) 1,457.0 (4,327.1 ) Operating Income $ 597.2 $ 95.2 $ 512.5 $ 53.0 $ 39.4 $ 2.6 $ 1,299.9 Interest Expense $ (152.0 ) $ (33.7 ) $ (89.9 ) $ (25.5 ) $ (94.8 ) $ 23.2 $ (372.7 ) Other Income/(Loss), Net 70.9 5.1 26.7 (0.4 ) 913.8 (915.4 ) 100.7 Net Income Attributable to Common Shareholders 379.3 50.2 329.6 26.3 905.9 (889.6 ) 801.7 Cash Flows Used for Investments in Plant 717.4 245.5 735.8 68.1 118.3 — 1,885.1 The following table summarizes Eversource's segmented total assets: Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Water Distribution Other Eliminations Total As of September 30, 2019 $ 21,999.4 $ 4,103.5 $ 10,666.9 $ 2,311.9 $ 19,137.8 $ (18,494.1 ) $ 39,725.4 As of December 31, 2018 21,389.1 3,904.9 10,285.0 2,253.0 17,874.2 (17,464.9 ) 38,241.3 For further information regarding the 2019 impairment of NPT, see Note 1C, "Summary of Significant Accounting Policies - Impairment of Northern Pass Transmission," to the financial statements.

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Thousands, customer in Millions	Jul. 19, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)utilitycustomer$ / sharesMW	Sep. 30, 2018USD ($)	Feb. 08, 2019USD ($)mi²	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
Summary of Accounting Policies [Line Items]
Number of electric, natural gas and water customers | customer				4,000,000
Operating lease liability		$ 52,300		$ 52,300
Operating lease right-of-use asset		52,300		52,300
Pre-tax impairment charge		0	$ 0	239,644	$ 0
After-tax impact of impairment charge				$ 204,400
After-tax impact of impairment charge (in dollars per share) | $ / shares				$ 0.64
Equity investment balance		861,687		$ 861,687				$ 464,286
Energy efficiency funds collected from customers to be remitted to the State of Connecticut			$ 10,700	21,400	36,100
Capital contribution				$ 374,913	$ 27,342
Northern Pass
Summary of Accounting Policies [Line Items]
Capacity required for transmission line | MW				1,090
Pre-tax impairment charge	$ 318,000
Offshore Wind Business
Summary of Accounting Policies [Line Items]
Ownership interest						50.00%
Equity investment balance		637,200		$ 637,200
Capital contribution		133,600
Revolution Wind and South Fork Wind
Summary of Accounting Policies [Line Items]
Cost of investment in unconsolidated affiliate						$ 225,000
Ownership interest						50.00%
Area of land (in square miles) | mi²						257
Bay State Wind
Summary of Accounting Policies [Line Items]
Ownership interest						50.00%
ASU 2016-02
Summary of Accounting Policies [Line Items]
Operating lease liability							$ 58,000
Operating lease right-of-use asset							58,000
NSTAR Electric
Summary of Accounting Policies [Line Items]
Operating lease liability		24,200		24,200
Operating lease right-of-use asset		24,200		24,200
NSTAR Electric | ASU 2016-02
Summary of Accounting Policies [Line Items]
Operating lease liability							25,300
Operating lease right-of-use asset							25,300
CL&P
Summary of Accounting Policies [Line Items]
Operating lease liability		900		900
Operating lease right-of-use asset		900		$ 900
Period of accounts receivable recoverable under financial or medical duress				180 days
CL&P | ASU 2016-02
Summary of Accounting Policies [Line Items]
Operating lease liability							600
Operating lease right-of-use asset							600
PSNH
Summary of Accounting Policies [Line Items]
Operating lease liability		400		$ 400
Operating lease right-of-use asset		$ 400		$ 400
PSNH | ASU 2016-02
Summary of Accounting Policies [Line Items]
Operating lease liability							600
Operating lease right-of-use asset							$ 600
Yankee Gas
Summary of Accounting Policies [Line Items]
Period of accounts receivable recoverable under financial or medical duress				90 days
Connecticut, Massachusetts and New Hampshire
Summary of Accounting Policies [Line Items]
Number of regulated utilities | utility				8

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	$ 225,500		$ 225,500		$ 212,700
Provision for Uncollectible Hardship Accounts	146,500		146,500		131,500
Bad debt expense associated with accounts receivable	14,900	$ 21,500	46,417	$ 50,720
CL&P
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	94,100		94,100		88,000
Provision for Uncollectible Hardship Accounts	77,800		77,800		71,900
Bad debt expense associated with accounts receivable	4,500	4,400	12,084	12,135
NSTAR Electric
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	80,700		80,700		74,500
Provision for Uncollectible Hardship Accounts	49,400		49,400		42,500
Bad debt expense associated with accounts receivable	7,000	9,100	18,598	20,433
PSNH
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	10,600		10,600		11,100
Provision for Uncollectible Hardship Accounts	0		0		$ 0
Bad debt expense associated with accounts receivable	$ 1,800	$ 1,600	$ 4,977	$ 4,865

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Components of Other Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Summary of Accounting Policies [Line Items]
Other income, net	$ 26,968		$ 16,718	$ 103,818	$ 100,656
Other-than-temporary impairment			32,900		32,900
Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other income, net	10,100		14,800	23,200	44,600
AFUDC Equity
Summary of Accounting Policies [Line Items]
Other income, net	10,500		12,000	34,500	32,600
Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other income, net	6,100		(27,900)	37,000	(400)
Unrealized gain associated with investment				20,400	17,600
Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other income, net	(2,800)		1,800	(2,300)	2,200
Interest Income
Summary of Accounting Policies [Line Items]
Other income, net	2,900		10,800	10,800	16,200
Gain on Sale of Property
Summary of Accounting Policies [Line Items]
Other income, net	0		5,000	200	5,000
Other
Summary of Accounting Policies [Line Items]
Other income, net	200		200	400	500
CL&P
Summary of Accounting Policies [Line Items]
Other income, net	4,831		7,098	11,564	20,722
CL&P | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other income, net	1,700		2,000	100	7,300
CL&P | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other income, net	3,600		3,300	9,400	9,400
CL&P | Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other income, net	0		0	200	0
CL&P | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other income, net	(800)		700	900	900
CL&P | Interest Income
Summary of Accounting Policies [Line Items]
Other income, net	300		900	1,100	2,900
CL&P | Gain on Sale of Property
Summary of Accounting Policies [Line Items]
Other income, net	0		0	0	0
CL&P | Other
Summary of Accounting Policies [Line Items]
Other income, net	0		200	(100)	200
NSTAR Electric
Summary of Accounting Policies [Line Items]
Other income, net	10,735		13,697	32,479	40,567
NSTAR Electric | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other income, net	5,600		9,000	18,000	26,800
NSTAR Electric | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other income, net	5,600		4,200	14,700	11,500
NSTAR Electric | Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other income, net	200		200	600	600
NSTAR Electric | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other income, net	(900)		(400)	(1,500)	600
NSTAR Electric | Interest Income
Summary of Accounting Policies [Line Items]
Other income, net	100		200	500	600
NSTAR Electric | Gain on Sale of Property
Summary of Accounting Policies [Line Items]
Other income, net	0		500	0	500
NSTAR Electric | Other
Summary of Accounting Policies [Line Items]
Other income, net	100		0	200	0
PSNH
Summary of Accounting Policies [Line Items]
Other income, net	4,634		16,095	14,640	24,253
PSNH | Deferred Storm Restoration Costs
Summary of Accounting Policies [Line Items]
Other income, net		$ 5,200	8,700	5,200	8,700
PSNH | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other income, net	1,400		2,000	3,500	6,400
PSNH | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other income, net	1,000		0	2,100	0
PSNH | Equity in Earnings/(Loss) and Impairment of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other income, net	0		0	0	0
PSNH | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other income, net	(300)		100	0	200
PSNH | Interest Income
Summary of Accounting Policies [Line Items]
Other income, net	2,500		9,600	9,000	13,300
PSNH | Gain on Sale of Property
Summary of Accounting Policies [Line Items]
Other income, net	0		4,400	0	4,400
PSNH | Other
Summary of Accounting Policies [Line Items]
Other income, net	$ 0		$ 0	$ 0	$ 0

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Gross Tax Receipts [Line Items]
Gross receipts taxes	$ 42.6	$ 43.5	$ 124	$ 122.5
CL&P
Schedule of Gross Tax Receipts [Line Items]
Gross receipts taxes	$ 39.8	$ 40.6	$ 107.8	$ 107.7

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Non-cash Investing Activities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Schedule of Supplemental Cash Flow [Line Items]
Plant additions included in accounts payable	$ 317.8	$ 303.7
CL&P
Schedule of Supplemental Cash Flow [Line Items]
Plant additions included in accounts payable	107.6	103
NSTAR Electric
Schedule of Supplemental Cash Flow [Line Items]
Plant additions included in accounts payable	79	62.5
PSNH
Schedule of Supplemental Cash Flow [Line Items]
Plant additions included in accounts payable	$ 35.8	$ 48.3

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash Balances to Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	$ 22,688	$ 108,068
Cash and Restricted Cash reported on the Statements of Cash Flows	151,880	209,324	$ 134,605	$ 85,890
Prepayments and Other Current Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	37,700	72,100
Marketable Securities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	19,600	25,900
Other Long-Term Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	71,900	3,200
CL&P
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	9,286	87,721
Cash and Restricted Cash reported on the Statements of Cash Flows	14,281	91,613	4,880	9,619
CL&P | Prepayments and Other Current Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	4,600	3,500
CL&P | Marketable Securities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	400	400
CL&P | Other Long-Term Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	0	0
NSTAR Electric
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	264	1,606
Cash and Restricted Cash reported on the Statements of Cash Flows	6,508	14,659	15,361	14,708
NSTAR Electric | Prepayments and Other Current Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	6,100	13,000
NSTAR Electric | Marketable Securities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	100	100
NSTAR Electric | Other Long-Term Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	0	0
PSNH
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	1,647	1,439
Cash and Restricted Cash reported on the Statements of Cash Flows	24,012	52,723	$ 38,166	$ 2,191
PSNH | Prepayments and Other Current Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	18,500	47,500
PSNH | Marketable Securities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	700	600
PSNH | Other Long-Term Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 3,200	$ 3,200

REGULATORY ACCOUNTING - Compone

REGULATORY ACCOUNTING - Components of Regulatory Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 4,830,800	$ 5,145,900
Less: Current Portion	538,162	514,779
Total Long-Term Regulatory Assets	4,292,560	4,631,137
Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	1,835,100	1,914,800
Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	713,400	728,600
Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	576,100	608,400
Storm Restoration Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	508,900	576,000
Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	282,700	316,000
Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	345,800	356,500
Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	335,700	348,400
Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	101,300	89,200
Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	131,800	208,000
CL&P
Regulatory Assets [Line Items]
Total Regulatory Assets	1,577,800	1,630,700
Less: Current Portion	173,339	125,155
Total Long-Term Regulatory Assets	1,404,502	1,505,488
CL&P | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	400,500	424,700
CL&P | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	460,200	454,400
CL&P | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
CL&P | Storm Restoration Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	258,900	302,600
CL&P | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	56,500	33,200
CL&P | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	342,300	356,500
CL&P | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
CL&P | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	33,800	32,300
CL&P | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	25,600	27,000
NSTAR Electric
Regulatory Assets [Line Items]
Total Regulatory Assets	1,360,300	1,438,200
Less: Current Portion	201,215	241,747
Total Long-Term Regulatory Assets	1,159,056	1,196,512
NSTAR Electric | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	542,800	544,400
NSTAR Electric | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	108,600	105,900
NSTAR Electric | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
NSTAR Electric | Storm Restoration Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	190,200	212,900
NSTAR Electric | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	121,100	169,100
NSTAR Electric | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
NSTAR Electric | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	288,300	299,100
NSTAR Electric | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	51,700	42,200
NSTAR Electric | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	57,600	64,600
PSNH
Regulatory Assets [Line Items]
Total Regulatory Assets	870,400	929,500
Less: Current Portion	78,097	67,228
Total Long-Term Regulatory Assets	792,332	862,288
PSNH | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	148,500	169,600
PSNH | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	11,400	8,300
PSNH | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	576,100	608,400
PSNH | Storm Restoration Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	59,800	60,500
PSNH | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	58,100	67,300
PSNH | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
PSNH | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
PSNH | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	3,500	3,300
PSNH | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 13,000	$ 12,100

REGULATORY ACCOUNTING - Narrati

REGULATORY ACCOUNTING - Narrative (Details) - USD ($) $ in Thousands	Jun. 27, 2019	May 01, 2019	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Apr. 17, 2019	Apr. 16, 2019	Mar. 26, 2019	Dec. 31, 2018	Nov. 16, 2018
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved			$ 144,300			$ 144,300					$ 122,900
Regulatory assets			4,830,800			4,830,800					5,145,900
Other income, net			26,968		$ 16,718	103,818	$ 100,656
CL&P
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved			44,700			44,700					42,100
Regulatory assets			1,577,800			1,577,800					1,630,700
Other income, net			4,831		7,098	11,564	20,722
CL&P | Storm Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved									$ 145,500			$ 153,000
Recovery period		6 years
Regulatory assets		$ 141,000						$ 141,000
PSNH
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved			17,800			17,800					12,200
Regulatory assets			870,400			870,400					929,500
Other income, net			4,634		16,095	14,640	24,253
PSNH | Storm Costs
Regulatory Assets [Line Items]
Recovery period	5 years
Regulatory assets	$ 68,500									$ 38,100
PSNH | Deferred Costs from Generation Asset Sale
Regulatory Assets [Line Items]
Other income, net				$ 5,200	8,700	5,200	8,700
NSTAR Electric
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved			61,500			61,500					49,300
Regulatory assets			1,360,300			1,360,300					$ 1,438,200
Other income, net			$ 10,735		$ 13,697	$ 32,479	$ 40,567

REGULATORY ACCOUNTING - Compo_2

REGULATORY ACCOUNTING - Components of Regulatory Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 4,085,700	$ 3,979,700
Less: Current Portion	441,189	370,230
Total Long-Term Regulatory Liabilities	3,644,477	3,609,475
EDIT due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	2,846,900	2,883,000
Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	552,000	521,000
Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	79,700	91,200
Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	404,300	309,000
AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	72,600	70,700
Revenue Subject to Refund due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	18,300	24,600
Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	111,900	80,200
CL&P
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,328,000	1,231,800
Less: Current Portion	168,053	109,614
Total Long-Term Regulatory Liabilities	1,159,909	1,122,157
CL&P | EDIT due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,025,700	1,031,000
CL&P | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	56,300	39,900
CL&P | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
CL&P | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	169,700	89,500
CL&P | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	46,400	47,400
CL&P | Revenue Subject to Refund due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
CL&P | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	29,900	24,000
NSTAR Electric
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,719,000	1,703,900
Less: Current Portion	199,381	190,620
Total Long-Term Regulatory Liabilities	1,519,631	1,513,279
NSTAR Electric | EDIT due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,083,200	1,103,700
NSTAR Electric | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	325,200	307,100
NSTAR Electric | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	67,400	76,900
NSTAR Electric | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	167,900	163,700
NSTAR Electric | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	26,200	23,300
NSTAR Electric | Revenue Subject to Refund due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
NSTAR Electric | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	49,100	29,200
PSNH
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	472,800	483,600
Less: Current Portion	54,681	55,526
Total Long-Term Regulatory Liabilities	418,106	428,069
PSNH | EDIT due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	394,000	396,400
PSNH | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	20,500	22,100
PSNH | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
PSNH | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	43,300	48,300
PSNH | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
PSNH | Revenue Subject to Refund due to Tax Cuts and Jobs Act
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	9,000	12,600
PSNH | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 6,000	$ 4,200

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	$ 15,737,600	$ 15,071,100
Distribution - Natural Gas	3,723,700	3,546,200
Transmission - Electric	10,570,600	10,153,900
Distribution - Water	1,686,300	1,639,800
Solar	199,200	164,100
Utility	31,917,400	30,575,100
Other	935,200	778,600
Property, Plant and Equipment, Gross	32,852,600	31,353,700
Less: Accumulated Depreciation
Utility	(7,417,600)	(7,126,200)
Other	(375,100)	(336,700)
Total Accumulated Depreciation	(7,792,700)	(7,462,900)
Property, Plant and Equipment, Net	25,059,900	23,890,800
Construction Work in Progress	1,852,000	1,719,600
Total Property, Plant and Equipment, Net	26,911,877	25,610,428
CL&P
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	6,417,900	6,176,400
Transmission - Electric	4,938,500	4,700,500
Solar	0	0
Property, Plant and Equipment, Gross	11,356,400	10,876,900
Less: Accumulated Depreciation
Total Accumulated Depreciation	(2,370,600)	(2,302,600)
Property, Plant and Equipment, Net	8,985,800	8,574,300
Construction Work in Progress	470,800	335,400
Total Property, Plant and Equipment, Net	9,456,562	8,909,701
NSTAR Electric
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	7,102,300	6,756,400
Transmission - Electric	4,186,600	4,065,900
Solar	199,200	164,100
Property, Plant and Equipment, Gross	11,488,100	10,986,400
Less: Accumulated Depreciation
Total Accumulated Depreciation	(2,860,300)	(2,702,000)
Property, Plant and Equipment, Net	8,627,800	8,284,400
Construction Work in Progress	636,400	510,300
Total Property, Plant and Equipment, Net	9,264,180	8,794,700
PSNH
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	2,257,700	2,178,600
Transmission - Electric	1,440,700	1,338,700
Solar	0	0
Property, Plant and Equipment, Gross	3,698,400	3,517,300
Less: Accumulated Depreciation
Total Accumulated Depreciation	(803,000)	(772,900)
Property, Plant and Equipment, Net	2,895,400	2,744,400
Construction Work in Progress	136,600	135,700
Total Property, Plant and Equipment, Net	$ 3,031,985	$ 2,880,073

DERIVATIVE INSTRUMENTS - Gross

DERIVATIVE INSTRUMENTS - Gross Fair Values and Net Amounts of Contracts (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current Derivative Assets | CL&P | Level 3
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	$ 11.6	$ 9.6
Netting	(0.3)	(3.4)
Net Amount Recorded as a Derivative	11.3	6.2
Current Derivative Assets | Other | Level 2
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	0	1.5
Netting	0	(0.9)
Net Amount Recorded as a Derivative	0	0.6
Long-term Derivative Assets | CL&P | Level 3
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	70.9	74.2
Netting	(2.2)	(2.3)
Net Amount Recorded as a Derivative	68.7	71.9
Current Derivative Liabilities | CL&P | Level 3
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(64.6)	(55.1)
Netting	0	0
Net Amount Recorded as a Derivative	(64.6)	(55.1)
Current Derivative Liabilities | Other | Level 2
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(3.5)	0
Netting	0.2	0
Net Amount Recorded as a Derivative	(3.3)	0
Long-Term Derivative Liabilities | CL&P | Level 3
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(357.7)	(379.5)
Netting	0	0
Net Amount Recorded as a Derivative	(357.7)	(379.5)
Long-Term Derivative Liabilities | Other | Level 2
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(0.2)	0
Netting	0	0
Net Amount Recorded as a Derivative	$ (0.2)	$ 0

DERIVATIVE INSTRUMENTS - Narrat

DERIVATIVE INSTRUMENTS - Narrative (Details) MWh in Millions, MMBTU in Millions, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)MW	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)MMBTUMWhMW	Sep. 30, 2018USD ($)	Dec. 31, 2018MMBTUMW
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts by United Illuminated Company			20.00%
Amount of power to be purchased under capacity-related contract (in MW) | MW	679		679		787
Amount of natural gas to be purchased under futures contracts | MMBTU			11.6		12.5
Gains (losses) on deferred as regulatory costs | $	$ (9.2)	$ 1.6	$ (19.5)	$ (25.8)
Level 3 | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts			2.60%
Level 3 | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts			14.10%
CL&P
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts			80.00%
Amount of energy to be purchased under renewable energy contract (mwh) | MWh			0.1

DERIVATIVE INSTRUMENTS - Summar

DERIVATIVE INSTRUMENTS - Summary of Level 3 Derivative Contracts and Significant Unobservable Inputs Used (Details) - CL&P - Level 3 - $ / KWmo	Sep. 30, 2019	Dec. 31, 2018
Capacity Prices | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	3.01	4.30
Capacity Prices | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	7.34	7.44
Forward Reserve | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	0.80	0.75
Forward Reserve | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	1.90	1.78

DERIVATIVE INSTRUMENTS - Change

DERIVATIVE INSTRUMENTS - Changes in the Level 3 Category of Derivative Assets Measured at Fair Value on a Recurring Basis (Details) - CL&P - Level 3 - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivatives, Net [Rollforward]
Fair Value as of Beginning of Period	$ (345.4)	$ (369.3)	$ (356.5)	$ (362.3)
Net Realized/Unrealized (Losses)/Gains Included in Regulatory Assets	(8.5)	1.2	(16.4)	(27)
Settlements	11.6	8.2	30.6	29.4
Fair Value as of End of Period	$ (342.3)	$ (359.9)	$ (342.3)	$ (359.9)

MARKETABLE SECURITIES - Narrati

MARKETABLE SECURITIES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale equity securities	$ 43.4		$ 43.4		$ 44
Unrealized gains recorded in other income	2.4	$ 2.4	5.7	$ 2.6
CYAPC and YAEC
Debt Securities, Available-for-sale [Line Items]
Available-for-sale equity securities	163.7		163.7		200
Marketable securities held in nuclear decommissioning trust	$ 174.7		$ 174.7		$ 143.9

MARKETABLE SECURITIES - Summary

MARKETABLE SECURITIES - Summary of Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Amortized Cost	$ 203	$ 190
Pre-Tax Unrealized Gains	8.9	0.4
Pre-Tax Unrealized Losses	(0.1)	(4)
Fair Value	$ 211.8	$ 186.4

MARKETABLE SECURITIES - Contrac

MARKETABLE SECURITIES - Contractual Maturities of Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Amortized Cost
Less than one year	$ 28.6
One to five years	49.8
Six to ten years	30
Greater than ten years	94.6
Amortized Cost	203	$ 190
Fair Value
Less than one year	28.5
One to five years	51.2
Six to ten years	31.9
Greater than ten years	100.2
Fair Value	$ 211.8	$ 186.4

MARKETABLE SECURITIES - Marketa

MARKETABLE SECURITIES - Marketable Securities Recorded at Fair Value on a Recurring Basis by Level (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 418.9	$ 430.4
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	226.7	269.9
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	192.2	160.5
Mutual Funds and Equities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	207.1	244
Money Market Funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	19.6	25.9
U.S. Government Issued Debt Securities (Agency and Treasury) | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	95.2	79.6
Corporate Debt Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	49.5	39.5
Asset-Backed Debt Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13.1	14
Municipal Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	25.6	19.2
Other Fixed Income Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 8.8	$ 8.2

SHORT-TERM AND LONG-TERM DEBT -

SHORT-TERM AND LONG-TERM DEBT - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Aug. 14, 2019	Apr. 26, 2019	Dec. 31, 2018
CL&P
Line of Credit Facility [Line Items]
Notes payable to Eversource parent	$ 173,100,000
Amount of long-term debt approved for issuance		$ 675,000,000
PSNH
Line of Credit Facility [Line Items]
Notes payable to Eversource parent	42,100,000			$ 57,000,000
Amount of long-term debt approved for issuance			$ 300,000,000
HEEC
Line of Credit Facility [Line Items]
Notes payable to Eversource parent	48,700,000
Commercial Paper | NSTAR Electric
Line of Credit Facility [Line Items]
Maximum borrowing capacity	650,000,000
Line of Credit
Line of Credit Facility [Line Items]
Amount outstanding under line of credit	0			0
Line of Credit | NSTAR Electric
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 650,000,000
Debt instrument term	5 years
Amount outstanding under line of credit	$ 0			$ 0
Eversource Parent | Commercial Paper
Line of Credit Facility [Line Items]
Maximum borrowing capacity	1,450,000,000
Eversource Parent | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,450,000,000
Debt instrument term	5 years

SHORT-TERM AND LONG-TERM DEBT_2

SHORT-TERM AND LONG-TERM DEBT - Borrowings Outstanding and Available under the Commercial Paper Programs (Details) - Commercial Paper - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Borrowings outstanding	$ 684.5	$ 631.5
Available borrowing capacity	$ 765.5	$ 818.5
Weighted-average interest rate	2.25%	2.77%
NSTAR Electric
Debt Instrument [Line Items]
Borrowings outstanding	$ 28	$ 278.5
Available borrowing capacity	$ 622	$ 371.5
Weighted-average interest rate	1.98%	2.50%

SHORT-TERM AND LONG-TERM DEBT_3

SHORT-TERM AND LONG-TERM DEBT - Summary of Long-Term Debt Issuance and Repayments (Details) - USD ($) $ in Thousands	Feb. 01, 2019	Sep. 30, 2019	Jul. 31, 2019	Jun. 30, 2019	May 31, 2019	Apr. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Feb. 01, 2009
Debt Instrument [Line Items]
Repayments							$ (250,855)	$ (860,855)
CL&P
Debt Instrument [Line Items]
Repayments							(250,000)	(300,000)
CL&P | Senior Notes | 4.00% 2018 Series A First Mortgage Bonds
Debt Instrument [Line Items]
Issuances						$ 300,000
Interest rate, stated percentage						4.00%
CL&P | Senior Notes | 4.00% 2018 Series A First Mortgage Bonds | Eversource Parent
Debt Instrument [Line Items]
Long-term debt		$ 800,000					$ 800,000
CL&P | Senior Notes | 3.20% 2017 Series A First Mortgage Bonds
Debt Instrument [Line Items]
Issuances		$ 200,000
Interest rate, stated percentage		3.20%					3.20%
CL&P | Senior Notes | 3.20% 2017 Series A First Mortgage Bonds | Eversource Parent
Debt Instrument [Line Items]
Long-term debt		$ 500,000					$ 500,000
CL&P | Senior Notes | 5.50% 2009 Series A First Mortgage Bonds
Debt Instrument [Line Items]
Repayments	$ (250,000)
Interest rate, stated percentage									5.50%
NSTAR Electric | Senior Notes | 3.25% 2019 Debentures
Debt Instrument [Line Items]
Issuances					$ 400,000
Interest rate, stated percentage					3.25%
PSNH
Debt Instrument [Line Items]
Repayments							$ 0	$ (110,000)
PSNH | Senior Notes | 3.60% 2019 Series T First Mortgage Bonds
Debt Instrument [Line Items]
Issuances				$ 300,000
Interest rate, stated percentage				3.60%
NSTAR Gas | Senior Notes | NSTAR Gas 3.74% Series Q First Mortgage Bonds
Debt Instrument [Line Items]
Issuances			$ 75,000
Interest rate, stated percentage			3.74%
NSTAR Gas | Senior Notes | Yankee Gas 2.23% Series P First Mortgage Bonds
Debt Instrument [Line Items]
Interest rate, stated percentage		2.23%					2.23%
NSTAR Gas | Senior Notes | Yankee Gas 3.30% Series Q First Mortgage Bonds
Debt Instrument [Line Items]
Interest rate, stated percentage		3.30%					3.30%
Yankee Gas | Senior Notes | Yankee Gas 2.23% Series P First Mortgage Bonds
Debt Instrument [Line Items]
Issuances		$ 100,000
Yankee Gas | Senior Notes | Yankee Gas 3.30% Series Q First Mortgage Bonds
Debt Instrument [Line Items]
Issuances		$ 100,000

RATE REDUCTION BONDS AND VARI_3

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Narrative (Details) - PSNH - Rate Reduction Bonds $ in Millions	May 08, 2018USD ($)
Debt Instrument [Line Items]
Amount of securitized rate reduction bonds issued	$ 635.7
Weighted average interest rate	3.66%

RATE REDUCTION BONDS AND VARI_4

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Summary of the Impact of Funding on the Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	$ 4,830,800	$ 5,145,900
Regulatory Liabilities	3,644,477	3,609,475
Accrued Interest (included in Other Current Liabilities)	806,839	823,006
Rate Reduction Bonds - Current Portion	43,210	52,332
Rate Reduction Bonds - Long-Term Portion	540,122	583,331
Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	576,100	608,400
Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	131,800	208,000
Prepayments and Other Current Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	37,700	72,100
Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	71,900	3,200
PSNH
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	870,400	929,500
Regulatory Liabilities	418,106	428,069
Accrued Interest (included in Other Current Liabilities)	61,260	64,046
Rate Reduction Bonds - Current Portion	43,210	52,332
Rate Reduction Bonds - Long-Term Portion	540,122	583,331
PSNH | Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	576,100	608,400
PSNH | Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	13,000	12,100
PSNH | Prepayments and Other Current Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	18,500	47,500
PSNH | Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	3,200	3,200
PSNH | VIE
Condensed Balance Sheet Statements, Captions [Line Items]
Rate Reduction Bonds - Current Portion	43,200	52,300
Rate Reduction Bonds - Long-Term Portion	540,100	583,300
PSNH | VIE | Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Costs (included in Regulatory Assets)	576,100	608,400
PSNH | VIE | Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Regulatory Liabilities	7,700	5,800
Accrued Interest (included in Other Current Liabilities)	3,400	14,400
PSNH | VIE | Prepayments and Other Current Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	18,500	47,500
PSNH | VIE | Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	$ 3,200	$ 3,200

RATE REDUCTION BONDS AND VARI_5

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Summary of the Impact of Funding on the Income Statements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Income Statements, Captions [Line Items]
Interest Expense on RRB Principal (included in Interest Expense)	$ 135,216	$ 125,201	$ 399,654	$ 372,734
PSNH
Condensed Income Statements, Captions [Line Items]
Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net)	20,421	27,357	39,944	41,318
Interest Expense on RRB Principal (included in Interest Expense)	16,378	16,593	44,654	43,977
PSNH | VIE | Rate Reduction Bonds
Condensed Income Statements, Captions [Line Items]
Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net)	10,800	10,200	32,200	17,100
Interest Expense on RRB Principal (included in Interest Expense)	$ 5,200	$ 6,000	$ 15,900	$ 8,800

PENSION BENEFITS AND POSTRETI_3

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit plans	$ 112.5	$ 183.2
PBOP
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit plans	$ 7.9	$ 5.7

PENSION BENEFITS AND POSTRETI_4

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION - Components of Net Periodic Benefit Expense/(Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension and SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	$ 16.2	$ 20.9	$ 51.6	$ 64.2
Interest Cost	54.8	49.2	163.8	147.1
Expected Return on Pension Plan Assets	(91.6)	(97.8)	(275.4)	(293.8)
Actuarial Loss	35.6	35.7	107.9	107.6
Prior Service Cost/(Credit)	0.3	2	0.9	6
Total Net Periodic Benefit Expense/(Income)	15.3	10	48.8	31.1
PBOP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	2	2.5	5.9	7.5
Interest Cost	8.1	7.7	24.5	23
Expected Return on Pension Plan Assets	(16.7)	(18.2)	(50.1)	(54.2)
Actuarial Loss	2.1	2.6	6.2	7.7
Prior Service Cost/(Credit)	(5.8)	(6)	(17.6)	(17.6)
Total Net Periodic Benefit Expense/(Income)	(10.3)	(11.4)	(31.1)	(33.6)
CL&P | Pension and SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	4.4	5.2	13.6	16.2
Interest Cost	11.4	10.5	34.4	31.4
Expected Return on Pension Plan Assets	(18.1)	(19.4)	(55.1)	(59.7)
Actuarial Loss	6.3	7.1	20.6	21.9
Prior Service Cost/(Credit)	0	0.2	0	0.8
Total Net Periodic Benefit Expense/(Income)	4	3.6	13.5	10.6
Intercompany Allocations	2	1.5	6.5	4.5
CL&P | PBOP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.3	0.4	1.1	1.4
Interest Cost	1.6	1.5	4.7	4.4
Expected Return on Pension Plan Assets	(2.2)	(2.6)	(6.9)	(7.8)
Actuarial Loss	0.3	0.4	1	1.2
Prior Service Cost/(Credit)	0.2	0.3	0.8	0.8
Total Net Periodic Benefit Expense/(Income)	0.2	0	0.7	0
Intercompany Allocations	(0.2)	(0.3)	(0.6)	(0.8)
NSTAR Electric | Pension and SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	3.6	4.3	11	13.1
Interest Cost	12.3	10.9	36.6	32.6
Expected Return on Pension Plan Assets	(24.2)	(26.6)	(72.9)	(78.3)
Actuarial Loss	11.8	10.1	33.1	31
Prior Service Cost/(Credit)	0	0.1	0.2	0.2
Total Net Periodic Benefit Expense/(Income)	3.5	(1.2)	8	(1.4)
Intercompany Allocations	1.9	1.6	6.1	4.8
NSTAR Electric | PBOP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.4	0.5	1.3	1.6
Interest Cost	2.4	2.2	7.1	6.5
Expected Return on Pension Plan Assets	(7.5)	(8.1)	(22.6)	(24.4)
Actuarial Loss	0.8	0.5	2.5	1.7
Prior Service Cost/(Credit)	(4.2)	(4.3)	(12.7)	(12.7)
Total Net Periodic Benefit Expense/(Income)	(8.1)	(9.2)	(24.4)	(27.3)
Intercompany Allocations	(0.3)	(0.3)	(0.9)	(1)
PSNH | Pension and SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	1.5	2.7	5.6	8.4
Interest Cost	6	5.5	18.2	16.4
Expected Return on Pension Plan Assets	(10.1)	(10.8)	(30.6)	(32.6)
Actuarial Loss	2.3	3.3	8.2	9.8
Prior Service Cost/(Credit)	0	0.1	0	0.2
Total Net Periodic Benefit Expense/(Income)	(0.3)	0.8	1.4	2.2
Intercompany Allocations	0.5	0.5	1.8	1.4
PSNH | PBOP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.2	0.3	0.5	0.9
Interest Cost	0.8	0.9	2.5	2.5
Expected Return on Pension Plan Assets	(1.3)	(1.5)	(4)	(4.5)
Actuarial Loss	0.1	0.2	0.3	0.6
Prior Service Cost/(Credit)	0.1	0.1	0.3	0.4
Total Net Periodic Benefit Expense/(Income)	(0.1)	0	(0.4)	(0.1)
Intercompany Allocations	$ (0.1)	$ (0.1)	$ (0.3)	$ (0.3)

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Environmental Sites and Related Reserves (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)site	Dec. 31, 2018USD ($)site
Site Contingency [Line Items]
Number of Sites | site	58	60
Reserve | $	$ 70.3	$ 64.7
CL&P
Site Contingency [Line Items]
Number of Sites | site	15	15
Reserve | $	$ 6	$ 5.4
NSTAR Electric
Site Contingency [Line Items]
Number of Sites | site	15	16
Reserve | $	$ 9.5	$ 10.9
PSNH
Site Contingency [Line Items]
Number of Sites | site	9	9
Reserve | $	$ 5.7	$ 5.4

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Environmental Matters (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Site Contingency [Line Items]
Reserve balance	$ 70.3	$ 64.7
MGP Sites
Site Contingency [Line Items]
Reserve balance	$ 56.4	$ 50.1

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Long-Term Contractual Arrangements (Details) - Milestone Nuclear Power Station MWh in Millions, $ in Millions	Mar. 15, 2019USD ($)megawatt	Dec. 28, 2018MWh
Long-term Purchase Commitment [Line Items]
Annual purchase requirement (in MWh) | MWh		9
Percent of the facility's output required to be purchased	50.00%
Nameplate capacity (in megawatts) | megawatt	2,112
Annual contractual commitments over term of contract | $	$ 360
CL&P
Long-term Purchase Commitment [Line Items]
Contract term	10 years	10 years
Percent of the facility's output required to be purchased	40.00%
UI
Long-term Purchase Commitment [Line Items]
Contract term	10 years	10 years

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Guarantees and Indemnifications (Details) - USD ($)	Oct. 25, 2019	Sep. 30, 2019
Sunrise Wind, LLC | Subsequent Event
Guarantor Obligations [Line Items]
Maximum exposure (up to)	$ 15,400,000
Ownership interest	50.00%
Guarantee of Financial Obligations of NPT
Guarantor Obligations [Line Items]
Maximum exposure (up to)		$ 25,000,000

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES - Summary of Exposure to Guarantees and Indemnifications (Details) $ in Millions	Sep. 30, 2019USD ($)
Various - Surety Bonds
Loss Contingencies [Line Items]
Maximum exposure	$ 34.3
Rocky River Realty Company and Eversource Service - Lease Payments for Real Estate
Loss Contingencies [Line Items]
Maximum exposure	6.8
Bay State Wind LLC - Real Estate Purchase
Loss Contingencies [Line Items]
Maximum exposure	$ 2.5

COMMITMENTS AND CONTINGENCIES_6

COMMITMENTS AND CONTINGENCIES - Spent Nuclear Fuel Obligations - Yankee Companies (Details) - USD ($) $ in Millions	Jun. 12, 2019	Feb. 21, 2019	May 22, 2017	Jul. 31, 2019
Loss Contingencies [Line Items]
Damages awarded	$ 0.5
Remaining damages sought		$ 1
Damages paid				$ 0.5
CYAPC, YAEC, and MYAPC
Loss Contingencies [Line Items]
Damages sought			$ 104.4
Damages awarded		103.2
CYAPC
Loss Contingencies [Line Items]
Damages awarded		40.7
YAEC
Loss Contingencies [Line Items]
Damages awarded		28.1
MYAPC
Loss Contingencies [Line Items]
Damages awarded		$ 34.4

COMMITMENTS AND CONTINGENCIES_7

COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints (Details) - USD ($) $ in Millions	Apr. 29, 2016	Oct. 16, 2014	Sep. 30, 2019	Oct. 15, 2014
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified			10.41%
Percentage of incentive cap on total ROE			13.08%
Minimum
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified			9.60%
Maximum
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified			10.99%
FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Base ROE subsequently authorized			11.14%
FERC ROE First, Second and Third Complaints | Minimum
Loss Contingencies [Line Items]
Percentage of maximum ROE for any incentive project				11.14%
FERC ROE First, Second and Third Complaints | Maximum
Loss Contingencies [Line Items]
Percentage of maximum ROE for any incentive project				13.10%
FERC ROE Complaints
Loss Contingencies [Line Items]
Period of complaint			15 months
Basis point change			0.10%
Estimate of possible loss for each 10 basis point change to base ROE			$ 3
FERC ROE Fourth Complaint
Loss Contingencies [Line Items]
Base ROE percentage of complaint period	10.57%
Maximum percentage cap of ROE for incentive projects	11.74%
FERC ROE First Complaint
Loss Contingencies [Line Items]
Base ROE subsequently authorized		10.57%
Percentage of maximum ROE for any incentive project		11.74%
Amounts associated with first complaint refunded			38.9
FERC ROE First Complaint | CL&P
Loss Contingencies [Line Items]
Amounts associated with first complaint refunded			22.4
FERC ROE First Complaint | NSTAR Electric
Loss Contingencies [Line Items]
Amounts associated with first complaint refunded			13.7
FERC ROE First Complaint | PSNH
Loss Contingencies [Line Items]
Amounts associated with first complaint refunded			$ 2.8
FERC ROE Second Complaint
Loss Contingencies [Line Items]
Base ROE percentage of complaint period			10.57%
Percentage of maximum ROE for any incentive project			11.74%
Loss contingency, estimate of possible earnings impact			$ 39.1
FERC ROE Second Complaint | CL&P
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			21.4
FERC ROE Second Complaint | NSTAR Electric
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			14.6
FERC ROE Second Complaint | PSNH
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			$ 3.1

COMMITMENTS AND CONTINGENCIES_8

COMMITMENTS AND CONTINGENCIES - Eversource and NSTAR Electric Boston Harbor Civil Action (Details) $ in Millions	Jul. 15, 2016USD ($)kV	Dec. 31, 2018USD ($)	Sep. 30, 2019USD ($)
Loss Contingencies [Line Items]
Amount of capacity required for installation of distribution cable (in kV) | kV	115
NSTAR Electric
Loss Contingencies [Line Items]
Base rate credit for new cable	$ 17.5	$ 17.5
Other Long-Term Liabilities
Loss Contingencies [Line Items]
Asset Retirement Obligation			$ 32
Other Long-Term Liabilities | NSTAR Electric
Loss Contingencies [Line Items]
Asset Retirement Obligation			$ 32

LEASES - Narrative (Details)

LEASES - Narrative (Details)	9 Months Ended
	Sep. 30, 2019
Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
CL&P | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
CL&P | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
NSTAR Electric | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
NSTAR Electric | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
PSNH | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
PSNH | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years

LEASES - Components of Lease Co

LEASES - Components of Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Financing Lease Cost:
Amortization of Right-of-use-Assets	$ 0.4	$ 1.1
Interest on Lease Liabilities	0.3	1
Total Finance Lease Cost	0.7	2.1
Operating Lease Cost	2.9	8.9
Variable Lease Cost	15.3	46.4
Total Lease Cost	18.9	57.4
CL&P
Financing Lease Cost:
Amortization of Right-of-use-Assets	0.2	0.6
Interest on Lease Liabilities	0.1	0.4
Total Finance Lease Cost	0.3	1
Operating Lease Cost	0.1	0.3
Variable Lease Cost	3.6	10.1
Total Lease Cost	4	11.4
NSTAR Electric
Financing Lease Cost:
Amortization of Right-of-use-Assets	0.1	0.1
Interest on Lease Liabilities	0.1	0.4
Total Finance Lease Cost	0.2	0.5
Operating Lease Cost	0.5	1.3
Variable Lease Cost	0	0
Total Lease Cost	0.7	1.8
PSNH
Financing Lease Cost:
Amortization of Right-of-use-Assets	0	0.1
Interest on Lease Liabilities	0	0
Total Finance Lease Cost	0	0.1
Operating Lease Cost	0	0.1
Variable Lease Cost	11.7	36.3
Total Lease Cost	$ 11.7	$ 36.5

LEASES - Supplemental Balance S

LEASES - Supplemental Balance Sheet Information Related to Leases (Details) $ in Millions	Sep. 30, 2019USD ($)
Operating Leases:
Operating Lease Right-of-use-Assets, Net	$ 52.3
Operating Lease Liabilities - Current Portion	8.9
Operating Lease Liabilities - Long-Term	43.4
Total Operating Lease Liabilities	52.3
Finance Leases:
Finance Lease Right-of-use-Assets, Net	8.8
Finance Lease Liabilities - Current Portion	2.3
Finance Lease Liabilities - Long-Term	8.7
Total Finance Lease Liabilities	11
CL&P
Operating Leases:
Operating Lease Right-of-use-Assets, Net	0.9
Operating Lease Liabilities - Current Portion	0.5
Operating Lease Liabilities - Long-Term	0.4
Total Operating Lease Liabilities	0.9
Finance Leases:
Finance Lease Right-of-use-Assets, Net	2.2
Finance Lease Liabilities - Current Portion	1.6
Finance Lease Liabilities - Long-Term	1.8
Total Finance Lease Liabilities	3.4
NSTAR Electric
Operating Leases:
Operating Lease Right-of-use-Assets, Net	24.2
Operating Lease Liabilities - Current Portion	0.6
Operating Lease Liabilities - Long-Term	23.6
Total Operating Lease Liabilities	24.2
Finance Leases:
Finance Lease Right-of-use-Assets, Net	3.4
Finance Lease Liabilities - Current Portion	0
Finance Lease Liabilities - Long-Term	4.4
Total Finance Lease Liabilities	4.4
PSNH
Operating Leases:
Operating Lease Right-of-use-Assets, Net	0.4
Operating Lease Liabilities - Current Portion	0
Operating Lease Liabilities - Long-Term	0.4
Total Operating Lease Liabilities	0.4
Finance Leases:
Finance Lease Right-of-use-Assets, Net	0.9
Finance Lease Liabilities - Current Portion	0.1
Finance Lease Liabilities - Long-Term	0.8
Total Finance Lease Liabilities	$ 0.9

LEASES - Other Information Rela

LEASES - Other Information Related to Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Weighted-Average Remaining Lease Term:
Operating Leases	12 years	12 years
Financing Leases	11 years	11 years
Weighted-Average Discount Rate:
Operating Leases	3.90%	3.90%
Financing Leases	4.20%	4.20%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 2.9	$ 8.7
Operating Cash Flows from Finance Leases	0.3	1
Financing Cash Flows from Finance Leases	0.5	1.5
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0.9	2.6
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 1.3
CL&P
Weighted-Average Remaining Lease Term:
Operating Leases	2 years	2 years
Financing Leases	2 years	2 years
Weighted-Average Discount Rate:
Operating Leases	2.50%	2.50%
Financing Leases	10.50%	10.50%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 0.1	$ 0.3
Operating Cash Flows from Finance Leases	0.1	0.4
Financing Cash Flows from Finance Leases	0.4	1
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0.8	1
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0
NSTAR Electric
Weighted-Average Remaining Lease Term:
Operating Leases	20 years	20 years
Financing Leases	22 years	22 years
Weighted-Average Discount Rate:
Operating Leases	4.10%	4.10%
Financing Leases	2.90%	2.90%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 0.5	$ 1.2
Operating Cash Flows from Finance Leases	0.1	0.4
Financing Cash Flows from Finance Leases	0	0
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0	0
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0
PSNH
Weighted-Average Remaining Lease Term:
Operating Leases	9 years	9 years
Financing Leases	9 years	9 years
Weighted-Average Discount Rate:
Operating Leases	3.70%	3.70%
Financing Leases	3.50%	3.50%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 0	$ 0.1
Operating Cash Flows from Finance Leases	0	0
Financing Cash Flows from Finance Leases	0	0.1
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0	0.2
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0

LEASES - Future Minimum Lease P

LEASES - Future Minimum Lease Payments under Long-Term Leases (Details) $ in Millions	Sep. 30, 2019USD ($)
Operating Leases
October 1, 2019 through December 31, 2019	$ 2.6
Year Ending December 31,
2020	10.1
2021	8.9
2022	7.4
2023	4.9
2024	2.8
Thereafter	28.9
Future lease payments	65.6
Less amount representing interest	13.3
Present value of future minimum lease payments	52.3
Finance Leases
October 1, 2019 through December 31, 2019	0.9
Year Ending December 31,
2020	3.4
2021	2.9
2022	1.5
2023	0.7
2024	0.7
Thereafter	13.3
Future lease payments	23.4
Less amount representing interest	12.4
Present value of future minimum lease payments	11
CL&P
Operating Leases
October 1, 2019 through December 31, 2019	0.1
Year Ending December 31,
2020	0.5
2021	0.2
2022	0
2023	0
2024	0
Thereafter	0.1
Future lease payments	0.9
Less amount representing interest	0
Present value of future minimum lease payments	0.9
Finance Leases
October 1, 2019 through December 31, 2019	0.5
Year Ending December 31,
2020	2
2021	1.5
2022	0
2023	0
2024	0
Thereafter	0
Future lease payments	4
Less amount representing interest	0.6
Present value of future minimum lease payments	3.4
NSTAR Electric
Operating Leases
October 1, 2019 through December 31, 2019	0.3
Year Ending December 31,
2020	1.6
2021	1.6
2022	1.6
2023	1.6
2024	1.6
Thereafter	28.7
Future lease payments	37
Less amount representing interest	12.8
Present value of future minimum lease payments	24.2
Finance Leases
October 1, 2019 through December 31, 2019	0.1
Year Ending December 31,
2020	0.5
2021	0.5
2022	0.6
2023	0.6
2024	0.6
Thereafter	12.8
Future lease payments	15.7
Less amount representing interest	11.3
Present value of future minimum lease payments	4.4
PSNH
Operating Leases
October 1, 2019 through December 31, 2019	0
Year Ending December 31,
2020	0.1
2021	0.1
2022	0.1
2023	0
2024	0
Thereafter	0.2
Future lease payments	0.5
Less amount representing interest	0.1
Present value of future minimum lease payments	0.4
Finance Leases
October 1, 2019 through December 31, 2019	0
Year Ending December 31,
2020	0.1
2021	0.1
2022	0.1
2023	0.1
2024	0.1
Thereafter	0.5
Future lease payments	1
Less amount representing interest	0.1
Present value of future minimum lease payments	$ 0.9

LEASES - Future Minimum Rental

LEASES - Future Minimum Rental Payments under Operating Leases (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
2019	$ 11.5
2020	9.8
2021	8.7
2022	7.2
2023	4.7
Thereafter	32.7
Future minimum lease payments	74.6
CL&P
Operating Leased Assets [Line Items]
2019	1.5
2020	1.4
2021	1.2
2022	1.1
2023	0.5
Thereafter	0.2
Future minimum lease payments	5.9
NSTAR Electric
Operating Leased Assets [Line Items]
2019	7.2
2020	6
2021	5.3
2022	4.4
2023	3.1
Thereafter	29.5
Future minimum lease payments	55.5
PSNH
Operating Leased Assets [Line Items]
2019	0.5
2020	0.4
2021	0.4
2022	0.4
2023	0.2
Thereafter	0.3
Future minimum lease payments	$ 2.2

LEASES - Future Minimum Renta_2

LEASES - Future Minimum Rental Payments under Capital Leases (Details) $ in Millions	Dec. 31, 2018USD ($)
Capital Leased Assets [Line Items]
2019	$ 3.4
2020	3.4
2021	2.9
2022	1.5
2023	0.7
Thereafter	13.9
Future minimum lease payments	25.8
Less amount representing interest	13.8
Present value of future minimum lease payments	12
CL&P
Capital Leased Assets [Line Items]
2019	2
2020	2
2021	1.5
2022	0
2023	0
Thereafter	0
Future minimum lease payments	5.5
Less amount representing interest	1
Present value of future minimum lease payments	4.5
NSTAR Electric
Capital Leased Assets [Line Items]
2019	0.5
2020	0.5
2021	0.5
2022	0.6
2023	0.6
Thereafter	13.4
Future minimum lease payments	16.1
Less amount representing interest	12.4
Present value of future minimum lease payments	3.7
PSNH
Capital Leased Assets [Line Items]
2019	0.1
2020	0.1
2021	0.1
2022	0.1
2023	0.1
Thereafter	0.5
Future minimum lease payments	1
Less amount representing interest	0.1
Present value of future minimum lease payments	$ 0.9

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	$ 155,570	$ 155,570
Rate Reduction Bonds	540,122	583,331
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	155,600	155,600
Long-Term Debt	14,293,200	13,086,100
Rate Reduction Bonds	583,300	635,700
Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	160,300	156,800
Long-Term Debt	15,479,200	13,154,900
Rate Reduction Bonds	634,100	645,800
CL&P
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,200	116,200
CL&P | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,200	116,200
Long-Term Debt	3,518,500	3,254,000
Rate Reduction Bonds	0	0
CL&P | Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,600	113,800
Long-Term Debt	4,104,400	3,429,200
Rate Reduction Bonds	0	0
NSTAR Electric
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,000	43,000
NSTAR Electric | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,000	43,000
Long-Term Debt	3,341,600	2,944,800
Rate Reduction Bonds	0	0
NSTAR Electric | Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,700	43,000
Long-Term Debt	3,695,300	3,024,100
Rate Reduction Bonds	0	0
PSNH
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Rate Reduction Bonds	540,122	583,331
PSNH | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	1,101,500	805,200
Rate Reduction Bonds	583,300	635,700
PSNH | Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	1,165,700	819,500
Rate Reduction Bonds	$ 634,100	$ 645,800

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent [Roll Forward]
OCI Before Reclassifications							$ 3,900	$ 1,900
Amounts Reclassified from AOCI							4,100	4,900
Other Comprehensive Income (Loss), Net of Tax	$ 1,624	$ 4,163	$ 2,196	$ 1,406	$ 2,142	$ 3,273	7,983	6,821
Total
AOCI Attributable to Parent [Roll Forward]
Balance			(60,000)			(66,400)	(60,000)	(66,400)
Other Comprehensive Income (Loss), Net of Tax	1,624	$ 4,163	2,196	1,406	$ 2,142	3,273
Balance	(52,000)			(59,600)			(52,000)	(59,600)
Qualified Cash Flow Hedging Instruments
AOCI Attributable to Parent [Roll Forward]
Balance			(4,400)			(6,200)	(4,400)	(6,200)
OCI Before Reclassifications							0	0
Amounts Reclassified from AOCI							900	1,600
Other Comprehensive Income (Loss), Net of Tax							900	1,600
Balance	(3,500)			(4,600)			(3,500)	(4,600)
Unrealized Gains/(Losses) on Marketable Securities
AOCI Attributable to Parent [Roll Forward]
Balance			(500)			0	(500)	0
OCI Before Reclassifications							1,300	(700)
Amounts Reclassified from AOCI							0	0
Other Comprehensive Income (Loss), Net of Tax							1,300	(700)
Balance	800			(700)			800	(700)
Defined Benefit Plans
AOCI Attributable to Parent [Roll Forward]
Balance			$ (55,100)			$ (60,200)	(55,100)	(60,200)
OCI Before Reclassifications							2,600	2,600
Amounts Reclassified from AOCI							3,200	3,300
Other Comprehensive Income (Loss), Net of Tax							5,800	5,900
Balance	$ (49,300)			$ (54,300)			$ (49,300)	$ (54,300)

COMMON SHARES - Common Shares A

COMMON SHARES - Common Shares Authorized and Issued (Details) - $ / shares	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Per value (in dollars per share)	$ 5	$ 5
Authorized (in shares)	380,000,000		380,000,000
Issued (in shares)	339,858,402		333,878,402
CL&P
Class of Stock [Line Items]
Per value (in dollars per share)	$ 10
Authorized (in shares)	24,500,000		24,500,000
Issued (in shares)	6,035,205		6,035,205
NSTAR Electric
Class of Stock [Line Items]
Per value (in dollars per share)	$ 1
Authorized (in shares)	100,000,000		100,000,000
Issued (in shares)	200		200
PSNH
Class of Stock [Line Items]
Per value (in dollars per share)	$ 1
Authorized (in shares)	100,000,000		100,000,000
Issued (in shares)	301		301

COMMON SHARES - Narrative (Deta

COMMON SHARES - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 04, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Equity [Abstract]
Equity offering (in shares)	17,940,000
Common shares issued directly by the Company (in shares)	5,980,000
Common shares issuable pursuant to forward sale agreement (in shares)	11,960,000
Net proceeds from common shares issued directly by the Company	$ 426,900	$ 426,902	$ 0
Forward sale price (in dollars per share)	$ 71.48
Amount that would have been required to be paid if net settled		$ 169,700
Shares that would have been required to be delivered if net settled (in shares)		1,985,105
Treasury stock (in shares)		16,124,979		16,992,594
Common stock outstanding (in shares)		323,733,423		316,885,808

COMMON SHAREHOLDERS' EQUITY A_2

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Equity [Abstract]
Dividends on preferred stock	$ 1,880	$ 1,880	$ 1,880	$ 1,880	$ 1,880	$ 1,880	$ 5,600	$ 5,600
Noncontrolling interest attributed to preferred stock of subsidiaries	$ 155,570						$ 155,570		$ 155,570

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income Attributable to Common Shareholders	$ 318,884	$ 289,380	$ 659,016	$ 801,693
Weighted Average Common Shares Outstanding:
Basic (in shares)	324,037,169	317,360,110	320,442,253	317,367,252
Dilutive Effect of:
Share-Based Compensation Awards and Other (in shares)	737,972	607,201	691,636	581,246
Equity Forward Sale Agreement (in shares)	1,233,201	0	437,037	0
Dilutive Effect (in shares)	1,971,173	607,201	1,128,673	581,246
Diluted (in shares)	326,008,342	317,967,311	321,570,926	317,948,498
Basic EPS (in dollars per share)	$ 0.98	$ 0.91	$ 2.06	$ 2.53
Diluted EPS (in dollars per share)	$ 0.98	$ 0.91	$ 2.05	$ 2.52

REVENUES (Details)

REVENUES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 2,168,400	$ 2,321,100	$ 6,434,100	$ 6,458,900
Alternative Revenue Programs	(200)	(55,200)	24,500	(60,500)
Other Revenues	7,600	5,500	17,500	14,800
Operating Revenues	2,175,797	2,271,425	6,476,084	6,413,243
Lease revenue	1,200		3,400
Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,124,400	1,195,700	3,382,300	3,397,200
Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	794,600	847,100	2,301,600	2,312,900
Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	106,800	116,300	321,300	336,400
Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	2,025,800	2,159,100	6,005,200	6,046,500
Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	80,200	76,000	203,900	196,400
Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	39,900	61,500	168,700	185,900
Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	17,300	24,100	55,200	66,100
Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	5,200	400	1,100	(36,000)
Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers
Operating Revenues
Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers
Other
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	258,100	224,600	767,100	692,500
Alternative Revenue Programs	0	0	0	0
Other Revenues	0	0	0	0
Operating Revenues	258,100	224,600	767,100	692,500
Other | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Other | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Other | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Other | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Other | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	15,400	11,700	43,700	34,400
Other | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Other | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	242,700	212,900	723,400	658,100
Other | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(548,300)	(517,500)	(1,548,700)	(1,497,600)
Alternative Revenue Programs	19,000	33,800	(50,800)	41,500
Other Revenues	0	0	0	0
Operating Revenues	(529,300)	(483,700)	(1,599,500)	(1,456,100)
Eliminations | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Eliminations | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(1,400)	(1,200)	(3,400)	(3,400)
Eliminations | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(3,200)	(2,600)	(8,700)	(7,500)
Eliminations | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(4,600)	(3,800)	(12,100)	(10,900)
Eliminations | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(300,700)	(300,200)	(811,400)	(826,900)
Eliminations | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Eliminations | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(243,000)	(213,500)	(725,200)	(659,800)
Eliminations | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Distribution | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,918,500	2,074,200	5,298,000	5,366,600
Alternative Revenue Programs	6,700	(51,600)	15,000	(57,200)
Other Revenues	6,400	4,800	14,200	12,400
Operating Revenues	1,931,600	2,027,400	5,327,200	5,321,800
Electric Distribution | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,041,400	1,111,700	2,879,800	2,900,400
Electric Distribution | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	736,600	789,600	2,002,000	2,023,000
Electric Distribution | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	90,600	98,700	254,000	268,600
Electric Distribution | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,868,600	2,000,000	5,135,800	5,192,000
Electric Distribution | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Distribution | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	33,100	48,800	123,900	141,400
Electric Distribution | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	12,300	20,200	40,000	54,400
Electric Distribution | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,500	5,200	(1,700)	(21,200)
Natural Gas Distribution | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	110,200	109,900	777,600	741,700
Alternative Revenue Programs	(7,600)	(1,500)	0	(3,200)
Other Revenues	800	600	2,300	2,000
Operating Revenues	103,400	109,000	779,900	740,500
Natural Gas Distribution | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	43,000	42,800	402,000	395,900
Natural Gas Distribution | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	41,600	40,800	254,900	245,400
Natural Gas Distribution | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	18,100	18,900	72,500	71,900
Natural Gas Distribution | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	102,700	102,500	729,400	713,200
Natural Gas Distribution | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Natural Gas Distribution | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	5,500	11,400	41,600	41,400
Natural Gas Distribution | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	500	(500)	1,900	(1,400)
Natural Gas Distribution | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,500	(3,500)	4,700	(11,500)
Electric Transmission | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	368,600	367,600	981,500	998,300
Alternative Revenue Programs	(20,900)	(37,000)	56,100	(45,300)
Other Revenues	100	0	300	0
Operating Revenues	347,800	330,600	1,037,900	953,000
Electric Transmission | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Transmission | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Transmission | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Transmission | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Transmission | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	365,500	364,500	971,600	988,900
Electric Transmission | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Electric Transmission | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,100	3,100	9,900	9,400
Electric Transmission | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Water Distribution | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	61,300	62,300	158,600	157,400
Alternative Revenue Programs	2,600	1,100	4,200	3,700
Other Revenues	300	100	700	400
Operating Revenues	64,200	63,500	163,500	161,500
Water Distribution | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	40,000	41,200	100,500	100,900
Water Distribution | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	17,800	17,900	48,100	47,900
Water Distribution | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,300	1,300	3,500	3,400
Water Distribution | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	59,100	60,400	152,100	152,200
Water Distribution | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	0
Water Distribution | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,300	1,300	3,200	3,100
Water Distribution | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,700	1,900	5,200	5,400
Water Distribution | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(800)	(1,300)	(1,900)	(3,300)
CL&P
Disaggregation of Revenue [Line Items]
Operating Revenues	853,943	865,028	2,444,034	2,344,903
Lease revenue	300		700
CL&P | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	996,000	1,048,000	2,753,600	2,744,800
Alternative Revenue Programs	(15,200)	(64,300)	45,600	(68,400)
Other Revenues	4,100	2,800	7,900	6,500
CL&P | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	513,600	539,600	1,426,900	1,410,000
CL&P | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	247,000	259,000	708,400	702,200
CL&P | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	37,400	39,400	105,800	111,800
CL&P | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	798,000	838,000	2,241,100	2,224,000
CL&P | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	175,200	179,100	445,900	469,800
CL&P | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	13,800	13,300	39,600	34,300
CL&P | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	9,000	9,300	27,000	25,000
CL&P | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	8,300	0	(8,300)
CL&P | Eliminations
Disaggregation of Revenue [Line Items]
Operating Revenues	(131,000)	(121,500)	(363,100)	(338,000)
NSTAR Electric
Disaggregation of Revenue [Line Items]
Operating Revenues	878,669	939,460	2,358,174	2,400,324
Lease revenue	700		2,000
NSTAR Electric | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	963,300	1,053,300	2,628,400	2,700,600
Alternative Revenue Programs	9,800	(15,400)	19,100	(15,600)
Other Revenues	1,800	1,800	5,200	5,100
NSTAR Electric | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	374,400	414,800	1,027,800	1,071,600
NSTAR Electric | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	406,100	443,800	1,058,300	1,083,800
NSTAR Electric | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	32,400	38,000	90,100	96,900
NSTAR Electric | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	812,900	896,600	2,176,200	2,252,300
NSTAR Electric | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	132,900	128,300	383,100	367,700
NSTAR Electric | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	14,400	18,100	55,900	56,400
NSTAR Electric | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,100	10,300	13,200	27,900
NSTAR Electric | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0	(3,700)
NSTAR Electric | Eliminations
Disaggregation of Revenue [Line Items]
Operating Revenues	(96,200)	(100,200)	(294,500)	(289,800)
PSNH
Disaggregation of Revenue [Line Items]
Operating Revenues	280,431	290,203	797,766	792,700
PSNH | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	329,100	341,300	901,100	923,000
Alternative Revenue Programs	(8,800)	(8,900)	6,400	(18,500)
Other Revenues	600	200	1,400	800
PSNH | Operating Segments | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	153,400	157,300	425,100	418,800
PSNH | Operating Segments | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	84,100	87,300	236,800	238,400
PSNH | Operating Segments | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	20,800	21,300	58,100	59,900
PSNH | Operating Segments | Total Retail Tariff Sale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	258,300	265,900	720,000	717,100
PSNH | Operating Segments | Transmission Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	57,400	57,100	142,600	151,400
PSNH | Operating Segments | Wholesale Revenue
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,900	17,400	28,400	52,300
PSNH | Operating Segments | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,000	4,000	11,800	11,400
PSNH | Operating Segments | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,500	(3,100)	(1,700)	(9,200)
PSNH | Eliminations
Disaggregation of Revenue [Line Items]
Operating Revenues	$ (40,500)	$ (42,400)	$ (111,100)	$ (112,600)

SEGMENT INFORMATION - Narrative

SEGMENT INFORMATION - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)segmentcompany
Segment Reporting Information [Line Items]
Number of companies that transmit hydro electricity imported from The Hydro-Quebec System in Canada | company	2
CL&P
Segment Reporting Information [Line Items]
Number of reportable segments	1
NSTAR Electric
Segment Reporting Information [Line Items]
Number of reportable segments	1
PSNH
Segment Reporting Information [Line Items]
Number of reportable segments	1
Affiliated Entity
Segment Reporting Information [Line Items]
Affiliate transaction costs classified as Purchased Power, Fuel and Transmission Costs | $	$ 62.5

SEGMENT INFORMATION - Summary o

SEGMENT INFORMATION - Summary of Segment Information and Segmented Total Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating Revenues	$ 2,175,797	$ 2,271,425	$ 6,476,084	$ 6,413,243
Depreciation and Amortization	(296,500)	(301,400)	(840,500)	(786,200)
Impairment of Northern Pass Transmission	0	0	(239,644)	0
Other Operating Expenses	(1,370,100)	(1,504,000)	(4,241,100)	(4,327,100)
Operating Income/(Loss)	509,238	466,021	1,154,926	1,299,907
Interest Expense	(135,216)	(125,201)	(399,654)	(372,734)
Other Income/(Loss), Net	26,968	16,718	103,818	100,656
Net Income/(Loss) Attributable to Common Shareholders	318,884	289,380	659,016	801,693
Cash Flows Used for Investments in Plant			2,129,037	1,885,081
Assets	39,725,394		39,725,394		$ 38,241,256
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues
Other
Segment Reporting Information [Line Items]
Operating Revenues	258,100	224,600	767,100	692,500
Depreciation and Amortization	(17,200)	(12,000)	(45,600)	(35,900)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(275,900)	(200,900)	(719,800)	(617,200)
Operating Income/(Loss)	(35,000)	11,700	1,700	39,400
Interest Expense	(41,700)	(30,500)	(130,300)	(94,800)
Other Income/(Loss), Net	497,000	251,700	813,700	913,800
Net Income/(Loss) Attributable to Common Shareholders	435,200	271,100	697,200	905,900
Cash Flows Used for Investments in Plant			173,600	118,300
Assets	19,137,800		19,137,800		17,874,200
Eliminations
Segment Reporting Information [Line Items]
Operating Revenues	(529,300)	(483,700)	(1,599,500)	(1,456,100)
Depreciation and Amortization	600	600	1,700	1,700
Impairment of Northern Pass Transmission			0
Other Operating Expenses	638,400	483,700	1,708,200	1,457,000
Operating Income/(Loss)	109,700	600	110,400	2,600
Interest Expense	13,900	7,800	40,000	23,200
Other Income/(Loss), Net	(545,100)	(278,400)	(833,600)	(915,400)
Net Income/(Loss) Attributable to Common Shareholders	(421,500)	(270,000)	(683,200)	(889,600)
Cash Flows Used for Investments in Plant			0	0
Assets	(18,494,100)		(18,494,100)		(17,464,900)
Electric Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	1,931,600	2,027,400	5,327,200	5,321,800
Depreciation and Amortization	(188,400)	(206,100)	(517,600)	(486,000)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(1,448,200)	(1,562,200)	(4,166,800)	(4,238,600)
Operating Income/(Loss)	295,000	259,100	642,800	597,200
Interest Expense	(53,200)	(52,400)	(153,300)	(152,000)
Other Income/(Loss), Net	13,900	32,200	44,200	70,900
Net Income/(Loss) Attributable to Common Shareholders	197,300	173,800	422,700	379,300
Cash Flows Used for Investments in Plant			861,000	717,400
Assets	21,999,400		21,999,400		21,389,100
Natural Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	103,400	109,000	779,900	740,500
Depreciation and Amortization	(16,100)	(13,900)	(56,000)	(59,600)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(99,300)	(102,400)	(620,400)	(585,700)
Operating Income/(Loss)	(12,000)	(7,300)	103,500	95,200
Interest Expense	(11,700)	(11,300)	(35,400)	(33,700)
Other Income/(Loss), Net	0	1,500	1,100	5,100
Net Income/(Loss) Attributable to Common Shareholders	(17,100)	(12,600)	57,600	50,200
Cash Flows Used for Investments in Plant			327,800	245,500
Assets	4,103,500		4,103,500		3,904,900
Electric Transmission | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	347,800	330,600	1,037,900	953,000
Depreciation and Amortization	(64,300)	(58,300)	(188,000)	(171,800)
Impairment of Northern Pass Transmission			(239,600)
Other Operating Expenses	(159,600)	(96,700)	(366,900)	(268,700)
Operating Income/(Loss)	123,900	175,600	243,400	512,500
Interest Expense	(33,600)	(30,300)	(94,500)	(89,900)
Other Income/(Loss), Net	61,400	9,000	78,200	26,700
Net Income/(Loss) Attributable to Common Shareholders	107,500	109,500	138,400	329,600
Cash Flows Used for Investments in Plant			686,700	735,800
Assets	10,666,900		10,666,900		10,285,000
Water Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	64,200	63,500	163,500	161,500
Depreciation and Amortization	(11,100)	(11,700)	(35,000)	(34,600)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(25,500)	(25,500)	(75,400)	(73,900)
Operating Income/(Loss)	27,600	26,300	53,100	53,000
Interest Expense	(8,900)	(8,500)	(26,200)	(25,500)
Other Income/(Loss), Net	(200)	700	200	(400)
Net Income/(Loss) Attributable to Common Shareholders	17,500	$ 17,600	26,300	26,300
Cash Flows Used for Investments in Plant			79,900	$ 68,100
Assets	$ 2,311,900		$ 2,311,900		$ 2,253,000