The Connecticut Light and Power Company (CNLPM) 10-K 17 Feb 22 2021 FY Annual report Financial data

COVER PAGE

COVER PAGE - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity Registrant Name	EVERSOURCE ENERGY
Entity Incorporation, State or Country Code	MA
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	001-05324
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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 27,528,070,961
Entity Common Stock, Shares Outstanding		344,439,905
Documents Incorporated by Reference	NSTAR Electric Company and Public Service Company of New Hampshire each meet the conditions set forth in General Instruction I(1)(a) and (b) of Form 10-K, and each is therefore filing this Form 10-K with the reduced disclosure format specified in General Instruction I(2) of Form 10‑K. Eversource Energy, The Connecticut Light and Power Company, NSTAR Electric Company and Public Service Company of New Hampshire each separately file this combined Form 10-K. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants.
Entity Central Index Key	0000072741
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
The Connecticut Light and Power Company
Entity Information [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 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	000-00404
Entity Tax Identification Number	06-0303850
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		6,035,205
Entity Central Index Key	0000023426
NSTAR Electric Company
Entity Information [Line Items]
Current Fiscal Year End Date	--12-31
Entity Registrant Name	NSTAR ELECTRIC COMPANY
Entity Incorporation, State or Country Code	MA
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	001-02301
Entity Tax Identification Number	04-1278810
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		200
Entity Central Index Key	0000013372
Public Service Company of New Hampshire
Entity Information [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 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	001-06392
Entity Tax Identification Number	02-0181050
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		301
Entity Central Index Key	0000315256

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor [Line Items]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Hartford, Connecticut
The Connecticut Light and Power Company
Auditor [Line Items]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Hartford, Connecticut
NSTAR Electric Company
Auditor [Line Items]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Hartford, Connecticut
Public Service Company of New Hampshire
Auditor [Line Items]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Hartford, Connecticut

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash	$ 66,773	$ 106,599
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	1,226,069	1,195,925
Unbilled Revenues	210,879	233,025
Fuel, Materials, Supplies and REC Inventory	267,547	265,599
Regulatory Assets	1,129,093	1,076,556
Prepayments and Other Current Assets	369,759	252,439
Total Current Assets	3,270,120	3,130,143
Property, Plant and Equipment, Net	33,377,650	30,882,523
Deferred Debits and Other Assets:
Regulatory Assets	4,586,709	5,493,330
Goodwill	4,477,269	4,445,988
Investments in Unconsolidated Affiliates	1,436,293	1,107,143
Marketable Securities	460,347	456,617
Other Long-Term Assets	883,756	583,854
Total Deferred Debits and Other Assets	11,844,374	12,086,932
Total Assets	48,492,144	46,099,598
Current Liabilities:
Notes Payable	1,505,450	1,249,325
Long-Term Debt – Current Portion	1,193,097	1,053,186
Rate Reduction Bonds – Current Portion	43,210	43,210
Accounts Payable	1,672,230	1,370,647
Regulatory Liabilities	602,432	389,430
Other Current Liabilities	830,620	809,214
Total Current Liabilities	5,847,039	4,915,012
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	4,597,120	4,095,339
Regulatory Liabilities	3,866,251	3,850,781
Derivative Liabilities	235,387	294,535
Asset Retirement Obligations	500,111	499,713
Accrued Pension, SERP and PBOP	242,463	1,653,788
Other Long-Term Liabilities	971,080	948,506
Total Deferred Credits and Other Liabilities	10,412,412	11,342,662
Capitalization:
Long-Term Debt	17,023,577	15,125,876
Rate Reduction Bonds	453,702	496,912
Noncontrolling Interest - Preferred Stock of Subsidiaries	155,570	155,570
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid In	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Income	(42,275)	(76,411)
Treasury Stock	(250,878)	(277,979)
Common Shareholders' Equity	14,599,844	14,063,566
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	$ 48,492,144	$ 46,099,598

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for uncollectible accounts	$ 417,406	$ 358,851	$ 224,800

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Operating Expenses:
Purchased Power and Transmission	3,372,344	2,987,840	3,040,160
Operations and Maintenance	1,739,685	1,480,252	1,363,113
Depreciation	1,103,008	981,380	885,278
Amortization of Regulatory Assets, Net	231,965	177,679	195,380
Energy Efficiency Programs	592,775	535,760	501,369
Taxes Other Than Income Taxes	829,987	752,785	711,035
Impairment of Northern Pass Transmission	0	0	239,644
Total Operating Expenses	7,869,764	6,915,696	6,935,979
Operating Income	1,993,321	1,988,734	1,590,491
Interest Expense	582,334	538,452	533,197
Other Income, Net	161,282	108,590	132,777
Income Before Income Tax Expense	1,572,269	1,558,872	1,190,071
Income Tax Expense	344,223	346,186	273,499
Net Income	1,228,046	1,212,686	916,572
Net Income Attributable to Noncontrolling Interests	7,519	7,519	7,519
Net Income Attributable to Common Shareholders	$ 1,220,527	$ 1,205,167	$ 909,053
Basic Earnings Per Common Share (in dollars per share)	$ 3.55	$ 3.56	$ 2.83
Diluted Earnings Per Common Share (in dollars per share)	$ 3.54	$ 3.55	$ 2.81
Weighted Average Common Shares Outstanding:
Basic (in shares)	343,972,926	338,836,147	321,416,086
Diluted (in shares)	344,631,056	339,847,062	322,941,636

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Change in Funded Status of Pension, SERP and PBOP Benefit Plans	33,835	(13,290)	(7,618)
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income Attributable to Noncontrolling Interests	(7,519)	(7,519)	(7,519)
Comprehensive Income Attributable to Common Shareholders	$ 1,254,663	$ 1,193,815	$ 903,994

CONSOLIDATED STATEMENTS OF COMM

CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Adoption of New Accounting Standard	Common Shares	Capital Surplus, Paid In	Retained Earnings	Retained EarningsAdoption of New Accounting Standard	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2018			316,885,808
Beginning balance at Dec. 31, 2018	$ 11,486,817		$ 1,669,392	$ 6,241,222	$ 3,953,974		$ (60,000)	$ (317,771)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]
Net Income	$ 916,572				916,572
Dividends on Common Stock	(685,979)				(685,979)
Dividends on Preferred Stock	(7,519)				(7,519)
Issuance of Common Shares (in shares)			11,980,000
Issuance of Common Shares	868,550		$ 59,900	808,650
Long-Term Incentive Plan Activity	3,434			3,434
Issuance of Treasury Shares (in shares)			1,014,837
Issuance of Treasury Shares	69,474			50,758				18,716
Capital Stock Expense	(16,296)			(16,296)
Other Comprehensive Income/(Loss), Net of Tax	(5,059)						(5,059)
Ending balance (in shares) at Dec. 31, 2019			329,880,645
Ending balance at Dec. 31, 2019	12,629,994	$ (1,514)	$ 1,729,292	7,087,768	4,177,048	$ (1,514)	(65,059)	(299,055)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686
Dividends on Common Stock	(767,500)				(767,500)
Dividends on Preferred Stock	(7,519)				(7,519)
Capital Contributions from Eversource Parent	25,000
Issuance of Common Shares (in shares)			11,960,000
Issuance of Common Shares	949,660		$ 59,800	889,860
Long-Term Incentive Plan Activity	7,890			7,890
Issuance of Treasury Shares (in shares)			1,113,378
Issuance of Treasury Shares	71,888			50,812				21,076
Capital Stock Expense	(20,667)			(20,667)
Other Comprehensive Income/(Loss), Net of Tax	$ (11,352)						(11,352)
Ending balance (in shares) at Dec. 31, 2020	342,954,023		342,954,023
Ending balance at Dec. 31, 2020	$ 14,063,566		$ 1,789,092	8,015,663	4,613,201		(76,411)	(277,979)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,228,046				1,228,046
Dividends on Common Stock	(828,337)				(828,337)
Dividends on Preferred Stock	(7,519)				(7,519)
Long-Term Incentive Plan Activity	3,537			3,537
Issuance of Treasury Shares (in shares)			986,656
Issuance of Treasury Shares	68,364			49,913				18,451
Issuance of Treasury Shares for Acquisition of New England Service Company				29,401				8,650
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196
Ending balance at Dec. 31, 2021	$ 14,599,844		$ 1,789,092	$ 8,098,514	$ 5,005,391		$ (42,275)	$ (250,878)

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends on Common Shares (in dollars per share)	$ 2.41	$ 2.27	$ 2.14
Par value of Common Shares (in dollars per share)	$ 5	$ 5	$ 5

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	1,103,008	981,380	885,278
Deferred Income Taxes	347,056	257,154	209,812
Uncollectible Expense	60,886	53,461	63,446
Pension, SERP and PBOP (Income)/Expense, Net	(14,693)	12,888	22,000
Pension and PBOP Contributions	(182,344)	(111,524)	(121,782)
Regulatory Underrecoveries, Net	(314,211)	(516,411)	(124,870)
Reserve at CL&P related to PURA Settlement Agreement and Storm Performance Penalty	81,274	0	0
Amortization	231,965	177,679	195,380
Payments Related to CYAPC's DOE Pre-1983 Spent Nuclear Fuel Obligation	0	0	(29,000)
Proceeds from DOE Spent Nuclear Fuel Litigation	0	0	68,840
Impairment of Northern Pass Transmission	0	0	239,644
Cost of Removal Expenditures	(242,130)	(148,332)	(153,477)
Other	(64,640)	(25,957)	(42,610)
Changes in Current Assets and Liabilities:
Accounts Receivables from Subsidiaries	(135,505)	(351,843)	(98,716)
Fuel, Materials, Supplies and REC Inventory	(1,859)	(15,404)	(8,074)
Taxes Receivable/Accrued, Net	(110,621)	43,819	(16,129)
Accounts Payable	(29,201)	122,567	14,866
Other Current Assets and Liabilities, Net	5,569	(9,591)	(11,603)
Net Cash Flows Provided by Operating Activities	1,962,600	1,682,572	2,009,577
Investing Activities:
Investments in Property, Plant and Equipment	(3,175,080)	(2,942,996)	(2,911,489)
Proceeds from Sales of Marketable Securities	447,893	434,124	566,592
Purchases of Marketable Securities	(414,980)	(401,823)	(537,258)
Acquisition of Assets of Columbia Gas of Massachusetts, Net of Restricted Cash	0	(1,113,252)	0
Investments in Unconsolidated Affiliates, Net	(327,385)	(239,673)	(416,337)
Other Investing Activities	22,178	23,809	24,204
Net Cash Flows Used in Investing Activities	(3,447,374)	(4,129,275)	(3,274,288)
Financing Activities:
Issuance of Common Shares, Net of Issuance Costs	0	928,992	852,254
Cash Dividends on Common Shares	(805,439)	(744,665)	(663,239)
Cash Dividends on Preferred Stock	(7,519)	(7,519)	(7,519)
(Decrease)/Increase in Notes Payable	256,125	13,955	325,370
Repayment of Rate Reduction Bonds	(43,210)	(43,210)	(52,332)
Issuance of Long-Term Debt	3,230,000	2,760,000	1,520,000
Retirement of Long-Term Debt	(1,142,500)	(327,236)	(801,078)
Other Financing Activities	(46,625)	14,273	(1,006)
Net Cash Flows Provided by Financing Activities	1,440,832	2,594,590	1,172,450
Net (Decrease)/Increase in Cash and Restricted Cash	(43,942)	147,887	(92,261)
Cash and Restricted Cash - Beginning of Year	264,950	117,063	209,324
Cash and Restricted Cash - End of Year	221,008	264,950	117,063
Hingham Water System
Investing Activities:
Proceeds from the Sale of Generation Assets	$ 0	$ 110,536	$ 0

THE CONNECTICUT LIGHT AND POWER

THE CONNECTICUT LIGHT AND POWER COMPANY BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash	$ 66,773	$ 106,599
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	1,226,069	1,195,925
Unbilled Revenues	210,879	233,025
Fuel, Materials, Supplies and REC Inventory	267,547	265,599
Regulatory Assets	1,129,093	1,076,556
Prepayments and Other Current Assets	369,759	252,439
Total Current Assets	3,270,120	3,130,143
Property, Plant and Equipment, Net	33,377,650	30,882,523
Deferred Debits and Other Assets:
Regulatory Assets	4,586,709	5,493,330
Other Long-Term Assets	883,756	583,854
Total Deferred Debits and Other Assets	11,844,374	12,086,932
Total Assets	48,492,144	46,099,598
Current Liabilities:
Accounts Payable	1,672,230	1,370,647
Regulatory Liabilities	602,432	389,430
Other Current Liabilities	830,620	809,214
Total Current Liabilities	5,847,039	4,915,012
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	4,597,120	4,095,339
Regulatory Liabilities	3,866,251	3,850,781
Derivative Liabilities	235,387	294,535
Accrued Pension, SERP and PBOP	242,463	1,653,788
Other Long-Term Liabilities	971,080	948,506
Total Deferred Credits and Other Liabilities	10,412,412	11,342,662
Capitalization:
Long-Term Debt	17,023,577	15,125,876
Noncontrolling Interest - Preferred Stock of Subsidiaries	155,570	155,570
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid In	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Income	(42,275)	(76,411)
Common Shareholders' Equity	14,599,844	14,063,566
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	48,492,144	46,099,598
Retained Earnings
Common Shareholders' Equity:
Common Shareholders' Equity	5,005,391	4,613,201
The Connecticut Light and Power Company
Current Assets:
Cash	55,804	90,801
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	447,774	459,214
Accounts Receivable from Affiliated Companies	43,944	17,486
Unbilled Revenues	56,787	57,407
Fuel, Materials, Supplies and REC Inventory	60,264	57,924
Regulatory Assets	371,609	345,622
Prepayments and Other Current Assets	120,257	83,950
Total Current Assets	1,156,439	1,112,404
Property, Plant and Equipment, Net	10,803,543	10,234,556
Deferred Debits and Other Assets:
Regulatory Assets	1,713,161	1,866,152
Other Long-Term Assets	276,513	242,862
Total Deferred Debits and Other Assets	1,989,674	2,109,014
Total Assets	13,949,656	13,455,974
Current Liabilities:
Accounts Payable	533,454	451,240
Accounts Payable to Affiliated Companies	132,578	51,118
Obligations to Third Party Suppliers	43,183	49,967
Regulatory Liabilities	266,489	137,166
Derivative Liabilities	73,528	68,767
Other Current Liabilities	98,772	102,060
Total Current Liabilities	1,148,004	860,318
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,562,102	1,408,343
Regulatory Liabilities	1,193,259	1,204,942
Derivative Liabilities	235,387	294,535
Accrued Pension, SERP and PBOP	26,820	478,325
Other Long-Term Liabilities	153,004	133,690
Total Deferred Credits and Other Liabilities	3,170,572	3,519,835
Capitalization:
Long-Term Debt	4,215,379	3,914,835
Noncontrolling Interest - Preferred Stock of Subsidiaries	116,200	116,200
Common Shareholders' Equity:
Common Shares	60,352	60,352
Capital Surplus, Paid In	3,010,765	2,810,765
Retained Earnings	2,228,133	2,173,367
Accumulated Other Comprehensive Income	251	302
Common Shareholders' Equity	5,299,501	5,044,786
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	13,949,656	13,455,974
The Connecticut Light and Power Company | Retained Earnings
Common Shareholders' Equity:
Common Shareholders' Equity	$ 2,228,133	$ 2,173,367

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for uncollectible accounts	$ 417,406	$ 358,851	$ 224,800
The Connecticut Light and Power Company
Allowance for uncollectible accounts	$ 181,319	$ 157,447	$ 97,300

THE CONNECTICUT LIGHT AND POW_2

THE CONNECTICUT LIGHT AND POWER COMPANY STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Operating Expenses:
Purchased Power and Transmission	3,372,344	2,987,840	3,040,160
Operations and Maintenance	1,739,685	1,480,252	1,363,113
Depreciation	1,103,008	981,380	885,278
Amortization of Regulatory Assets, Net	231,965	177,679	195,380
Energy Efficiency Programs	592,775	535,760	501,369
Taxes Other Than Income Taxes	829,987	752,785	711,035
Total Operating Expenses	7,869,764	6,915,696	6,935,979
Operating Income	1,993,321	1,988,734	1,590,491
Interest Expense	582,334	538,452	533,197
Other Income, Net	161,282	108,590	132,777
Income Before Income Tax Expense	1,572,269	1,558,872	1,190,071
Income Tax Expense	344,223	346,186	273,499
Net Income	1,228,046	1,212,686	916,572
The Connecticut Light and Power Company
Operating Revenues	3,637,412	3,547,527	3,232,551
Operating Expenses:
Purchased Power and Transmission	1,392,969	1,369,196	1,188,202
Operations and Maintenance	644,175	572,897	549,167
Depreciation	338,915	320,709	301,188
Amortization of Regulatory Assets, Net	99,009	58,412	51,621
Energy Efficiency Programs	129,564	141,453	118,235
Taxes Other Than Income Taxes	363,862	344,451	342,489
Total Operating Expenses	2,968,494	2,807,118	2,550,902
Operating Income	668,918	740,409	681,649
Interest Expense	166,107	153,547	151,357
Other Income, Net	30,187	20,774	17,531
Income Before Income Tax Expense	532,998	607,636	547,823
Income Tax Expense	131,273	149,702	136,971
Net Income	$ 401,725	$ 457,934	$ 410,852

THE CONNECTICUT LIGHT AND POW_3

THE CONNECTICUT LIGHT AND POWER COMPANY STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income Attributable to Common Shareholders	1,254,663	1,193,815	903,994
The Connecticut Light and Power Company
Net Income	401,725	457,934	410,852
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	(26)	(26)	(26)
Changes in Unrealized (Losses)/Gains on Marketable Securities	(25)	12	41
Other Comprehensive Income/(Loss), Net of Tax	(51)	(14)	15
Comprehensive Income Attributable to Common Shareholders	$ 401,674	$ 457,920	$ 410,867

THE CONNECTICUT LIGHT AND POW_4

THE CONNECTICUT LIGHT AND POWER COMPANY STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Adoption of New Accounting Standard	Common Stock	Capital Surplus, Paid In	Retained Earnings	Retained EarningsAdoption of New Accounting Standard	Accumulated Other Comprehensive Loss	The Connecticut Light and Power Company	The Connecticut Light and Power CompanyAdoption of New Accounting Standard	The Connecticut Light and Power CompanyCommon Stock	The Connecticut Light and Power CompanyCapital Surplus, Paid In	The Connecticut Light and Power CompanyRetained Earnings	The Connecticut Light and Power CompanyRetained EarningsAdoption of New Accounting Standard	The Connecticut Light and Power CompanyAccumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018			316,885,808							6,035,205
Beginning balance at Dec. 31, 2018	$ 11,486,817		$ 1,669,392	$ 6,241,222	$ 3,953,974		$ (60,000)	$ 4,199,317		$ 60,352	$ 2,410,765	$ 1,727,899		$ 301
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]							Accounting Standards Update 2016-13 [Member]
Net Income	$ 916,572				916,572			$ 410,852				410,852
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(685,979)				(685,979)			(341,800)				(341,800)
Capital Contributions from Eversource Parent								125,000			125,000
Other Comprehensive Income/(Loss), Net of Tax	(5,059)						(5,059)	15						15
Ending balance (in shares) at Dec. 31, 2019			329,880,645							6,035,205
Ending balance at Dec. 31, 2019	12,629,994	$ (1,514)	$ 1,729,292	7,087,768	4,177,048	$ (1,514)	(65,059)	4,387,825	$ (900)	$ 60,352	2,535,765	1,791,392	$ (900)	316
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686			457,934				457,934
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(767,500)				(767,500)			(69,500)				(69,500)
Capital Contributions from Eversource Parent	25,000							275,000			275,000
Other Comprehensive Income/(Loss), Net of Tax	$ (11,352)						(11,352)	(14)						(14)
Ending balance (in shares) at Dec. 31, 2020	342,954,023		342,954,023							6,035,205
Ending balance at Dec. 31, 2020	$ 14,063,566		$ 1,789,092	8,015,663	4,613,201		(76,411)	5,044,786		$ 60,352	2,810,765	2,173,367		302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,228,046				1,228,046			401,725				401,725
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(828,337)				(828,337)			(341,400)				(341,400)
Capital Contributions from Eversource Parent								200,000			200,000
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136	(51)						(51)
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196							6,035,205
Ending balance at Dec. 31, 2021	$ 14,599,844		$ 1,789,092	$ 8,098,514	$ 5,005,391		$ (42,275)	$ 5,299,501		$ 60,352	$ 3,010,765	$ 2,228,133		$ 251

THE CONNECTICUT LIGHT AND POW_5

THE CONNECTICUT LIGHT AND POWER COMPANY STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	1,103,008	981,380	885,278
Deferred Income Taxes	347,056	257,154	209,812
Uncollectible Expense	60,886	53,461	63,446
Pension, SERP and PBOP (Income)/Expense, Net	(14,693)	12,888	22,000
Pension and PBOP Contributions	(182,344)	(111,524)	(121,782)
Regulatory Underrecoveries, Net	(314,211)	(516,411)	(124,870)
Reserve at CL&P related to PURA Settlement Agreement and Storm Performance Penalty	81,274	0	0
Cost of Removal Expenditures	(242,130)	(148,332)	(153,477)
Other	(64,640)	(25,957)	(42,610)
Changes in Current Assets and Liabilities:
Accounts Receivables from Subsidiaries	(135,505)	(351,843)	(98,716)
Fuel, Materials, Supplies and REC Inventory	(1,859)	(15,404)	(8,074)
Taxes Receivable/Accrued, Net	(110,621)	43,819	(16,129)
Accounts Payable	(29,201)	122,567	14,866
Other Current Assets and Liabilities, Net	5,569	(9,591)	(11,603)
Net Cash Flows Provided by Operating Activities	1,962,600	1,682,572	2,009,577
Investing Activities:
Investments in Property, Plant and Equipment	(3,175,080)	(2,942,996)	(2,911,489)
Other Investing Activities	22,178	23,809	24,204
Net Cash Flows Used in Investing Activities	(3,447,374)	(4,129,275)	(3,274,288)
Financing Activities:
Cash Dividends on Common Shares	(805,439)	(744,665)	(663,239)
Cash Dividends on Preferred Stock	(7,519)	(7,519)	(7,519)
Issuance of Long-Term Debt	3,230,000	2,760,000	1,520,000
Retirement of Long-Term Debt	(1,142,500)	(327,236)	(801,078)
Other Financing Activities	(46,625)	14,273	(1,006)
Net Cash Flows Provided by Financing Activities	1,440,832	2,594,590	1,172,450
Net (Decrease)/Increase in Cash and Restricted Cash	(43,942)	147,887	(92,261)
Cash and Restricted Cash - Beginning of Year	264,950	117,063	209,324
Cash and Restricted Cash - End of Year	221,008	264,950	117,063
The Connecticut Light and Power Company
Operating Activities:
Net Income	401,725	457,934	410,852
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	338,915	320,709	301,188
Deferred Income Taxes	123,889	144,527	54,005
Uncollectible Expense	13,495	12,882	15,948
Pension, SERP and PBOP (Income)/Expense, Net	5,295	11,372	12,761
Pension and PBOP Contributions	(98,913)	(23,200)	(24,000)
Regulatory Underrecoveries, Net	(152,775)	(279,941)	(24,653)
Reserve at CL&P related to PURA Settlement Agreement and Storm Performance Penalty	81,274	0	0
Amortization of Regulatory Assets, Net	99,009	58,412	51,621
Cost of Removal Expenditures	(95,792)	(57,343)	(60,399)
Other	(10,194)	(57,870)	(19,867)
Changes in Current Assets and Liabilities:
Accounts Receivables from Subsidiaries	(75,881)	(126,638)	(52,746)
Fuel, Materials, Supplies and REC Inventory	(2,339)	(7,225)	(6,171)
Taxes Receivable/Accrued, Net	(25,162)	(12,014)	(23,089)
Accounts Payable	24,895	(17,028)	102,344
Other Current Assets and Liabilities, Net	(14,586)	(27,504)	(11,350)
Net Cash Flows Provided by Operating Activities	612,855	397,073	726,444
Investing Activities:
Investments in Property, Plant and Equipment	(790,083)	(833,973)	(917,532)
Other Investing Activities	329	573	714
Net Cash Flows Used in Investing Activities	(789,754)	(833,400)	(916,818)
Financing Activities:
Cash Dividends on Common Shares	(341,400)	(69,500)	(341,800)
Cash Dividends on Preferred Stock	(5,559)	(5,559)	(5,559)
Increase/(Decrease) in Notes Payable to Eversource Parent	0	(63,800)	63,800
Issuance of Long-Term Debt	425,000	400,000	500,000
Retirement of Long-Term Debt	(120,500)	0	(250,000)
Capital Contributions from Eversource Parent	200,000	275,000	125,000
Other Financing Activities	(5,663)	(4,976)	12,291
Net Cash Flows Provided by Financing Activities	151,878	531,165	103,732
Net (Decrease)/Increase in Cash and Restricted Cash	(25,021)	94,838	(86,642)
Cash and Restricted Cash - Beginning of Year	99,809	4,971	91,613
Cash and Restricted Cash - End of Year	$ 74,788	$ 99,809	$ 4,971

NSTAR ELECTRIC COMPANY AND SUBS

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash	$ 66,773	$ 106,599
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	1,226,069	1,195,925
Unbilled Revenues	210,879	233,025
Fuel, Materials, Supplies and REC Inventory	267,547	265,599
Regulatory Assets	1,129,093	1,076,556
Prepayments and Other Current Assets	369,759	252,439
Total Current Assets	3,270,120	3,130,143
Property, Plant and Equipment, Net	33,377,650	30,882,523
Deferred Debits and Other Assets:
Regulatory Assets	4,586,709	5,493,330
Other Long-Term Assets	883,756	583,854
Total Deferred Debits and Other Assets	11,844,374	12,086,932
Total Assets	48,492,144	46,099,598
Current Liabilities:
Notes Payable	1,505,450	1,249,325
Long-Term Debt – Current Portion	1,193,097	1,053,186
Accounts Payable	1,672,230	1,370,647
Regulatory Liabilities	602,432	389,430
Other Current Liabilities	830,620	809,214
Total Current Liabilities	5,847,039	4,915,012
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	4,597,120	4,095,339
Regulatory Liabilities	3,866,251	3,850,781
Accrued Pension, SERP and PBOP	242,463	1,653,788
Other Long-Term Liabilities	971,080	948,506
Total Deferred Credits and Other Liabilities	10,412,412	11,342,662
Capitalization:
Long-Term Debt	17,023,577	15,125,876
Preferred Stock Not Subject to Mandatory Redemption	155,570	155,570
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid In	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Income	(42,275)	(76,411)
Common Shareholders' Equity	14,599,844	14,063,566
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	48,492,144	46,099,598
NSTAR Electric Company
Current Assets:
Cash	745	102
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	405,674	403,045
Accounts Receivable from Affiliated Companies	67,420	30,095
Unbilled Revenues	37,497	38,342
Fuel, Materials, Supplies and REC Inventory	116,712	133,894
Taxes Receivable	80,617	65,051
Regulatory Assets	443,956	399,882
Prepayments and Other Current Assets	22,397	21,833
Total Current Assets	1,175,018	1,092,244
Property, Plant and Equipment, Net	10,876,614	10,123,062
Deferred Debits and Other Assets:
Regulatory Assets	1,135,231	1,304,019
Prepaid Pension and PBOP	441,426	204,138
Other Long-Term Assets	171,657	162,836
Total Deferred Debits and Other Assets	1,748,314	1,670,993
Total Assets	13,799,946	12,886,299
Current Liabilities:
Notes Payable	162,500	195,000
Notes Payable to Eversource Parent	0	21,300
Long-Term Debt – Current Portion	400,000	250,000
Accounts Payable	490,915	383,558
Accounts Payable to Affiliated Companies	129,575	95,703
Obligations to Third Party Suppliers	116,273	98,572
Renewable Portfolio Standards Compliance Obligations	100,200	127,536
Regulatory Liabilities	228,248	164,761
Other Current Liabilities	84,303	72,118
Total Current Liabilities	1,712,014	1,408,548
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,579,508	1,459,906
Regulatory Liabilities	1,559,072	1,550,390
Accrued Pension, SERP and PBOP	2,046	172,571
Other Long-Term Liabilities	345,888	337,245
Total Deferred Credits and Other Liabilities	3,486,514	3,520,112
Capitalization:
Long-Term Debt	3,585,399	3,393,221
Preferred Stock Not Subject to Mandatory Redemption	43,000	43,000
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	2,253,942	1,993,942
Retained Earnings	2,718,576	2,527,167
Accumulated Other Comprehensive Income	501	309
Common Shareholders' Equity	4,973,019	4,521,418
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	$ 13,799,946	$ 12,886,299

NSTAR ELECTRIC COMPANY AND SU_2

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for uncollectible accounts	$ 417,406	$ 358,851	$ 224,800
NSTAR Electric Company
Allowance for uncollectible accounts	$ 97,005	$ 91,583	$ 75,400

NSTAR ELECTRIC COMPANY AND SU_3

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Operating Expenses:
Purchased Power and Transmission	3,372,344	2,987,840	3,040,160
Operations and Maintenance	1,739,685	1,480,252	1,363,113
Depreciation	1,103,008	981,380	885,278
Amortization of Regulatory Assets, Net	231,965	177,679	195,380
Energy Efficiency Programs	592,775	535,760	501,369
Taxes Other Than Income Taxes	829,987	752,785	711,035
Total Operating Expenses	7,869,764	6,915,696	6,935,979
Operating Income	1,993,321	1,988,734	1,590,491
Interest Expense	582,334	538,452	533,197
Other Income, Net	161,282	108,590	132,777
Income Before Income Tax Expense	1,572,269	1,558,872	1,190,071
Income Tax Expense	344,223	346,186	273,499
Net Income	1,228,046	1,212,686	916,572
NSTAR Electric Company
Operating Revenues	3,056,350	2,941,148	3,044,642
Operating Expenses:
Purchased Power and Transmission	932,530	879,244	1,064,289
Operations and Maintenance	563,172	534,118	468,436
Depreciation	337,451	319,468	296,500
Amortization of Regulatory Assets, Net	55,774	83,248	103,735
Energy Efficiency Programs	288,612	263,986	289,206
Taxes Other Than Income Taxes	216,703	206,764	195,586
Total Operating Expenses	2,394,242	2,286,828	2,417,752
Operating Income	662,108	654,320	626,890
Interest Expense	146,048	130,508	114,198
Other Income, Net	74,844	52,017	44,577
Income Before Income Tax Expense	590,904	575,829	557,269
Income Tax Expense	114,335	130,828	125,313
Net Income	$ 476,569	$ 445,001	$ 431,956

NSTAR ELECTRIC COMPANY AND SU_4

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Other Comprehensive Income/(Loss), Net of Tax:
Changes in Funded Status of SERP Benefit Plan	33,835	(13,290)	(7,618)
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income Attributable to Common Shareholders	1,254,663	1,193,815	903,994
NSTAR Electric Company
Net Income	476,569	445,001	431,956
Other Comprehensive Income/(Loss), Net of Tax:
Changes in Funded Status of SERP Benefit Plan	(100)	(286)	1,084
Qualified Cash Flow Hedging Instruments	298	437	437
Changes in Unrealized (Losses)/Gains on Marketable Securities	(6)	3	12
Other Comprehensive Income/(Loss), Net of Tax	192	154	1,533
Comprehensive Income Attributable to Common Shareholders	$ 476,761	$ 445,155	$ 433,489

NSTAR ELECTRIC COMPANY AND SU_5

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Adoption of New Accounting Standard	Common Stock	Capital Surplus, Paid In	Retained Earnings	Retained EarningsAdoption of New Accounting Standard	Accumulated Other Comprehensive Loss	NSTAR Electric Company	NSTAR Electric CompanyAdoption of New Accounting Standard	NSTAR Electric CompanyCommon Stock	NSTAR Electric CompanyCapital Surplus, Paid In	NSTAR Electric CompanyRetained Earnings	NSTAR Electric CompanyRetained EarningsAdoption of New Accounting Standard	NSTAR Electric CompanyAccumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018			316,885,808							200
Beginning balance at Dec. 31, 2018	$ 11,486,817		$ 1,669,392	$ 6,241,222	$ 3,953,974		$ (60,000)	$ 3,730,155		$ 0	$ 1,633,442	$ 2,098,091		$ (1,378)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	916,572				916,572			431,956				431,956
Dividends on Preferred Stock	(7,519)				(7,519)			(1,960)				(1,960)
Dividends on Common Stock	$ (685,979)				(685,979)			(181,800)				(181,800)
Capital Contributions from Eversource Parent								$ 180,000			180,000
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]							Accounting Standards Update 2016-13 [Member]
Other Comprehensive Income/(Loss), Net of Tax	$ (5,059)						(5,059)	$ 1,533						1,533
Ending balance (in shares) at Dec. 31, 2019			329,880,645							200
Ending balance at Dec. 31, 2019	12,629,994	$ (1,514)	$ 1,729,292	7,087,768	4,177,048	$ (1,514)	(65,059)	4,159,884	$ (161)	$ 0	1,813,442	2,346,287	$ (161)	155
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686			445,001				445,001
Dividends on Preferred Stock	(7,519)				(7,519)			(1,960)				(1,960)
Dividends on Common Stock	(767,500)				(767,500)			(262,000)				(262,000)
Capital Contributions from Eversource Parent	25,000							180,500			180,500
Other Comprehensive Income/(Loss), Net of Tax	$ (11,352)						(11,352)	154						154
Ending balance (in shares) at Dec. 31, 2020	342,954,023		342,954,023							200
Ending balance at Dec. 31, 2020	$ 14,063,566		$ 1,789,092	8,015,663	4,613,201		(76,411)	4,521,418		$ 0	1,993,942	2,527,167		309
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,228,046				1,228,046			476,569				476,569
Dividends on Preferred Stock	(7,519)				(7,519)			(1,960)				(1,960)
Dividends on Common Stock	(828,337)				(828,337)			(283,200)				(283,200)
Capital Contributions from Eversource Parent								260,000			260,000
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136	192						192
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196							200
Ending balance at Dec. 31, 2021	$ 14,599,844		$ 1,789,092	$ 8,098,514	$ 5,005,391		$ (42,275)	$ 4,973,019		$ 0	$ 2,253,942	$ 2,718,576		$ 501

NSTAR ELECTRIC COMPANY AND SU_6

NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	1,103,008	981,380	885,278
Deferred Income Taxes	347,056	257,154	209,812
Pension, SERP and PBOP (Income)/Expense, Net	(14,693)	12,888	22,000
Pension and PBOP Contributions	(182,344)	(111,524)	(121,782)
Regulatory Underrecoveries, Net	(314,211)	(516,411)	(124,870)
Uncollectible Expense	60,886	53,461	63,446
Cost of Removal Expenditures	(242,130)	(148,332)	(153,477)
Other	(64,640)	(25,957)	(42,610)
Changes in Current Assets and Liabilities:
Accounts Receivables from Subsidiaries	(135,505)	(351,843)	(98,716)
Fuel, Materials, Supplies and REC Inventory	(1,859)	(15,404)	(8,074)
Taxes Receivable/Accrued, Net	(110,621)	43,819	(16,129)
Accounts Payable	(29,201)	122,567	14,866
Other Current Assets and Liabilities, Net	5,569	(9,591)	(11,603)
Net Cash Flows Provided by Operating Activities	1,962,600	1,682,572	2,009,577
Investing Activities:
Investments in Property, Plant and Equipment	(3,175,080)	(2,942,996)	(2,911,489)
Other Investing Activities	22,178	23,809	24,204
Net Cash Flows Used in Investing Activities	(3,447,374)	(4,129,275)	(3,274,288)
Financing Activities:
Cash Dividends on Common Shares	(805,439)	(744,665)	(663,239)
Cash Dividends on Preferred Stock	(7,519)	(7,519)	(7,519)
(Decrease)/Increase in Notes Payable	256,125	13,955	325,370
Issuance of Long-Term Debt	3,230,000	2,760,000	1,520,000
Retirement of Long-Term Debt	(1,142,500)	(327,236)	(801,078)
Other Financing Activities	(46,625)	14,273	(1,006)
Net Cash Flows Provided by Financing Activities	1,440,832	2,594,590	1,172,450
Net (Decrease)/Increase in Cash and Restricted Cash	(43,942)	147,887	(92,261)
Cash and Restricted Cash - Beginning of Year	264,950	117,063	209,324
Cash and Restricted Cash - End of Year	221,008	264,950	117,063
NSTAR Electric Company
Operating Activities:
Net Income	476,569	445,001	431,956
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	337,451	319,468	296,500
Deferred Income Taxes	57,507	72,595	27,107
Pension, SERP and PBOP (Income)/Expense, Net	(26,120)	(18,132)	(12,399)
Pension and PBOP Contributions	(30,000)	(650)	(6,359)
Regulatory Underrecoveries, Net	(79,075)	(186,081)	(60,863)
Amortization of Regulatory Assets, Net	55,774	83,248	103,735
Uncollectible Expense	16,649	15,293	25,079
Cost of Removal Expenditures	(58,967)	(39,166)	(44,363)
Other	(32,447)	(22,888)	(33,857)
Changes in Current Assets and Liabilities:
Accounts Receivables from Subsidiaries	(45,774)	(81,571)	(11,087)
Fuel, Materials, Supplies and REC Inventory	17,182	(9,834)	(9,858)
Taxes Receivable/Accrued, Net	(16,219)	(44,045)	14,147
Accounts Payable	31,650	25,573	(22,659)
Other Current Assets and Liabilities, Net	(3,238)	(32,997)	1,194
Net Cash Flows Provided by Operating Activities	700,942	525,814	698,273
Investing Activities:
Investments in Property, Plant and Equipment	(960,949)	(907,000)	(861,391)
Other Investing Activities	91	159	86
Net Cash Flows Used in Investing Activities	(960,858)	(906,841)	(861,305)
Financing Activities:
Cash Dividends on Common Shares	(283,200)	(262,000)	(181,800)
Cash Dividends on Preferred Stock	(1,960)	(1,960)	(1,960)
(Decrease)/Increase in Notes Payable		184,500
(Decrease)/Increase in Notes Payable	(32,500)		(268,000)
(Decrease)/Increase in Notes Payable to Eversource Parent	(21,300)	(9,000)	30,300
Capital Contributions from Eversource Parent	260,000	180,500	180,000
Issuance of Long-Term Debt	600,000	400,000	400,000
Retirement of Long-Term Debt	(250,000)	(95,000)	0
Other Financing Activities	(10,355)	(4,915)	(3,855)
Net Cash Flows Provided by Financing Activities	260,685	392,125	154,685
Net (Decrease)/Increase in Cash and Restricted Cash	769	11,098	(8,347)
Cash and Restricted Cash - Beginning of Year	17,410	6,312	14,659
Cash and Restricted Cash - End of Year	$ 18,179	$ 17,410	$ 6,312

PUBLIC SERVICE COMPANY OF NEW H

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash	$ 66,773	$ 106,599
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	1,226,069	1,195,925
Unbilled Revenues	210,879	233,025
Fuel, Materials, Supplies and REC Inventory	267,547	265,599
Regulatory Assets	1,129,093	1,076,556
Prepayments and Other Current Assets	369,759	252,439
Total Current Assets	3,270,120	3,130,143
Property, Plant and Equipment, Net	33,377,650	30,882,523
Deferred Debits and Other Assets:
Regulatory Assets	4,586,709	5,493,330
Other Long-Term Assets	883,756	583,854
Total Deferred Debits and Other Assets	11,844,374	12,086,932
Total Assets	48,492,144	46,099,598
Current Liabilities:
Long-Term Debt – Current Portion	1,193,097	1,053,186
Rate Reduction Bonds – Current Portion	43,210	43,210
Accounts Payable	1,672,230	1,370,647
Regulatory Liabilities	602,432	389,430
Other Current Liabilities	830,620	809,214
Total Current Liabilities	5,847,039	4,915,012
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	4,597,120	4,095,339
Regulatory Liabilities	3,866,251	3,850,781
Accrued Pension, SERP and PBOP	242,463	1,653,788
Other Long-Term Liabilities	971,080	948,506
Total Deferred Credits and Other Liabilities	10,412,412	11,342,662
Capitalization:
Long-Term Debt	17,023,577	15,125,876
Rate Reduction Bonds	453,702	496,912
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid In	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Income	(42,275)	(76,411)
Common Shareholders' Equity	14,599,844	14,063,566
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	48,492,144	46,099,598
Public Service Company of New Hampshire
Current Assets:
Cash	15	141
Receivables, Net (net of allowance for uncollectible accounts of $181,319 and $157,447 as of December 31, 2021 and 2020, respectively)	124,232	119,899
Accounts Receivable from Affiliated Companies	17,156	10,925
Unbilled Revenues	53,937	46,041
Fuel, Materials, Supplies and REC Inventory	25,930	26,829
Regulatory Assets	107,169	115,852
Special Deposits	31,390	36,767
Prepaid Property Taxes	15,165	26,257
Prepayments and Other Current Assets	6,944	10,788
Total Current Assets	381,938	393,499
Property, Plant and Equipment, Net	3,656,462	3,374,270
Deferred Debits and Other Assets:
Regulatory Assets	679,182	873,203
Other Long-Term Assets	23,202	23,733
Total Deferred Debits and Other Assets	702,384	896,936
Total Assets	4,740,784	4,664,705
Current Liabilities:
Notes Payable to Eversource Parent	110,600	46,300
Long-Term Debt – Current Portion	0	282,000
Rate Reduction Bonds – Current Portion	43,210	43,210
Accounts Payable	166,452	132,635
Accounts Payable to Affiliated Companies	43,485	43,397
Regulatory Liabilities	120,176	58,756
Other Current Liabilities	63,005	58,487
Total Current Liabilities	546,928	664,785
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	537,978	537,627
Regulatory Liabilities	381,366	383,183
Accrued Pension, SERP and PBOP	30,184	184,715
Other Long-Term Liabilities	34,080	37,874
Total Deferred Credits and Other Liabilities	983,608	1,143,399
Capitalization:
Long-Term Debt	1,163,833	817,070
Rate Reduction Bonds	453,702	496,912
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	1,088,134	928,134
Retained Earnings	504,556	615,018
Accumulated Other Comprehensive Income	23	(613)
Common Shareholders' Equity	1,592,713	1,542,539
Commitments and Contingencies (Note 13)
Total Liabilities and Capitalization	$ 4,740,784	$ 4,664,705

PUBLIC SERVICE COMPANY OF NEW_2

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for uncollectible accounts	$ 417,406	$ 358,851	$ 224,800
Public Service Company of New Hampshire
Allowance for uncollectible accounts	$ 24,331	$ 17,157	$ 10,500

PUBLIC SERVICE COMPANY OF NEW_3

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Operating Expenses:
Purchased Power and Transmission	3,372,344	2,987,840	3,040,160
Operations and Maintenance	1,739,685	1,480,252	1,363,113
Depreciation	1,103,008	981,380	885,278
Amortization of Regulatory Assets, Net	231,965	177,679	195,380
Energy Efficiency Programs	592,775	535,760	501,369
Taxes Other Than Income Taxes	829,987	752,785	711,035
Total Operating Expenses	7,869,764	6,915,696	6,935,979
Operating Income	1,993,321	1,988,734	1,590,491
Interest Expense	582,334	538,452	533,197
Other Income, Net	161,282	108,590	132,777
Income Before Income Tax Expense	1,572,269	1,558,872	1,190,071
Income Tax Expense	344,223	346,186	273,499
Net Income	1,228,046	1,212,686	916,572
Public Service Company of New Hampshire
Operating Revenues	1,177,248	1,079,095	1,065,936
Operating Expenses:
Purchased Power and Transmission	370,271	364,067	398,449
Operations and Maintenance	237,659	219,325	210,995
Depreciation	120,065	100,372	93,737
Amortization of Regulatory Assets, Net	86,832	52,804	57,732
Energy Efficiency Programs	38,752	37,583	25,982
Taxes Other Than Income Taxes	91,465	81,611	62,574
Total Operating Expenses	945,044	855,762	849,469
Operating Income	232,204	223,333	216,467
Interest Expense	56,998	58,127	60,666
Other Income, Net	14,565	13,786	19,222
Income Before Income Tax Expense	189,771	178,992	175,023
Income Tax Expense	39,433	31,680	40,975
Net Income	$ 150,338	$ 147,312	$ 134,048

PUBLIC SERVICE COMPANY OF NEW_4

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income Attributable to Common Shareholders	1,254,663	1,193,815	903,994
Public Service Company of New Hampshire
Net Income	150,338	147,312	134,048
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	673	1,075	1,075
Changes in Unrealized (Losses)/Gains on Marketable Securities	(37)	19	69
Other Comprehensive Income/(Loss), Net of Tax	636	1,094	1,144
Comprehensive Income Attributable to Common Shareholders	$ 150,974	$ 148,406	$ 135,192

PUBLIC SERVICE COMPANY OF NEW_5

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Adoption of New Accounting Standard	Common Stock	Capital Surplus, Paid In	Retained Earnings	Retained EarningsAdoption of New Accounting Standard	Accumulated Other Comprehensive Loss	Public Service Company of New Hampshire	Public Service Company of New HampshireAdoption of New Accounting Standard	Public Service Company of New HampshireCommon Stock	Public Service Company of New HampshireCapital Surplus, Paid In	Public Service Company of New HampshireRetained Earnings	Public Service Company of New HampshireRetained EarningsAdoption of New Accounting Standard	Public Service Company of New HampshireAccumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018			316,885,808							301
Beginning balance at Dec. 31, 2018	$ 11,486,817		$ 1,669,392	$ 6,241,222	$ 3,953,974		$ (60,000)	$ 1,302,541		$ 0	$ 678,134	$ 627,258		$ (2,851)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]							Accounting Standards Update 2016-13 [Member]
Net Income	$ 916,572				916,572			$ 134,048				134,048
Dividends on Common Stock								(271,000)				(271,000)
Capital Contributions from Eversource Parent								225,000			225,000
Dividends on Common Stock	(685,979)				(685,979)
Other Comprehensive Income/(Loss), Net of Tax	(5,059)						(5,059)	1,144						1,144
Ending balance (in shares) at Dec. 31, 2019			329,880,645							301
Ending balance at Dec. 31, 2019	12,629,994	$ (1,514)	$ 1,729,292	7,087,768	4,177,048	$ (1,514)	(65,059)	1,391,733	$ (300)	$ 0	903,134	490,306	$ (300)	(1,707)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686			147,312				147,312
Capital Contributions from Eversource Parent	25,000										25,000
Dividends on Common Stock	(767,500)				(767,500)			(22,300)				(22,300)
Other Comprehensive Income/(Loss), Net of Tax	$ (11,352)						(11,352)	1,094						1,094
Ending balance (in shares) at Dec. 31, 2020	342,954,023		342,954,023							301
Ending balance at Dec. 31, 2020	$ 14,063,566		$ 1,789,092	8,015,663	4,613,201		(76,411)	1,542,539		$ 0	928,134	615,018		(613)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,228,046				1,228,046			150,338				150,338
Dividends on Common Stock								(260,800)				(260,800)
Capital Contributions from Eversource Parent								160,000			160,000
Dividends on Common Stock	(828,337)				(828,337)
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136	636						636
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196							301
Ending balance at Dec. 31, 2021	$ 14,599,844		$ 1,789,092	$ 8,098,514	$ 5,005,391		$ (42,275)	$ 1,592,713		$ 0	$ 1,088,134	$ 504,556		$ 23

PUBLIC SERVICE COMPANY OF NEW_6

PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	1,103,008	981,380	885,278
Deferred Income Taxes	347,056	257,154	209,812
Uncollectible Expense	60,886	53,461	63,446
Pension, SERP and PBOP (Income)/Expense, Net	(14,693)	12,888	22,000
Pension Contributions	(182,344)	(111,524)	(121,782)
Regulatory Over/(Underrecoveries), Net	(314,211)	(516,411)	(124,870)
Cost of Removal Expenditures	(242,130)	(148,332)	(153,477)
Other	(64,640)	(25,957)	(42,610)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(135,505)	(351,843)	(98,716)
Materials, Supplies and REC Inventory	(1,859)	(15,404)	(8,074)
Taxes Receivable/Accrued, Net	(110,621)	43,819	(16,129)
Accounts Payable	(29,201)	122,567	14,866
Other Current Assets and Liabilities, Net	5,569	(9,591)	(11,603)
Net Cash Flows Provided by Operating Activities	1,962,600	1,682,572	2,009,577
Investing Activities:
Investments in Property, Plant and Equipment	(3,175,080)	(2,942,996)	(2,911,489)
Other Investing Activities	22,178	23,809	24,204
Net Cash Flows Used in Investing Activities	(3,447,374)	(4,129,275)	(3,274,288)
Financing Activities:
Cash Dividends on Common Shares	(805,439)	(744,665)	(663,239)
Issuance of Long-Term Debt	3,230,000	2,760,000	1,520,000
Retirement of Long-Term Debt	(1,142,500)	(327,236)	(801,078)
Repayment of Rate Reduction Bonds	(43,210)	(43,210)	(52,332)
Other Financing Activities	(46,625)	14,273	(1,006)
Net Cash Flows Provided by Financing Activities	1,440,832	2,594,590	1,172,450
Net (Decrease)/Increase in Cash and Restricted Cash	(43,942)	147,887	(92,261)
Cash and Restricted Cash - Beginning of Year	264,950	117,063	209,324
Cash and Restricted Cash - End of Year	221,008	264,950	117,063
Public Service Company of New Hampshire
Operating Activities:
Net Income	150,338	147,312	134,048
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	120,065	100,372	93,737
Deferred Income Taxes	(14,530)	7,337	15,917
Uncollectible Expense	13,113	5,164	6,726
Pension, SERP and PBOP (Income)/Expense, Net	(3,296)	(1,255)	417
Pension Contributions	0	(19,500)	(15,400)
Regulatory Over/(Underrecoveries), Net	32,587	(45,830)	(26,288)
Amortization of Regulatory Assets, Net	86,832	52,804	57,732
Cost of Removal Expenditures	(30,804)	(22,063)	(21,814)
Other	(1,370)	17,221	(6,414)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(32,003)	(33,612)	(210)
Materials, Supplies and REC Inventory	899	(1,872)	1,902
Taxes Receivable/Accrued, Net	3,952	(6,942)	25,374
Accounts Payable	(3,256)	27,270	12,281
Other Current Assets and Liabilities, Net	13,555	(7,738)	(3,573)
Net Cash Flows Provided by Operating Activities	336,082	218,668	274,435
Investing Activities:
Investments in Property, Plant and Equipment	(326,379)	(342,586)	(308,993)
Other Investing Activities	562	982	1,023
Net Cash Flows Used in Investing Activities	(325,817)	(341,604)	(307,970)
Financing Activities:
Cash Dividends on Common Shares	(260,800)	(22,300)	(271,000)
Increase/(Decrease) in Notes Payable to Eversource Parent	64,300	19,300	(30,000)
Issuance of Long-Term Debt	350,000	150,000	300,000
Retirement of Long-Term Debt	(282,000)	0	(150,000)
Repayment of Rate Reduction Bonds	(43,210)	(43,210)	(52,332)
Capital Contributions from Eversource Parent	160,000	25,000	225,000
Other Financing Activities	(2,984)	(2,987)	(4,168)
Net Cash Flows Provided by Financing Activities	(14,694)	125,803	17,500
Net (Decrease)/Increase in Cash and Restricted Cash	(4,429)	2,867	(16,035)
Cash and Restricted Cash - Beginning of Year	39,555	36,688	52,723
Cash and Restricted Cash - End of Year	$ 35,126	$ 39,555	$ 36,688

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A. About Eversource, CL&P, NSTAR Electric and PSNH 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, NSTAR Gas and Eversource Gas Company of Massachusetts (EGMA) (natural gas utilities) and Aquarion (water utilities). Eversource provides energy delivery and/or water service to approximately 4.4 million electric, natural gas and water customers through ten regulated utilities in Connecticut, Massachusetts and New Hampshire. On October 9, 2020, Eversource acquired certain assets and liabilities that comprised the NiSource Inc. (NiSource) natural gas distribution business in Massachusetts, which was previously doing business as Columbia Gas of Massachusetts (CMA), pursuant to an asset purchase agreement (the Agreement) entered into on February 26, 2020 between Eversource and NiSource. The natural gas distribution assets acquired from CMA were assigned to EGMA, an indirect wholly-owned subsidiary of Eversource formed in 2020. The LNG assets acquired from CMA were assigned to Hopkinton LNG Corp. The cash purchase price was $1.1 billion, plus a working capital amount of $68.6 million, as finalized in the first quarter of 2021. Eversource's consolidated financial information includes the results of the acquisition of the assets of CMA beginning on October 9, 2020. See Note 24, "Acquisition of Assets of Columbia Gas of Massachusetts," for further information. Eversource, CL&P, NSTAR Electric and PSNH are reporting companies under the Securities Exchange Act of 1934. Eversource Energy is a public utility holding company under the Public Utility Holding Company Act of 2005. Arrangements among the regulated electric companies and other Eversource companies, outside agencies and other utilities covering interconnections, interchange of electric power and sales of utility property are subject to regulation by the FERC. Eversource's regulated companies are subject to regulation of rates, accounting and other matters by the FERC and/or applicable state regulatory commissions (the PURA for CL&P, Yankee Gas and Aquarion, the DPU for NSTAR Electric, NSTAR Gas, EGMA and Aquarion, and the NHPUC for PSNH and Aquarion). CL&P, NSTAR Electric and PSNH furnish franchised retail electric service in Connecticut, Massachusetts and New Hampshire, respectively. NSTAR Gas and EGMA are engaged in the distribution and sale of natural gas to customers within Massachusetts and Yankee Gas is engaged in the distribution and sale of natural gas to customers within Connecticut. Aquarion is engaged in the collection, treatment and distribution of water in Connecticut, Massachusetts and New Hampshire. CL&P, NSTAR Electric and PSNH's results include the operations of their respective distribution and transmission businesses. The distribution business also includes the results of NSTAR Electric's solar power facilities. Eversource Service, Eversource's service company, and several wholly-owned real estate subsidiaries of Eversource, provide support services to Eversource, including its regulated companies. B. Basis of Presentation The 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 consolidated financial statements of Eversource, NSTAR Electric and PSNH and the financial statements of CL&P are herein collectively referred to as the "financial statements." 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. Eversource consolidates the operations of CYAPC and YAEC, both of which are inactive regional nuclear power companies engaged in the long-term storage of their spent nuclear fuel. 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 holds several equity ownership interests that are not consolidated and are accounted for under the equity method. In accordance with accounting guidance on noncontrolling interests in consolidated financial statements, the Preferred Stock of CL&P and the Preferred Stock of NSTAR Electric, which are not owned by Eversource or its consolidated subsidiaries and are not subject to mandatory redemption, have been presented as noncontrolling interests in the financial statements of Eversource. The Preferred Stock of CL&P and the Preferred Stock of NSTAR Electric are considered to be temporary equity and have been classified between liabilities and permanent shareholders' equity on the balance sheets of Eversource, CL&P and NSTAR Electric due to a provision in the preferred stock agreements of both CL&P and NSTAR Electric that grant preferred stockholders the right to elect a majority of the CL&P and NSTAR Electric Boards of Directors, respectively, should certain conditions exist, such as if preferred dividends are in arrears for a specified amount of time. The Net Income reported in the statements of income and cash flows represents net income prior to apportionment to noncontrolling interests, which is represented by dividends on preferred stock of CL&P and NSTAR Electric. 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. COVID-19 has adversely affected customers, workers and the U.S. economy. We provide a critical service to our customers and have taken extensive measures to maintain its safety and reliability. We continue to address the impacts of the COVID-19 pandemic and how the related developments affect Eversource. We have not experienced significant impacts directly related to the pandemic that have materially affected our current operations, our workforce, or results of operations. The extent of the impact to us in the future will vary, and depend on the duration, scope and severity of the pandemic and the resulting impact on economic, health care and capital market conditions. The future impact will also depend on the outcome of future proceedings before our state regulatory commissions to recover our incremental costs associated with COVID-19, which include uncollectible customer receivable expenses. See Note 1F, "Summary of Significant Accounting Policies - Allowance for Uncollectible Accounts," for an evaluation of the allowance for doubtful accounts as of December 31, 2021 in light of the COVID-19 pandemic. As of December 31, 2021, we did not identify indicators or triggering events for impairments to our goodwill, long-lived assets, available-for-sale debt securities, or equity method investment carrying values. Certain reclassifications of prior year data were made in the accompanying financial statements to conform to the current year presentation. As of December 31, 2021 and 2020, Eversource's carrying amount of goodwill was $4.48 billion and $4.45 billion, respectively. Eversource performs an assessment for possible impairment of its goodwill at least annually. Eversource completed its annual goodwill impairment assessment for each of its reporting units as of October 1, 2021 and determined that no impairment exists. See Note 25, "Goodwill," for further information. C. Accounting Standards Accounting Standards Recently Adopted: On January 1, 2021, the Company adopted Accounting Standards Update (ASU) 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes , which eliminates certain exceptions to the general principles of current income tax guidance in ASC 740 and simplifies and improves consistency in application of that income tax guidance through clarifications of and amendments to ASC 740. The ASU did not have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric and PSNH. D. Impairment of Northern Pass Transmission Northern Pass was Eversource's planned 1,090 MW HVDC transmission line that would have interconnected 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 denied Northern Pass’ appeal and affirmed the NHSEC’s denial of Northern Pass’ siting application on NPT, Eversource concluded that construction of NPT was no longer probable and that there was no constructive path forward for the project. In 2019, Eversource terminated the project and permanently abandoned any further development. As a result, substantially all of the capitalized project costs, which totaled $318 million, certain of which were subject to cost reimbursement agreements, were impaired. Based on the conclusion that the construction of Northern Pass was no longer probable, Eversource recorded an impairment charge in 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 year ended December 31, 2019 and was reflected in the Electric Transmission segment. The after-tax impact of the 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. As a result of the decision to terminate the NPT project and permanently abandon any further development, Eversource does not expect any future cash expenditures associated with this project. E. Cash Cash includes cash on hand. At the end of each reporting period, any overdraft amounts are reclassified from Cash to Accounts Payable on the balance sheets. F. Allowance for Uncollectible Accounts Receivables, Net on the balance sheets primarily includes trade receivables from retail customers and customers related to wholesale transmission contracts, wholesale market sales, sales of RECs, and property rentals. Receivables, Net also includes customer receivables for the purchase of electricity from a competitive third party supplier, the current portion of customer energy efficiency loans, property damage receivables and other miscellaneous receivables. There is no material concentration of receivables. Receivables are recorded at amortized cost, net of a credit loss provision (or allowance for uncollectible accounts). Receivables are presented net of expected credit losses at estimated net realizable value by maintaining an allowance for uncollectible accounts. The current expected credit loss (CECL) model, which was implemented on January 1, 2020 (ASU 2016-13) is applied to receivables for purposes of calculating the allowance for uncollectible accounts. This model is based on expected losses and results in the recognition of estimated expected credit losses, including uncollectible amounts for both billed and unbilled revenues, over the life of the receivable at the time a receivable is recorded. The allowance for uncollectible accounts is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. Factors in determining credit loss include historical collection, write-off experience, and management's assessment of collectability from customers, including current conditions, reasonable forecasts, and expectations of future collectability and collection efforts. Management continuously assesses the collectability of receivables and adjusts estimates based on actual experience and future expectations based on economic indicators, collection efforts and other factors. Management also monitors the aging analysis of receivables to determine if there are changes in the collections of accounts receivable. Receivable balances are written off against the allowance for uncollectible accounts when the customer accounts are no longer in service and these balances are deemed to be uncollectible. As of December 31, 2021, management evaluated the adequacy of the allowance for uncollectible accounts in light of the evolving COVID-19 pandemic. This evaluation included an analysis of collection and customer payment trends, economic conditions, delinquency statistics, aging-based quantitative assessments, the impact on residential customer bills because of energy usage and change in rates, flexible payment plans and financial hardship arrearage management programs being offered to customers, and COVID-19 developments, including any potential federal governmental pandemic relief programs and the expansion of unemployment benefit initiatives, which help to mitigate the potential for increasing customer account delinquencies. Additionally, management considered past economic declines and corresponding uncollectible reserves as part of the current assessment. This evaluation has shown that our operating companies have experienced an increase in aged receivables and lower cash collections from customers because of the length of the moratorium on disconnections in Connecticut and Massachusetts, and the economic slowdown resulting from the COVID-19 pandemic. In Connecticut, the moratorium on disconnections of commercial and non-hardship residential customers ended in June 2021 and September 2021, respectively, but is still in place for hardship residential customers. In Massachusetts, the moratorium on disconnections of commercial customers and residential customers ended in September 2020 and July 2021, respectively. Disconnection activities have resumed after these moratoria have expired, which has resulted in recent improved collection experience, more customers applying for, and receiving, hardship status, and higher write-offs of aged receivable amounts. On July 7, 2021, the NHPUC issued an order to New Hampshire utilities that concluded that recovery of incremental bad debt or waived late fees related to the COVID-19 pandemic would be addressed in a future rate case to the extent those costs are relevant at that time. As a result of the order, PSNH removed its $0.6 million deferral of net incremental COVID-19 costs in 2021. In New Hampshire, the moratorium on disconnections of non-hardship residential and commercial customers ended in late 2020 and for hardship residential customers ended in May 2021 and PSNH has resumed disconnection activities, which has resulted in improved collection of outstanding customer receivable balances. Based upon the evaluation performed, for the year ended December 31, 2021, management increased the allowance for uncollectible accounts for amounts incurred as a result of COVID-19 by $24.1 million for Eversource (increase of $20.1 million for CL&P and $6.6 million at our natural gas businesses, and decrease of $1.3 million at NSTAR Electric). The COVID-19 related uncollectible amounts were deferred either as incremental regulatory costs at our Connecticut and Massachusetts utilities or deferred through existing regulatory tracking mechanisms that recover uncollectible energy supply costs, as management believes it is probable that these costs will ultimately be recovered from customers in future rates. As of December 31, 2021, the total amount incurred as a result of COVID-19 included in the allowance for uncollectible accounts was $55.3 million at Eversource ($23.9 million at CL&P, $9.0 million at NSTAR Electric, and $21.4 million at our natural gas businesses). Based on the status of our COVID-19 regulatory dockets, communications with our state regulatory commissions, and policies and practices in the jurisdictions in which we operate, we believe our state regulatory commissions in Connecticut and Massachusetts will allow us to recover our incremental costs associated with COVID-19, which include uncollectible customer receivable expenses, while balancing the impact on our customers’ bills and our operating cash flows. Management concluded that the reserve balance as of December 31, 2021 adequately reflected the collection risk and net realizable value for Eversource’s receivables. Management will continue to evaluate the adequacy of the uncollectible allowance in future reporting periods based on an ongoing assessment of accounts receivable collections, delinquency statistics, and analysis of aging-based quantitative assessments. 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, NSTAR Gas and EGMA 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. Hardship customers are protected from shut-off in certain circumstances, and historical collection experience has reflected a higher default risk as compared to the rest of the receivable population. Management uses a higher credit risk profile for this pool of trade receivables as compared to non-hardship receivables. The allowance for uncollectible hardship accounts is included in the total uncollectible allowance balance. The total allowance for uncollectible accounts is included in Receivables, Net on the balance sheets. The activity in the allowance for uncollectible accounts by portfolio segment is as follows: Eversource CL&P NSTAR Electric PSNH (Millions of Dollars) Hardship Accounts Retail (Non-Hardship), Total Allowance Hardship Accounts Retail (Non-Hardship), Total Allowance Hardship Accounts Retail (Non-Hardship), Total Allowance Total Allowance Balance as of January 1, 2020 $ 143.3 $ 81.5 $ 224.8 $ 80.1 $ 17.2 $ 97.3 $ 43.9 $ 31.5 $ 75.4 $ 10.5 ASU 2016-13 Implementation 21.6 2.2 23.8 21.3 0.9 22.2 (1.6) 0.3 (1.3) 0.3 Increase due to CMA acquisition — 24.2 24.2 — — — — — — — Uncollectible Expense (1) — 53.5 53.5 — 12.9 12.9 — 15.3 15.3 5.2 Uncollectible Costs Deferred (2) 43.1 53.9 97.0 38.2 10.8 49.0 (1.7) 26.4 24.7 7.4 Write-Offs (14.7) (63.3) (78.0) (11.9) (17.8) (29.7) (0.9) (26.3) (27.2) (6.9) Recoveries Collected 1.5 12.1 13.6 1.4 4.3 5.7 — 4.7 4.7 0.7 Balance as of December 31, 2020 $ 194.8 $ 164.1 $ 358.9 $ 129.1 $ 28.3 $ 157.4 $ 39.7 $ 51.9 $ 91.6 $ 17.2 Uncollectible Expense (1) — 60.9 60.9 — 13.5 13.5 — 16.6 16.6 13.1 Uncollectible Costs Deferred (2) 51.9 58.7 110.6 32.3 25.5 57.8 4.3 15.8 20.1 3.1 Write-Offs (22.0) (107.7) (129.7) (18.0) (36.2) (54.2) (0.7) (36.3) (37.0) (10.0) Recoveries Collected 1.4 15.3 16.7 1.2 5.6 6.8 — 5.7 5.7 0.9 Balance as of December 31, 2021 $ 226.1 $ 191.3 $ 417.4 $ 144.6 $ 36.7 $ 181.3 $ 43.3 $ 53.7 $ 97.0 $ 24.3 (1) Uncollectible expense associated with customer and other accounts receivable is included in Operations and Maintenance expense on the statements of income. For the year ended December 31, 2019, uncollectible expense included in Operations and Maintenance Expense was $63.4 million for Eversource, $15.9 million for CL&P, $25.1 million for NSTAR Electric and $6.7 million for PSNH. (2) These expected credit losses are deferred as regulatory costs on the balance sheets, as these amounts are ultimately recovered in rates. Amounts include uncollectible costs for hardship accounts and other customer receivables, including uncollectible amounts related to COVID-19 and uncollectible energy supply costs. G. Transfer of Energy Efficiency Loans CL&P transferred a portion of its energy efficiency customer loan portfolio to outside lenders in order to make additional loans to customers. CL&P remains the servicer of the loans and will transmit customer payments to the lenders, with a maximum amount outstanding under this program of $55 million. The amounts of the loans are included in Accounts Receivable, Net and Other Long-Term Assets, and are offset by Other Current Liabilities and Other Long-Term Liabilities on CL&P’s balance sheet. The current and long-term portions totaled $10.5 million and $8.3 million, respectively, as of December 31, 2021, and $12.9 million and $9.5 million, respectively, as of December 31, 2020. H. Fuel, Materials, Supplies and REC Inventory Fuel, Materials, Supplies and REC Inventory include natural gas inventory, materials and supplies purchased primarily for construction or operation and maintenance purposes, and RECs. Inventory is valued at the lower of cost or net realizable value. RECs are purchased from suppliers of renewable sources of generation and are used to meet state mandated Renewable Portfolio Standards requirements. The carrying amounts of fuel, materials and supplies, and RECs, which are included in Current Assets on the balance sheets, were as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Fuel $ 56.2 $ — $ — $ — $ 38.2 $ — $ — $ — Materials and Supplies 148.9 60.3 55.0 25.2 151.3 57.9 62.1 22.5 RECs 62.4 — 61.7 0.7 76.1 — 71.8 4.3 Total $ 267.5 $ 60.3 $ 116.7 $ 25.9 $ 265.6 $ 57.9 $ 133.9 $ 26.8 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, long-lived assets, equity method investments, and AROs, and in the valuation of the acquisition of CMA’s assets in 2020. The fair value measurement guidance was also applied in estimating the 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. The 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," Note 6, "Investments in Unconsolidated Affiliates," Note 7, "Asset Retirement Obligations," Note 11A, "Employee Benefits – Pension Benefits and Postretirement Benefits Other Than Pension," Note 15, "Fair Value of Financial Instruments," Note 24, "Acquisition of Assets of Columbia Gas of Massachusetts," and Note 25, “Goodwill,” to the financial statements. J. Derivative Accounting Many of the electric and natural gas companies' contracts for the purchase and sale of energy or energy-related products are derivatives. The accounting treatment for energy contracts entered into varies and depends on the intended use of the particular contract and on whether or not the contract is a derivative. The application of derivative accounting is complex and requires management judgment in the following respects: identification of derivatives and embedded derivatives, election and designation of a contract as normal, and determination of the fair value of derivative contracts. All of these judgments can have a significant impact on the financial statements. The judgment applied in the election of a contract as normal (and resulting accrual accounting) includes the conclusion that it is probable at the inception of the contract and throughout its term that it will result in physical delivery of the underlying product and that the quantities will be used or sold by the business in the normal course of business. If facts and circumstances change and management can no longer support this conclusion, then a contract cannot be considered normal, accrual accounting is terminated, and fair value accounting is applied prospectively. The fair value of derivative contracts is based upon the contract terms and conditions and the underlying market price or fair value per unit. When quantities are not specified in the contract, the Company determines whether the contract has a determinable quantity by using amounts referenced in default provisions and other relevant sections of the contract. The fair value of derivative assets and liabilities with the same counterparty are offset and recorded as a net derivative asset or liability on the balance sheets. Regulatory assets or regulatory liabilities are recorded to offset the fair values of derivative contracts related to energy and energy-related products, as contract settlements are recovered from, or refunded to, customers in future rates. All changes in the fair value of derivative contracts are recorded as regulatory assets or liabilities and do not impact net income. For further information regarding derivative contracts, see Note 4, "Derivative Instruments," to the financial statements. K. Operating Expenses Costs related to fuel and natural gas included in Purchased Power, Fuel and Transmission on the statements of income were as follows: For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Eversource - Natural Gas and Fuel $ 718.6 $ 464.2 $ 462.1 AFUDC represents the cost of borrowed and equity funds used to finance construction and is included in the cost of the electric, natural gas and water companies' utility plant on the balance sheet. The portion of AFUDC attributable to borrowed funds is recorded as a reduction of Interest Expense, and the AFUDC related to equity funds is recorded as Other Income, Net on the statements of income. AFUDC costs are recovered from customers over the service life of the related plant in the form of increased revenue collected as a result of higher depreciation expense. The average AFUDC rate is based on a FERC-prescribed formula using the cost of a company's short-term financings and capitalization (preferred stock, long-term debt and common equity), as appropriate. The average rate is applied to average eligible CWIP amounts to calculate AFUDC. AFUDC costs and the weighted-average AFUDC rates were as follows: Eversource For the Years Ended December 31, (Millions of Dollars, except percentages) 2021 2020 2019 Borrowed Funds $ 18.4 $ 23.7 $ 25.6 Equity Funds 37.3 42.0 45.0 Total AFUDC $ 55.7 $ 65.7 $ 70.6 Average AFUDC Rate 4.2 % 5.0 % 5.4 % For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars, CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Borrowed Funds $ 2.9 $ 9.0 $ 0.8 $ 6.6 $ 9.1 $ 2.1 $ 7.1 $ 10.4 $ 2.8 Equity Funds 7.7 20.4 1.6 13.8 21.5 4.2 13.2 19.8 3.4 Total AFUDC $ 10.6 $ 29.4 $ 2.4 $ 20.4 $ 30.6 $ 6.3 $ 20.3 $ 30.2 $ 6.2 Average AFUDC Rate 5.0 % 4.9 % 2.5 % 5.9 % 5.7 % 4.7 % 6.3 % 5.7 % 4.6 % M. Other Income, Net The components of Other Income, Net on the statements of income were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Pension, SERP and PBOP Non-Service Income Components (1) $ 84.4 $ 44.4 $ 31.3 AFUDC Equity 37.3 42.0 45.0 Equity in Earnings of Unconsolidated Affiliates (2) 14.2 14.2 42.2 Investment (Loss)/Income (0.2) 1.1 0.8 Interest Income 25.6 4.8 12.8 Other — 2.1 0.7 Total Other Income, Net $ 161.3 $ 108.6 $ 132.8 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Pension, SERP and PBOP Non-Service Income Components (1) $ 15.2 $ 40.2 $ 10.3 $ 3.8 $ 29.3 $ 7.0 $ 0.5 $ 23.5 $ 4.9 AFUDC Equity 7.7 20.4 1.6 13.8 21.5 4.2 13.2 19.8 3.4 Equity in Earnings of Unconsolidated Affiliates — 0.4 — — 0.4 — 0.1 0.7 — Investment Income/(Loss) 1.3 0.1 0.1 1.1 (0.8) 0.1 2.3 (0.4) 0.3 Interest Income 5.9 13.4 2.4 2.0 0.9 2.4 1.5 0.7 10.5 Other 0.1 0.3 0.2 0.1 0.7 0.1 (0.1) 0.3 0.1 Total Other Income, Net $ 30.2 $ 74.8 $ 14.6 $ 20.8 $ 52.0 $ 13.8 $ 17.5 $ 44.6 $ 19.2 (1) See Note 11A, "Employee Benefits – Pension Benefits and Postretirement Benefits Other Than Pension," for the components of net periodic benefit cost for the Pension, SERP and PBOP Plans. The non-service related components of pension, SERP and PBOP benefit costs, after capitalization or deferral, are presented as non-operating income and recorded in Other Income, Net on the statements of income. (2) Equity in earnings includes $2.1 million and $20.4 million of pre-tax unrealized gains for the years ended December 31, 2021 and 2019, respectively, and $2.4 million of primarily realized gains for the year ended December 31, 2020, associated with an equity method investment in a renewable energy fund. Equity in earnings of unconsolidated affiliates includes an other-than-temporary impairment of $2.8 million related to a write-off of an investment within a renewable energy fund for the year ended December 31, 2020. See Note 6, "Investments in Unconsolidated Affiliates," for further information. N. 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 Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Eversource $ 181.9 $ 170.6 $ 163.1 CL&P 158.1 149.9 141.1 Separate from above were amounts recorded as Taxes Other Than Income Taxes at CL&P related to the remittance to the State of Connecticut of energy efficiency funds collected from customers of $21.4 million in 2019. 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 paym

REGULATORY ACCOUNTING

REGULATORY ACCOUNTING	12 Months Ended
	Dec. 31, 2021
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, plus a return on investment. The application of accounting guidance for rate-regulated enterprises results in recording regulatory assets and liabilities. Regulatory assets represent the deferral of incurred costs that are probable of future recovery in customer rates. Regulatory assets are amortized as the incurred costs are recovered through customer rates. Regulatory liabilities represent either revenues received from customers to fund expected costs that have not yet been incurred or probable future refunds to customers. Management believes it is probable that each of the regulated companies will recover its respective investments in long-lived assets and the regulatory assets that have been recorded. If management were to determine that it could no longer apply the accounting guidance applicable to rate-regulated enterprises, or if management could not conclude it is probable that costs would be recovered from customers in future rates, the applicable 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 December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Benefit Costs $ 1,481.0 $ 272.4 $ 395.5 $ 118.9 $ 2,794.2 $ 632.3 $ 690.0 $ 267.6 Income Taxes, Net 790.7 470.5 112.6 17.5 747.1 458.9 110.4 15.2 Securitized Stranded Costs 478.9 — — 478.9 522.1 — — 522.1 Storm Costs, Net 1,102.7 695.6 341.3 65.8 765.6 515.1 186.4 64.1 Regulatory Tracker Mechanisms 1,050.5 333.6 376.6 85.4 850.5 246.6 332.2 95.3 Derivative Liabilities 249.2 249.2 — — 296.3 293.1 — — Goodwill-related 297.8 — 255.7 — 314.7 — 270.2 — Asset Retirement Obligations 115.0 33.6 59.8 4.1 118.4 32.1 58.6 3.9 Other Regulatory Assets 150.0 29.9 37.7 15.8 161.0 33.7 56.1 20.9 Total Regulatory Assets 5,715.8 2,084.8 1,579.2 786.4 6,569.9 2,211.8 1,703.9 989.1 Less: Current Portion 1,129.1 371.6 444.0 107.2 1,076.6 345.6 399.9 115.9 Total Long-Term Regulatory Assets $ 4,586.7 $ 1,713.2 $ 1,135.2 $ 679.2 $ 5,493.3 $ 1,866.2 $ 1,304.0 $ 873.2 Benefit Costs: Eversource's Pension, SERP and PBOP Plans are accounted for in accordance with accounting guidance on defined benefit pension and other PBOP plans. The liability (or asset) recorded by the regulated companies to recognize the funded status of their retiree benefit plans is offset by a regulatory asset (or offset by a regulatory liability in the case of a benefit plan asset) in lieu of a charge to Accumulated Other Comprehensive Income/(Loss), reflecting ultimate recovery from customers through rates. The regulatory asset (or regulatory liability) is amortized as the actuarial gains and losses and prior service cost are amortized to net periodic benefit cost for the pension and PBOP plans. All amounts are remeasured annually. Regulatory accounting is also applied to the portions of Eversource's service company costs that support the regulated companies, as these amounts are also recoverable. As these regulatory assets or regulatory liabilities do not represent a cash outlay for the regulated companies, no carrying charge is recovered from customers. See Note 11A, "Employee Benefits - Pension Benefits and Postretirement Benefits Other Than Pension," for further information on regulatory benefit plan amounts recognized and amortized during the year. CL&P, NSTAR Electric, and PSNH recover benefit costs related to their distribution and transmission operations from customers in rates as allowed by their applicable regulatory commissions. NSTAR Electric recovers qualified pension and PBOP expenses related to its distribution operations through a rate reconciling mechanism that fully tracks the change in net pension and PBOP expenses each year. Income Taxes, Net: The tax effect of temporary book-tax differences (differences between the periods in which transactions affect income in the financial statements and the periods in which they affect the determination of taxable income, including those differences relating to uncertain tax positions) is accounted for in accordance with the rate-making treatment of the applicable regulatory commissions and accounting guidance for income taxes. Differences in income taxes between the accounting guidance and the rate-making treatment of the applicable regulatory commissions are recorded as regulatory assets. As these assets are offset by deferred income tax liabilities, no carrying charge is collected. The amortization period of these assets varies depending on the nature and/or remaining life of the underlying assets and liabilities. For further information regarding income taxes, see Note 12, "Income Taxes," to the financial statements. Securitized Stranded Costs: In 2018, a subsidiary of PSNH issued $635.7 million of securitized RRBs to finance PSNH's unrecovered remaining costs associated with the divestiture of its generation assets. Securitized regulatory assets, which are not earning an equity return, are being recovered over the amortization period of the associated RRBs. The PSNH RRBs are expected to be repaid by February 1, 2033. For further information, see Note 10, "Rate Reduction Bonds and Variable Interest Entities." Storm Costs, Net: The storm cost deferrals relate to costs incurred for storm events at CL&P, NSTAR Electric and PSNH that each company expects to recover from customers. A storm must meet certain criteria to qualify for deferral and recovery with the criteria specific to each state jurisdiction and utility company. Once a storm qualifies for recovery, all qualifying expenses incurred during storm restoration efforts are deferred and recovered from customers. Costs for storms that do not meet the specific criteria are expensed as incurred. In addition to storm restoration costs, CL&P and PSNH are each allowed to recover pre-staging storm costs. Management believes all storm costs deferred were prudently incurred and meet the criteria for specific cost recovery in Connecticut, Massachusetts and New Hampshire, and that recovery from customers is probable through the applicable regulatory recovery processes. Each electric utility company either recovers a carrying charge on its deferred storm cost regulatory asset balance or the regulatory asset balance is included in rate base. In 2021 and 2020, multiple tropical and severe storms caused extensive damage to CL&P’s electric distribution systems and customer outages, along with significant pre-staging costs. These storms resulted in deferred pre-staging and storm restoration costs at CL&P of $232 million for 2021 storms and $344 million for 2020 storms, including the catastrophic impact of Tropical Storm Isaias in August 2020, among others. Management believes that all of these storm costs were prudently incurred and meet the criteria for specific cost recovery. As part of CL&P’s October 1, 2021 settlement agreement described below, it agreed to freeze its current base distribution rates (including storm costs) until no earlier than January 1, 2024. Of Eversource’s total deferred storm costs, $1.01 billion either has yet to be filed with the applicable regulatory commission or is pending regulatory approval (including $643 million at CL&P, $308 million at NSTAR Electric and $61 million at PSNH) as of December 31, 2021. CL&P Tropical Storm Isaias Costs: On August 4, 2020, Tropical Storm Isaias caused catastrophic damage to our electric distribution system, which resulted in significant numbers and durations of customer outages, primarily in Connecticut. In terms of customer outages, this storm was one of the worst in CL&P’s history. PURA will investigate the prudency of costs incurred by CL&P to restore service in response to Tropical Storm Isaias. That investigation is expected to occur either in a separate proceeding not yet initiated or as part of CL&P’s next rate review proceeding. Tropical Storm Isaias resulted in deferred storm restoration costs of approximately $234 million at CL&P and $251 million at Eversource as of December 31, 2021. Although PURA found that CL&P’s performance in its preparation for and response to Tropical Storm Isaias fell below applicable performance standards in certain instances, CL&P believes it will be able to present credible evidence in a future proceeding demonstrating there is no reasonably close causal connection between the alleged sub-standard performance and the storm costs incurred. While it is possible that some amount of storm costs may be disallowed by the PURA in a future proceeding, any such amount cannot be estimated at this time. Eversource and CL&P continue to believe that these storm restoration costs associated with Tropical Storm Isaias were prudently incurred and meet the criteria for cost recovery; and as a result, management does not expect the storm cost review by the PURA to have a material impact on the financial position or results of operations of Eversource or CL&P. NSTAR Electric Storm Threshold Filing: On December 22, 2021, the DPU approved NSTAR Electric to defer for future recovery the storm cost threshold amounts associated with six qualifying major storm events that occurred during 2020, totaling $7.2 million. The DPU approved the deferral of threshold costs that exceeded four storms (those recovered in base rates plus one additional storm) until the next rate case proceeding, at which time the DPU will determine the appropriate level of recovery of storm threshold amounts. In its January 14, 2022 distribution rate case filing, NSTAR Electric is also seeking recovery of the deferral of threshold costs for an additional seven storms in 2021. The pre-tax benefit to earnings for the deferral as a regulatory asset of threshold costs for both the 2020 and 2021 major storms was $15.6 million and was recorded in the fourth quarter of 2021. Regulatory Tracker Mechanisms: The regulated companies' approved rates are designed to recover costs incurred to provide service to customers. The regulated companies recover certain of their costs on a fully-reconciling basis through regulatory commission-approved tracking mechanisms. The differences between the costs incurred (or the rate recovery allowed) and the actual revenues are recorded as regulatory assets (for undercollections) or as regulatory liabilities (for overcollections) to be included in future customer rates each year. Carrying charges are recovered in rates on all material regulatory tracker mechanisms. The electric and natural gas distribution companies recover, on a fully reconciling basis, the costs associated with the procurement of energy supply, electric transmission related costs from FERC-approved transmission tariffs, energy efficiency programs, low income assistance programs, certain uncollectible accounts receivable for hardship customers, restructuring and stranded costs as a result of deregulation (including securitized RRB charges), certain capital tracking mechanisms for infrastructure improvements, and additionally for the Massachusetts utilities, pension and PBOP benefits, net metering for distributed generation, and solar-related programs. CL&P, NSTAR Electric, Yankee Gas, NSTAR Gas, EGMA and the Aquarion Water Company of Connecticut each have a regulatory commission approved revenue decoupling mechanism. Distribution revenues are decoupled from customer sales volumes, where applicable, which breaks the relationship between sales volumes and revenues. Each company reconciles its annual base distribution rate recovery amount to the pre-established levels of baseline distribution delivery service revenues. Any difference between the allowed level of distribution revenue and the actual amount realized during a 12-month period is adjusted through rates in the following period. CL&P Rate Adjustment Mechanisms (RAM) Filing: On July 31, 2020, PURA temporarily suspended its June 26, 2020 approval of certain delivery rate components effective July 1, 2020, and ordered CL&P to restore rates to those in effect as of June 30, 2020 in order to allow PURA time to reexamine the rates. Rates were adjusted effective August 1, 2020. On September 15, 2021, PURA issued its final decision in the 2020 RAM reconciliation filing, which required no adjustment to the GSC, BFMCC, NBFMCC, SBC, CTA, ESI and base distribution rates, but resulted in changes to the TAC and RDM rates effective October 1, 2021. As part of this decision, PURA also approved the recovery of cumulative under-recoveries associated with the NBMFCC, TAC, and RDM of $193 million effective October 1, 2021. The NBFMCC and TAC under-recoveries will be recovered over a 31-month period and the RDM under-recovery will be recovered over a 15-month period. Derivative Liabilities: Regulatory assets are recorded as an offset to derivative liabilities and relate to the fair value of contracts used to purchase energy and energy-related products that will be recovered from customers in future rates. These assets are excluded from rate base and are being recovered as the actual settlements occur over the duration of the contracts. See Note 4, "Derivative Instruments," to the financial statements for further information on these contracts. Goodwill-related: The goodwill regulatory asset originated from a 1999 transaction, and the DPU allowed its recovery in NSTAR Electric and NSTAR Gas rates. This regulatory asset is currently being amortized and recovered from customers in rates without a carrying charge over a 40-year period, and as of December 31, 2021, there were 18 years of amortization remaining. Asset Retirement Obligations: The costs associated with the depreciation of the regulated companies' ARO assets and accretion of the ARO liabilities are recorded as regulatory assets in accordance with regulatory accounting guidance. The regulated companies' ARO assets, regulatory assets, and ARO liabilities offset and are excluded from rate base. These costs are being recovered over the life of the underlying property, plant and equipment. Other Regulatory Assets: Other Regulatory Assets primarily include environmental remediation costs, losses associated with the reacquisition or redemption of long-term debt, certain uncollectible accounts receivable for hardship customers, certain merger-related costs allowed for recovery, contractual obligations associated with the spent nuclear fuel storage costs of the CYAPC, YAEC and MYAPC decommissioned nuclear power facilities, water tank painting costs, and various other items. Regulatory Costs in Long-Term Assets: Eversource's regulated companies had $252.5 million (including $114.9 million for CL&P, $85.0 million for NSTAR Electric and $3.4 million for PSNH) and $196.9 million (including $84.1 million for CL&P, $69.8 million for NSTAR Electric and $4.3 million for PSNH) of additional regulatory costs as of December 31, 2021 and 2020, 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. As of December 31, 2021 and 2020, these regulatory costs included net incremental COVID-19 related costs deferred of $39.8 million and $24.0 million at Eversource, respectively, of which, $33.0 million and $15.8 million related to non-tracked uncollectible expense and the remainder related to facilities and fleet cleaning, sanitizing costs and supplies for personal protective equipment. Net incremental COVID-19 related costs deferred at CL&P and NSTAR Electric totaled $19.0 million and $11.2 million, respectively, as of December 31, 2021 and $4.7 million and $11.9 million, respectively, as of December 31, 2020, and primarily related to deferred non-tracked uncollectible expense. Equity Return on Regulatory Assets: For rate-making purposes, the regulated companies recover the carrying costs related to their regulatory assets. For certain regulatory assets, the carrying cost recovered includes an equity return component. This equity return is not recorded on the balance sheets. There was no equity return for CL&P as of December 31, 2021 and $0.2 million as of December 31, 2020. The equity return for PSNH was $5.0 million and $5.1 million as of December 31, 2021 and 2020, respectively. These carrying costs will be recovered from customers in future rates. Regulatory Liabilities: The components of regulatory liabilities were as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH EDIT due to Tax Cuts and Jobs Act of 2017 $ 2,685.2 $ 996.1 $ 984.5 $ 359.2 $ 2,778.6 $ 1,010.7 $ 1,044.0 $ 371.5 Cost of Removal 649.6 100.1 381.0 17.2 624.8 98.4 363.6 12.9 Benefit Costs 133.5 — 107.4 — 83.6 — 72.5 — Regulatory Tracker Mechanisms 448.4 182.0 185.1 107.0 366.5 148.9 139.7 47.8 AFUDC - Transmission 81.0 43.2 37.8 — 76.8 44.6 32.2 — CL&P Settlement Agreement and Storm 81.3 81.3 — — — — — — Other Regulatory Liabilities 389.7 57.1 91.5 18.2 309.9 39.5 63.2 9.8 Total Regulatory Liabilities 4,468.7 1,459.8 1,787.3 501.6 4,240.2 1,342.1 1,715.2 442.0 Less: Current Portion 602.4 266.5 228.2 120.2 389.4 137.2 164.8 58.8 Total Long-Term Regulatory Liabilities $ 3,866.3 $ 1,193.3 $ 1,559.1 $ 381.4 $ 3,850.8 $ 1,204.9 $ 1,550.4 $ 383.2 EDIT due to Tax Cuts and Jobs Act of 2017: Pursuant to the Tax Cuts and Jobs Act of 2017, Eversource had remeasured its existing deferred federal income tax balances to reflect the decrease in the U.S. federal corporate income tax rate from 35 percent to 21 percent. The remeasurement resulted in provisional regulated excess accumulated deferred income tax (excess ADIT or EDIT) liabilities that will benefit our customers in future periods and were recognized as regulatory liabilities on the balance sheet. EDIT liabilities related to property, plant, and equipment are subject to IRS normalization rules and will be returned to customers using the same timing as the remaining useful lives of the underlying assets that gave rise to the ADIT liabilities. Eversource's regulated companies (except for the Connecticut water business) are in the process of refunding the EDIT liabilities to customers based on orders issued by applicable state and federal regulatory commissions. Cost of Removal: Eversource's regulated companies currently recover amounts in rates for future costs of removal of plant assets over the lives of the assets. The estimated cost to remove utility assets from service is recognized as a component of depreciation expense, and the cumulative amount collected from customers but not yet expended is recognized as a regulatory liability. AFUDC - Transmission: Regulatory liabilities were recorded by CL&P and NSTAR Electric for AFUDC accrued on certain reliability-related transmission projects to reflect local rate base recovery. These regulatory liabilities will be amortized over the depreciable life of the related transmission assets. CL&P Settlement Agreement and Storm Performance Penalty: On April 28, 2021, PURA issued a final decision on CL&P’s compliance with its emergency response plan that concluded CL&P failed to comply with certain storm performance standards and was imprudent in certain instances. The $28.4 million performance penalty assessed by the PURA was recorded within current regulatory liabilities on CL&P’s balance sheet and is currently being credited to customers on electric bills beginning on September 1, 2021 over a one-year period. On October 1, 2021, CL&P entered into a settlement agreement with the DEEP, Office of Consumer Counsel (OCC), Office of the Attorney General (AG) and the Connecticut Industrial Energy Consumers, resolving certain issues that arose in then-pending regulatory proceedings initiated by the PURA. PURA approved the settlement agreement on October 27, 2021. CL&P recorded a current regulatory liability of $75 million on the balance sheet associated with the provisions of the settlement agreement. Customer credits of $65 million were distributed based on customer sales over a two-month billing period from December 1, 2021 to January 31, 2022. CL&P also agreed to irrevocably set aside $10 million to provide bill payment assistance to certain existing non-hardship and hardship customers carrying arrearages, with the objective of disbursing the funds prior to April 30, 2022. The balance reflected in the table above represents the remaining reserve that has not yet been issued as customer credits or paid out of the fund as of December 31, 2021. See Note 13G, “Commitments and Contingencies - CL&P Regulatory Matters,” for further information. Other Regulatory Liabilities: Other Regulatory Liabilities primarily include the deferred portion of the non-service components of net periodic benefit expense/(income) for the Pension, SERP and PBOP Plans, EGMA’s acquired regulatory liability as a result of the 2020 DPU-approved rate settlement agreement and the CMA asset acquisition on October 9, 2020, and various other items. FERC ROE Complaints : As of December 31, 2021, Eversource has a reserve established for the second ROE complaint period in the pending FERC ROE complaint proceedings, which was recorded as a regulatory liability and is reflected within Regulatory Tracker Mechanisms in the table above. The cumulative pre-tax reserve (excluding interest) as of December 31, 2021 totaled $39.1 million for Eversource (including $21.4 million for CL&P, $14.6 million for NSTAR Electric and $3.1 million for PSNH). See Note 13E, "Commitments and Contingencies – FERC ROE Complaints," for further information on developments in the pending ROE complaint proceedings.

PROPERTY, PLANT AND EQUIPMENT A

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION Utility property, plant and equipment is recorded at original cost. Original cost includes materials, labor, construction overheads and AFUDC for regulated property. The cost of repairs and maintenance is charged to Operations and Maintenance expense as incurred. The following tables summarize property, plant and equipment by asset category: Eversource As of December 31, (Millions of Dollars) 2021 2020 Distribution - Electric $ 17,679.1 $ 16,703.2 Distribution - Natural Gas 6,694.8 6,111.2 Transmission - Electric 12,882.4 11,954.0 Distribution - Water 1,900.9 1,743.1 Solar 200.9 201.5 Utility 39,358.1 36,713.0 Other (1) 1,469.5 1,269.0 Property, Plant and Equipment, Gross 40,827.6 37,982.0 Less: Accumulated Depreciation Utility (8,885.2) (8,476.3) Other (580.1) (477.6) Total Accumulated Depreciation (9,465.3) (8,953.9) Property, Plant and Equipment, Net 31,362.3 29,028.1 Construction Work in Progress 2,015.4 1,854.4 Total Property, Plant and Equipment, Net $ 33,377.7 $ 30,882.5 As of December 31, 2021 2020 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH Distribution - Electric $ 7,117.6 $ 8,105.5 $ 2,496.2 $ 6,820.7 $ 7,544.4 $ 2,378.4 Transmission - Electric 5,859.0 5,090.5 1,934.6 5,512.0 4,701.3 1,742.4 Solar — 200.9 — — 201.5 — Property, Plant and Equipment, Gross 12,976.6 13,396.9 4,430.8 12,332.7 12,447.2 4,120.8 Less: Accumulated Depreciation (2,572.1) (3,227.3) (908.4) (2,475.4) (3,074.1) (848.9) Property, Plant and Equipment, Net 10,404.5 10,169.6 3,522.4 9,857.3 9,373.1 3,271.9 Construction Work in Progress 399.0 707.0 134.1 377.3 750.0 102.4 Total Property, Plant and Equipment, Net $ 10,803.5 $ 10,876.6 $ 3,656.5 $ 10,234.6 $ 10,123.1 $ 3,374.3 (1) These assets are primarily comprised of computer software, hardware and equipment at Eversource Service and buildings at The Rocky River Realty Company. On October 9, 2020, Eversource completed the CMA asset acquisition. EGMA’s net plant assets of $1.2 billion are reflected in the natural gas distribution asset category. On July 31, 2020, Eversource sold its water system and treatment plant that supplies water to the towns of Hingham, Hull and North Cohasset to the town of Hingham, Massachusetts. Net property, plant and equipment of $63.9 million and goodwill of $23.6 million were included in determining the gain on sale. Proceeds from the sale were $110.5 million, with a pre-tax gain of $16.0 million (after-tax gain of $3.5 million) recognized within Operations and Maintenance Expense on the statement of income for the year ended December 31, 2020. The assets and liabilities associated with the sale of the business were previously reflected in the Water Distribution segment and reporting unit. Depreciation: Depreciation of utility assets is calculated on a straight-line basis using composite rates based on the estimated remaining useful lives of the various classes of property (estimated useful life for PSNH distribution and the water utilities). The composite rates, which are subject to approval by the appropriate state regulatory agency, include a cost of removal component, which is collected from customers over the lives of the plant assets and is recognized as a regulatory liability. Depreciation rates are applied to property from the time it is placed in service. Upon retirement from service, the cost of the utility asset is charged to the accumulated provision for depreciation. The actual incurred removal costs are applied against the related regulatory liability. The depreciation rates for the various classes of utility property, plant and equipment aggregate to composite rates as follows: (Percent) 2021 2020 2019 Eversource 3.1 % 3.0 % 3.0 % CL&P 2.8 % 2.8 % 2.8 % NSTAR Electric 2.8 % 2.8 % 2.8 % PSNH 3.1 % 2.8 % 2.8 % The following table summarizes average remaining useful lives of depreciable assets: As of December 31, 2021 (Years) Eversource CL&P NSTAR Electric PSNH Distribution - Electric 33.4 35.3 33.1 29.7 Distribution - Natural Gas 39.5 — — — Transmission - Electric 40.2 36.5 45.1 40.8 Distribution - Water 38.5 — — — Solar 24.2 — 24.2 — Other (1) 11.2 — — — (1) The estimated useful life of computer software, hardware and equipment primarily ranges from 5 to 15 years and of buildings is 40 years.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	12 Months Ended
	Dec. 31, 2021
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 December 31, 2021 2020 (Millions of Dollars) Fair Value Hierarchy Commodity Supply Netting (1) Net Amount Commodity Supply Netting (1) Net Amount Current Derivative Assets: CL&P Level 3 $ 14.7 $ (1.0) $ 13.7 $ 13.7 $ (0.4) $ 13.3 Long-Term Derivative Assets: CL&P Level 3 46.9 (0.9) 46.0 58.7 (1.8) 56.9 Current Derivative Liabilities: CL&P Level 3 (73.5) — (73.5) (68.8) — (68.8) Other Level 2 — — — (3.3) 0.1 (3.2) Long-Term Derivative Liabilities: CL&P Level 3 (235.4) — (235.4) (294.5) — (294.5) (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. The business activities that result in the recognition of derivative assets also create exposure to various counterparties. As of December 31, 2021, CL&P's derivative assets were exposed to counterparty credit risk and contracted with investment grade entities. 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 both December 31, 2021 and 2020 were 675 MW. 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. As of December 31, 2020, Eversource had New York Mercantile Exchange (NYMEX) financial contracts for natural gas futures in order to reduce variability associated with the price of 8.9 million MMBtu of natural gas. These contracts were classified as Level 2 in the fair value hierarchy. NSTAR Gas terminated its financial contracts swap program in April 2021. For the years ended December 31, 2021, 2020 and 2019, there were losses of $7.1 million, $21.2 million and $20.7 million, respectively, deferred as regulatory costs, which reflect the change in fair value associated with Eversource's derivative contracts. Fair Value Measurements of Derivative Instruments 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-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-related products, and accounting requirements. The future 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 December 31, 2021 2020 CL&P Range Weighted Average (1) Period Covered Range Weighted Average (1) Period Covered Capacity Prices $2.61 $ 2.61 per kW-Month 2025 - 2026 $ 4.30 — $5.30 $ 4.63 per kW-Month 2024 - 2026 Forward Reserve $ 0.50 — $1.15 $ 0.82 per kW-Month 2022 - 2024 $ 0.54 — $0.90 $ 0.72 per kW-Month 2021 - 2024 (1) Unobservable inputs were weighted by the relative future capacity and forward reserve prices and contractual MWs over the periods covered. Exit price premiums of 5.0 percent through 9.3 percent, or a weighted average of 8.2 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. The risk premium was weighted by the relative fair value of the net derivative instruments. 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. 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 (Millions of Dollars) For the Years Ended December 31, 2021 2020 Derivatives, Net: Fair Value as of Beginning of Period $ (293.1) $ (329.2) Net Realized/Unrealized Losses Included in Regulatory Assets (8.5) (17.9) Settlements 52.4 54.0 Fair Value as of End of Period $ (249.2) $ (293.1)

MARKETABLE SECURITIES

MARKETABLE SECURITIES	12 Months Ended
	Dec. 31, 2021
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 and available-for-sale debt marketable securities are recorded at fair value, with the current portion recorded in Prepayments and Other Current Assets and the long-term portion recorded in Marketable Securities on the balance sheets. 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 December 31, 2021 and 2020 was $40.2 million and $40.9 million, respectively. For the years ended December 31, 2021 and 2020, there were unrealized gains of $4.4 million and $3.7 million recorded in Other Income, Net related to these equity securities, 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 $214.0 million and $205.1 million as of December 31, 2021 and 2020, 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 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: As of December 31, 2021 2020 Eversource (Millions of Dollars) Amortized Pre-Tax Pre-Tax Fair Value Amortized Pre-Tax Pre-Tax Fair Value Debt Securities $ 214.5 $ 5.1 $ (0.2) $ 219.4 $ 213.1 $ 11.2 $ (0.1) $ 224.2 Eversource's debt securities include CYAPC's and YAEC's marketable securities held in spent nuclear fuel trusts in the amounts of $189.9 million and $192.5 million as of December 31, 2021 and 2020, 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, excluding amounts related to credit losses or losses on securities intended to be sold, which are recorded in Other Income, Net. There have been no significant unrealized losses and no credit losses for the years ended December 31, 2021 and 2020, and no allowance for credit losses as of December 31, 2021. Factors considered in determining whether a credit loss exists include adverse conditions specifically affecting the issuer, the payment history, ratings and rating changes of the security, and the severity of the impairment. For asset-backed debt securities, underlying collateral and expected future cash flows are also evaluated. Debt securities included in Eversource's non-qualified benefit trust portfolio are investment-grade bonds with a lower default risk based on their credit quality. As of December 31, 2021, the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Fair Less than one year (1) $ 32.2 $ 32.2 One to five years 60.5 61.4 Six to ten years 35.7 36.8 Greater than ten years 86.1 89.0 Total Debt Securities $ 214.5 $ 219.4 (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 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 December 31, 2021 2020 Level 1: Mutual Funds and Equities $ 254.2 $ 246.0 Money Market Funds 31.3 41.2 Total Level 1 $ 285.5 $ 287.2 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 81.3 $ 72.9 Corporate Debt Securities 65.3 63.8 Asset-Backed Debt Securities 12.6 11.9 Municipal Bonds 12.3 24.0 Other Fixed Income Securities 16.6 10.4 Total Level 2 $ 188.1 $ 183.0 Total Marketable Securities $ 473.6 $ 470.2 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.

INVESTMENTS IN UNCONSOLIDATED A

INVESTMENTS IN UNCONSOLIDATED AFFILIATES	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
INVESTMENTS IN UNCONSOLIDATED AFFILIATES	INVESTMENTS IN UNCONSOLIDATED AFFILIATES Investments in entities that are not consolidated are included in long-term assets on the balance sheets and earnings impacts from these equity investments are included in Other Income, Net on the statements of income. Eversource's investments included the following: Investment Balance as of December 31, (Millions of Dollars) Ownership Interest 2021 2020 Offshore Wind Business - North East Offshore 50 % $ 1,213.6 $ 887.1 Natural Gas Pipeline - Algonquin Gas Transmission, LLC 15 % 121.9 125.2 Renewable Energy Investment Fund 90 % 76.5 71.6 Other various 24.3 23.2 Total Investments in Unconsolidated Affiliates $ 1,436.3 $ 1,107.1 For the years ended December 31, 2021, 2020 and 2019, Eversource had equity in earnings of unconsolidated affiliates of $14.2 million, $14.2 million, and $42.2 million, respectively. Eversource received dividends from its equity method investees of $21.6 million, $21.8 million, and $48.9 million, respectively, for the years ended December 31, 2021, 2020 and 2019. Investments in affiliates where Eversource has the ability to exercise significant influence, but not control, over an investee are initially recognized as an equity method investment at cost. Any differences between the cost of an investment and the amount of underlying equity in net assets of an investee are considered basis differences, and are determined based upon the estimated fair values of the investee's identifiable assets and liabilities. The carrying amount of Eversource’s offshore wind investments exceeded its share of underlying equity in net assets by $300.4 million and $264.1 million, respectively, as of December 31, 2021 and 2020. As of December 31, 2021, these basis differences are primarily comprised of $168.9 million of equity method goodwill that is not being amortized, intangible assets for PPAs, and capitalized interest. Offshore Wind Business: Eversource's offshore wind business includes a 50 percent ownership interest in North East Offshore, which holds PPAs and contracts for the Revolution Wind, South Fork Wind and Sunrise Wind projects, as well as offshore leases issued by BOEM. Eversource's offshore wind projects are being developed and constructed through a joint and equal partnership with Ørsted. This equity investment includes capital expenditures for the three projects, as well as capitalized costs related to future development, acquisition costs of offshore lease areas, and capitalized interest. NSTAR Electric: As of December 31, 2021 and 2020, NSTAR Electric's investments included a 14.5 percent ownership interest in two companies that transmit hydro-electricity imported from the Hydro-Quebec system in Canada of $9.0 million and $8.6 million, respectively. Impairment of Equity Method Investments: Equity method investments are assessed for impairment when conditions exist that indicate that the fair value of the investment is less than book value. If the decline in value is considered to be other-than-temporary, the investment is written down to its estimated fair value, which establishes a new cost basis in the investment. Impairment evaluations involve a significant degree of judgment and estimation, including identifying circumstances that indicate an impairment may exist and developing undiscounted future cash flows.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
	Dec. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
ASSET RETIREMENT OBLIGATIONS	ASSET RETIREMENT OBLIGATIONS Eversource, including CL&P, NSTAR Electric and PSNH, recognizes a liability for the fair value of an ARO on the obligation date if the liability's fair value can be reasonably estimated, even if it is conditional on a future event. Settlement dates and future costs are reasonably estimated when sufficient information becomes available. Management has identified various categories of AROs, primarily CYAPC's and YAEC's obligation to dispose of spent nuclear fuel and high level waste, and also certain assets containing asbestos and hazardous contamination. Management has performed fair value calculations reflecting expected probabilities for settlement scenarios. The fair value of an ARO is recorded as a long-term liability with a corresponding amount included in Property, Plant and Equipment, Net on the balance sheets. The ARO assets are depreciated, and the ARO liabilities are accreted over the estimated life of the obligation and the corresponding credits are recorded as accumulated depreciation and ARO liabilities, respectively. As the electric and natural gas companies are rate-regulated on a cost-of-service basis, these companies apply regulatory accounting guidance and both the depreciation and accretion costs associated with these companies' AROs are recorded as increases to Regulatory Assets on the balance sheets. A reconciliation of the beginning and ending carrying amounts of ARO liabilities is as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Balance as of Beginning of Year $ 499.7 $ 33.4 $ 91.8 $ 4.4 $ 489.5 $ 32.0 $ 97.5 $ 4.2 Liability Assumed Upon CMA Asset Acquisition — — — — 20.1 — — — Liabilities Incurred During the Year — — — — 2.1 — 2.1 — Liabilities Settled During the Year (23.9) (0.6) — — (21.8) (0.7) (1.0) — Accretion 29.4 2.2 4.0 0.3 28.9 2.1 4.3 0.2 Revisions in Estimated Cash Flows (5.1) — 1.7 — (19.1) — (11.1) — Balance as of End of Year $ 500.1 $ 35.0 $ 97.5 $ 4.7 $ 499.7 $ 33.4 $ 91.8 $ 4.4 Eversource's amounts include CYAPC and YAEC's AROs of $325.9 million and $330.3 million as of December 31, 2021 and 2020, respectively. The fair value of the ARO for CYAPC and YAEC includes uncertainties of the fuel off-load dates related to the DOE's timing of performance regarding its obligation to dispose of the spent nuclear fuel and high level waste and other assumptions, including discount rates. The incremental asset recorded as an offset to the ARO liability was fully depreciated since the plants have no remaining useful life. Any changes in the ARO liability are recorded with a corresponding offset to the related regulatory asset. The assets held in the CYAPC and YAEC spent nuclear fuel trusts are restricted for settling the ARO and all other nuclear fuel storage obligations. For further information on the assets held in the spent nuclear fuel trusts, see Note 5, "Marketable Securities," to the financial statements.

SHORT-TERM DEBT

SHORT-TERM DEBT	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
SHORT-TERM DEBT	SHORT-TERM DEBT Short-Term Debt - Borrowing Limits: The amount of short-term borrowings that may be incurred by CL&P and NSTAR Electric is subject to periodic approval by the FERC. Because the NHPUC has jurisdiction over PSNH's short-term debt, PSNH is not currently required to obtain FERC approval for its short-term borrowings. On December 3, 2021, the FERC granted authorization that allows CL&P to issue total short-term borrowings in an aggregate principal amount not to exceed $600 million outstanding at any one time, through December 31, 2023. On December 3, 2021, the FERC granted authorization that allows NSTAR Electric to issue total short-term borrowings in an aggregate principal amount not to exceed $655 million outstanding at any one time, through December 31, 2023. PSNH is authorized by regulation of the NHPUC to incur short-term borrowings up to 10 percent of net fixed plant plus an additional $60 million until further ordered by the NHPUC. As of December 31, 2021, PSNH's short-term debt authorization under the 10 percent of net fixed plant test plus $60 million totaled $408 million. CL&P's certificate of incorporation contains preferred stock provisions restricting the amount of unsecured debt that CL&P may incur, including limiting unsecured indebtedness with a maturity of less than 10 years to 10 percent of total capitalization. As of December 31, 2021, CL&P had $963.6 million of unsecured debt capacity available under this authorization. Yankee Gas, NSTAR Gas and EGMA are not required to obtain approval from any state or federal authority to incur short-term debt. Short-Term Debt - Commercial Paper Programs and Credit Agreements : Eversource parent has a $2.00 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, EGMA and Aquarion Water Company of Connecticut are parties to a five-year $2.00 billion revolving credit facility, which terminates on October 15, 2026. This re volving credit facility serves to backstop Eversource parent's $2.00 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 October 15, 2026. 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 Available Borrowing Capacity as of December 31, Weighted-Average Interest Rate as of December 31, (Millions of Dollars) 2021 2020 2021 2020 2021 2020 Eversource Parent Commercial Paper Program $ 1,343.0 $ 1,054.3 $ 657.0 $ 945.7 0.31 % 0.25 % NSTAR Electric Commercial Paper Program 162.5 195.0 487.5 455.0 0.14 % 0.16 % There were no borrowings outstanding on the revolving credit facilities as of December 31, 2021 or 2020. CL&P and PSNH have uncommitted line of credit agreements totaling $450 million and $300 million, respectively, which will expire on May 12, 2022. There are no borrowings outstanding on either the CL&P or PSNH uncommitted line of credit agreements as of December 31, 2021. Amounts outstanding under the commercial paper programs are included in Notes Payable and 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. Under the credit facilities described above, Eversource and its subsidiaries, including CL&P, NSTAR Electric, PSNH, NSTAR Gas, EGMA, Yankee Gas, and Aquarion Water Company of Connecticut, must comply with certain financial and non-financial covenants, including a consolidated debt to total capitalization ratio. As of December 31, 2021 and 2020, Eversource and its subsidiaries were in compliance with these covenants. If Eversource or its subsidiaries were not in compliance with these covenants, an event of default would occur requiring all outstanding borrowings by such borrower to be repaid, and additional borrowings by such borrower would not be permitted under its respective credit facility. The Company expects the future operating cash flows of Eversource, CL&P, NSTAR Electric and PSNH, along with 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.

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT Details of long-term debt outstanding are as follows: CL&P (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 7.875% 1994 Series D due 2024 $ 139.8 $ 139.8 5.750% 2004 Series B due 2034 130.0 130.0 5.625% 2005 Series B due 2035 100.0 100.0 6.350% 2006 Series A due 2036 250.0 250.0 5.750% 2007 Series B due 2037 150.0 150.0 6.375% 2007 Series D due 2037 100.0 100.0 2.500% 2013 Series A due 2023 400.0 400.0 4.300% 2014 Series A due 2044 475.0 475.0 4.150% 2015 Series A due 2045 350.0 350.0 3.200% 2017 Series A due 2027 500.0 500.0 4.000% 2018 Series A due 2048 800.0 800.0 0.750% 2020 Series A due 2025 400.0 400.0 2.050% 2021 Series A due 2031 425.0 — Total First Mortgage Bonds 4,219.8 3,794.8 Pollution Control Revenue Bonds: 4.375% Fixed Rate Tax Exempt due 2028 — 120.5 Unamortized Premiums and Discounts, Net 23.1 25.9 Unamortized Debt Issuance Costs (27.5) (26.4) CL&P Long-Term Debt $ 4,215.4 $ 3,914.8 NSTAR Electric (Millions of Dollars) As of December 31, 2021 2020 Debentures: 5.750% due 2036 $ 200.0 $ 200.0 5.500% due 2040 300.0 300.0 2.375% due 2022 400.0 400.0 4.400% due 2044 300.0 300.0 3.250% due 2025 250.0 250.0 2.700% due 2026 250.0 250.0 3.200% due 2027 700.0 700.0 3.250% due 2029 400.0 400.0 3.950% due 2030 400.0 400.0 3.100% due 2051 300.0 — 1.950% due 2031 300.0 — Total Debentures 3,800.0 3,200.0 Notes: 5.900% Senior Notes Series B due 2034 50.0 50.0 6.700% Senior Notes Series D due 2037 40.0 40.0 3.500% Senior Notes Series F due 2021 — 250.0 3.880% Senior Notes Series G due 2023 80.0 80.0 2.750% Senior Notes Series H due 2026 50.0 50.0 Total Notes 220.0 470.0 Less Amounts due Within One Year (400.0) (250.0) Unamortized Premiums and Discounts, Net (11.2) (6.8) Unamortized Debt Issuance Costs (23.4) (20.0) NSTAR Electric Long-Term Debt $ 3,585.4 $ 3,393.2 PSNH (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 5.600% Series M due 2035 $ 50.0 $ 50.0 4.050% Series Q due 2021 — 122.0 3.200% Series R due 2021 — 160.0 3.500% Series S due 2023 325.0 325.0 3.600% Series T due 2049 300.0 300.0 2.400% Series U due 2050 150.0 150.0 2.200% Series V due 2031 350.0 — Total First Mortgage Bonds 1,175.0 1,107.0 Less Amounts due Within One Year — (282.0) Unamortized Premiums and Discounts, Net (2.6) (1.5) Unamortized Debt Issuance Costs (8.6) (6.4) PSNH Long-Term Debt $ 1,163.8 $ 817.1 OTHER (Millions of Dollars) As of December 31, 2021 2020 Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 $ 765.0 $ 640.0 NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 580.0 500.0 EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051 550.0 — Aquarion - Senior Notes 4.000% due 2024 360.0 360.0 Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051 394.9 335.2 Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044 39.6 35.9 Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050 6,100.0 5,550.0 Pre-1983 Spent Nuclear Fuel Obligation (CYAPC) 11.7 11.7 Fair Value Adjustment (1) 43.8 74.7 Less Fair Value Adjustment - Current Portion (1) (17.7) (31.0) Less Amounts due in One Year (775.4) (490.2) Unamortized Premiums and Discounts, Net 43.4 46.5 Unamortized Debt Issuance Costs (36.3) (32.0) Total Other Long-Term Debt $ 8,059.0 $ 7,000.8 Total Eversource Long-Term Debt $ 17,023.6 $ 15,125.9 (1) The fair value adjustment amount is the purchase price adjustments, net of amortization, required to record long-term debt at fair value on the dates of the 2012 merger with NSTAR and the 2017 acquisition of Aquarion. Availability under Long-Term Debt Issuance Authorizations: On March 31, 2021, the DPU approved NSTAR Electric's request for authorization to issue up to $1.60 billion in long-term debt through December 31, 2023. On September 10, 2021, the DPU approved EGMA’s request for authorization to issue up to $725.0 million in long-term debt through December 31, 2023. The remaining Eversource operating companies, including CL&P and PSNH, have utilized the long-term debt authorizations in place with the respective regulatory commissions. Long-Term Debt Issuances and Repayments: The following table summarizes long-term debt issuances and repayments: (Millions of Dollars) Issuance/(Repayment) Issue Date or Repayment Date Maturity Date Use of Proceeds for Issuance/ CL&P: 2.05% Series A First Mortgage Bonds $ 425.0 June 2021 July 2031 Repaid short-term debt, paid capital expenditures and working capital 4.38% Series A PCRB (120.5) September 2021 September 2028 Paid on par call date in advance of maturity NSTAR Electric: 3.10% 2021 Debentures 300.0 May 2021 June 2051 Refinanced investments in eligible green expenditures, which were previously financed in 2019 and 2020 3.50% Series F Senior Notes (250.0) June 2021 September 2021 Paid on par call date in advance of maturity 1.95% 2021 Debentures 300.0 August 2021 August 2031 Repaid short-term debt, paid capital expenditures and working capital PSNH: 4.05% Series Q First Mortgage Bonds (122.0) March 2021 June 2021 Paid on par call date in advance of maturity 3.20% Series R First Mortgage Bonds (160.0) June 2021 September 2021 Paid on par call date in advance of maturity 2.20% Series V First Mortgage Bonds 350.0 June 2021 June 2031 Repaid short-term debt, including short-term debt used to redeem Series R First Mortgage Bonds, paid capital expenditures and working capital Other: Eversource Parent 2.50% Series I Senior Notes (450.0) February 2021 March 2021 Paid on par call date in advance of maturity Eversource Parent 2.55% Series S Senior Notes 350.0 March 2021 March 2031 Repaid short-term debt, including short-term debt used to redeem Series I Senior Notes Eversource Parent 1.40% Series U Senior Notes 300.0 August 2021 August 2026 Repaid short-term debt Eversource Parent Variable Rate Series T Senior Notes (1) 350.0 August 2021 August 2023 Repaid short-term debt Aquarion Water Company of Connecticut 3.31% Senior Notes 100.0 April 2021 April 2051 Repaid 5.50% Notes, repaid short-term debt, paid capital expenditures and working capital Aquarion Water Company of Connecticut 5.50% Notes (40.0) April 2021 April 2021 Paid at maturity Yankee Gas 1.38% Series S First Mortgage Bonds 90.0 August 2021 August 2026 (2) Yankee Gas 2.88% Series T First Mortgage Bonds 35.0 August 2021 August 2051 (2) EGMA 2.11% Series A First Mortgage Bonds 310.0 September 2021 October 2031 (2) EGMA 2.92% Series B First Mortgage Bonds 240.0 September 2021 October 2051 (2) NSTAR Gas 2.25% Series T First Mortgage Bonds 40.0 October 2021 November 2031 (2) NSTAR Gas 3.03% Series U First Mortgage Bonds 40.0 October 2021 November 2051 (2) (1) On August 13, 2021, Eversource Parent issued $350 million of floating rate Series T Senior Notes with a maturity date of August 15, 2023. The notes have a coupon rate based on Compounded SOFR plus 0.25%. The notes had an interest rate of 0.30% as of December 31, 2021. (2) The use of proceeds from these various issuances refinanced existing indebtedness, funded capital expenditures and were for general corporate purposes. The EGMA indebtedness that was refinanced included $309.4 million of long-term debt. Long-Term Debt Provisions: The utility plant of CL&P, PSNH, Yankee Gas, NSTAR Gas, EGMA and a portion of Aquarion is subject to the lien of each company's respective first mortgage bond indenture. The Eversource parent, NSTAR Electric and a portion of Aquarion debt is unsecured. Additionally, the long-term debt agreements provide that Eversource and certain of its subsidiaries must comply with certain covenants as are customarily included in such agreements, including equity requirements for NSTAR Electric, NSTAR Gas and Aquarion. Under the equity requirements, NSTAR Electric's and Aquarion's senior notes must maintain a certain consolidated indebtedness to capitalization ratio as of the end of any fiscal quarter and NSTAR Gas' outstanding long-term debt must not exceed equity. Certain secured and unsecured long-term debt securities are callable at redemption price or are subject to make-whole provisions. No long-term debt defaults have occurred as of December 31, 2021. CYAPC's Pre-1983 Spent Nuclear Fuel Obligation: Under the Nuclear Waste Policy Act of 1982, the DOE is responsible for the selection and development of repositories for, and the disposal of, spent nuclear fuel and high-level radioactive waste. CYAPC is obligated to pay the DOE for the costs to dispose of spent nuclear fuel and high-level radioactive waste generated prior to April 7, 1983 (pre-1983 Spent Nuclear Fuel). CYAPC has partially paid this obligation and recorded an accrual for its remaining liability to the DOE. This liability accrues interest costs at the 3-month Treasury bill yield rate. For nuclear fuel used to generate electricity prior to April 7, 1983, payment may be made any time prior to the first delivery of spent fuel to the DOE. As of both December 31, 2021 and 2020, as a result of consolidating CYAPC, Eversource has consolidated $11.7 million, in pre-1983 spent nuclear fuel obligations to the DOE. The obligation includes accumulated interest costs of $8.7 million as of both December 31, 2021 and 2020. CYAPC maintains a trust to fund amounts due to the DOE for the disposal of pre-1983 spent nuclear fuel. For further information, see Note 5, "Marketable Securities," to the financial statements. Fees for disposal of nuclear fuel burned on or after April 7, 1983 were billed to member companies and paid to the DOE. Long-Term Debt Maturities: Long-term debt maturities on debt outstanding for the years 2022 through 2026 and thereafter are shown below. These amounts exclude PSNH rate reduction bonds, CYAPC pre-1983 spent nuclear fuel obligation, net unamortized premiums, discounts and debt issuance costs, and other fair value adjustments as of December 31, 2021: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2022 $ 1,175.4 $ — $ 400.0 $ — 2023 2,008.4 400.0 80.0 325.0 2024 1,050.1 139.8 — — 2025 1,400.2 400.0 250.0 — 2026 940.2 — 300.0 — Thereafter 11,630.0 3,280.0 2,990.0 850.0 Total $ 18,204.3 $ 4,219.8 $ 4,020.0 $ 1,175.0

RATE REDUCTION BONDS AND VARIAB

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES	12 Months Ended
	Dec. 31, 2021
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: In May 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 are paid semi-annually, beginning on February 1, 2019. The RRBs were issued pursuant to a finance order issued by the NHPUC in January 2018 to recover remaining costs resulting from the divestiture of PSNH’s generation assets. The proceeds were used by PSNH Funding to purchase PSNH’s stranded cost asset-recovery property, including its vested property right to bill, collect and adjust a non-bypassable stranded cost recovery charge from PSNH’s retail customers. The collections are used to pay principal, interest and other costs in connection with the RRBs. The RRBs are secured by the stranded cost asset-recovery property. Cash collections from the stranded cost recovery charges and funds on deposit in trust accounts are the sole source of funds to satisfy the debt obligation. PSNH is not the owner of the RRBs, and PSNH Funding’s assets and revenues are not available to pay PSNH’s creditors. The RRBs are non-recourse senior secured obligations of PSNH Funding and are not insured or guaranteed by PSNH or Eversource Energy. PSNH Funding was formed solely to issue RRBs to finance PSNH's unrecovered remaining costs associated with the divestiture of its 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) As of December 31, PSNH Balance Sheets: 2021 2020 Restricted Cash - Current Portion (included in Current Assets) $ 31.1 $ 36.8 Restricted Cash - Long-Term Portion (included in Other Long-Term Assets) 3.2 2.1 Securitized Stranded Cost (included in Regulatory Assets) 478.9 522.1 Other Regulatory Liabilities (included in Regulatory Liabilities) 5.4 9.1 Accrued Interest (included in Other Current Liabilities) 7.5 8.0 Rate Reduction Bonds - Current Portion 43.2 43.2 Rate Reduction Bonds - Long-Term Portion 453.7 496.9 (Millions of Dollars) PSNH Income Statements: For the Years Ended December 31, 2021 2020 2019 Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net) $ 43.2 $ 43.2 $ 43.0 Interest Expense on RRB Principal (included in Interest Expense) 18.4 19.7 21.1 Estimated principal and interest payments on RRBs as of December 31, 2021, is summarized annually through 2026 and thereafter as follows: (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Eversource $ 43.2 $ 43.2 $ 43.2 $ 43.2 $ 43.2 $ 280.9 $ 496.9 Variable Interest Entities - Other: The Company's variable interests outside of the consolidated group include contracts that are required by regulation and provide for regulatory recovery of contract costs and benefits through customer rates. Eversource, CL&P and NSTAR Electric hold variable interests in VIEs through agreements with certain entities that own single renewable energy or peaking generation power plants, with other independent power producers and with transmission businesses. Eversource, CL&P and NSTAR Electric do not control the activities that are economically significant to these VIEs or provide financial or other support to these VIEs. Therefore, Eversource, CL&P and NSTAR Electric do not consolidate these VIEs.

EMPLOYEE BENEFITS

EMPLOYEE BENEFITS	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
EMPLOYEE BENEFITS	EMPLOYEE BENEFITS A. Pension Benefits and Postretirement Benefits Other Than Pension Eversource provides defined benefit retirement plans (Pension Plans) that cover eligible employees and are subject to the provisions of ERISA, as amended by the Pension Protection Act of 2006. Eversource's policy is to annually fund the Pension Plans in an amount at least equal to an amount that will satisfy all federal funding requirements. 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. The benefits provided under the PBOP Plans are not vested, and the Company has the right to modify any benefit provision subject to applicable laws at that time. Eversource annually funds postretirement costs through tax deductible contributions to external trusts. The Pension, SERP and PBOP Plans cover eligible employees, including, among others, employees of the regulated companies. Because the regulated companies recover retiree benefit costs from customers through rates, regulatory assets are recorded in lieu of recording an adjustment to Accumulated Other Comprehensive Income/(Loss) as an offset to the funded status of the Pension, SERP and PBOP Plans. Regulatory accounting is also applied to the portions of the Eversource Service retiree benefit costs that support the regulated companies, as these costs are also recovered from customers. Adjustments to the Pension, SERP and PBOP Plans' funded status for the unregulated companies are recorded on an after-tax basis to Accumulated Other Comprehensive Income/(Loss). For further information, see Note 2, "Regulatory Accounting," and Note 16, "Accumulated Other Comprehensive Income/(Loss)," to the financial statements. Funded Status: The Pension, SERP and PBOP Plans are accounted for under the multiple-employer approach, with each operating company's balance sheet reflecting its share of the funded status of the plans. Although Eversource maintains marketable securities in a benefit trust, the SERP Plans do not contain any assets. For further information, see Note 5, "Marketable Securities," to the financial statements. The following tables provide information on the plan benefit obligations, fair values of plan assets, and funded status: Pension and SERP As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Change in Benefit Obligation: Benefit Obligation as of Beginning of Year $ (7,045.3) $ (1,477.3) $ (1,517.9) $ (748.7) $ (6,321.7) $ (1,331.3) $ (1,397.3) $ (692.6) Service Cost (85.8) (23.0) (15.8) (8.9) (76.2) (21.8) (15.4) (8.2) Interest Cost (130.0) (27.3) (26.8) (14.5) (177.8) (37.3) (38.6) (19.4) Actuarial Gain/(Loss) 177.1 127.8 20.8 14.7 (658.2) (152.3) (139.5) (62.1) Benefits Paid - Pension 309.5 64.6 68.7 34.7 279.3 63.6 59.4 33.5 Benefits Paid - Lump Sum 34.7 — 15.6 — 23.4 — 13.1 — Benefits Paid - SERP 10.1 0.3 0.2 0.4 7.3 0.3 0.2 0.4 Employee Transfers — 4.0 6.8 1.3 — 1.5 0.2 (0.3) Increase due to acquisition of CMA — — — — (121.4) — — — Benefit Obligation as of End of Year $ (6,729.7) $ (1,330.9) $ (1,448.4) $ (721.0) $ (7,045.3) $ (1,477.3) $ (1,517.9) $ (748.7) Change in Pension Plan Assets: Fair Value of Pension Plan Assets as of $ 5,409.2 $ 1,043.1 $ 1,345.1 $ 593.7 $ 4,968.6 $ 986.2 $ 1,288.8 $ 551.6 Employer Contributions 180.0 98.9 30.0 — 109.6 23.2 0.7 19.5 Actual Return on Pension Plan Assets 1,250.5 250.4 312.0 136.9 512.3 98.8 128.3 55.8 Benefits Paid - Pension (309.5) (64.6) (68.7) (34.7) (279.3) (63.6) (59.4) (33.5) Benefits Paid - Lump Sum (34.7) — (15.6) — (23.4) — (13.1) — Employee Transfers — (4.0) (6.8) (1.3) — (1.5) (0.2) 0.3 Increase due to acquisition of CMA — — — — 121.4 — — — Fair Value of Pension Plan Assets as of End of Year $ 6,495.5 $ 1,323.8 $ 1,596.0 $ 694.6 $ 5,409.2 $ 1,043.1 $ 1,345.1 $ 593.7 Funded Status as of December 31st $ (234.2) $ (7.1) $ 147.6 $ (26.4) $ (1,636.1) $ (434.2) $ (172.8) $ (155.0) For the year ended December 31, 2021, the decrease in Eversource's pension liability was primarily attributable to an increase in the return on pension assets. While all pension asset classes performed well, the driver of the increase came from higher valuations of Eversource’s private equity investments. Actuarial Gains and Losses: For the year ended December 31, 2021, the decrease in the benefit obligation due to actuarial gains was primarily attributable to an increase in the discount rate, which resulted in a decrease to Eversource's pension liability of $286.8 million. The decrease in the benefit obligation was partially offset by changes in the mortality assumption. For the year ended December 31, 2020, the increase in the benefit obligation due to actuarial losses was primarily attributable to a decrease in the discount rate, which resulted in an increase to Eversource's pension liability of $603.0 million, which was partially offset by changes in the mortality assumption. The pension and SERP Plans' funded status includes the current portion of the SERP liability totaling $9.7 million and $6.8 million as of December 31, 2021 and 2020, respectively, which is included in Other Current Liabilities on the balance sheets. As of December 31, 2021 and 2020, the accumulated benefit obligation for the Pension and SERP Plans is as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2021 $ 6,337.3 $ 1,241.1 $ 1,376.1 $ 670.3 2020 6,669.4 1,356.4 1,449.4 707.2 PBOP As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Change in Benefit Obligation: Benefit Obligation as of Beginning of Year $ (993.9) $ (178.6) $ (260.5) $ (109.5) $ (899.0) $ (172.7) $ (258.3) $ (93.0) Service Cost (13.5) (2.3) (2.4) (1.2) (10.2) (1.7) (2.1) (0.9) Interest Cost (17.4) (3.2) (4.4) (1.8) (24.6) (4.4) (6.6) (2.8) Actuarial Gain/(Loss) 81.4 5.8 11.5 14.6 (82.8) (8.6) (7.4) (19.0) Benefits Paid 51.7 10.9 16.3 5.6 50.2 10.1 14.9 6.1 Employee Transfers — 1.9 1.1 — — (1.3) (1.0) 0.1 Impact of Acquisition of CMA 7.4 — — — (27.5) — — — Benefit Obligation as of End of Year $ (884.3) $ (165.5) $ (238.4) $ (92.3) $ (993.9) $ (178.6) $ (260.5) $ (109.5) Change in Plan Assets: Fair Value of Plan Assets as of Beginning of Year $ 1,004.1 $ 134.1 $ 464.6 $ 79.4 $ 935.9 $ 126.3 $ 424.4 $ 76.0 Actual Return on Plan Assets 183.2 24.1 84.2 14.2 116.5 15.7 53.3 9.3 Employer Contributions 2.3 — — — 1.9 — — — Benefits Paid (51.3) (10.9) (16.3) (5.6) (50.2) (10.1) (14.9) (6.1) Employee Transfers — (1.6) (2.5) — — 2.2 1.8 0.2 Fair Value of Plan Assets as of End of Year $ 1,138.3 $ 145.7 $ 530.0 $ 88.0 $ 1,004.1 $ 134.1 $ 464.6 $ 79.4 Funded Status as of December 31st $ 254.0 $ (19.8) $ 291.6 $ (4.3) $ 10.2 $ (44.5) $ 204.1 $ (30.1) The Eversource PBOP funded status includes prepaid assets of $272 million and $34.7 million recorded in Other Long-Term Assets and liabilities of $18.0 million and $24.5 million included in Accrued Pension, SERP and PBOP on the balance sheets as of December 31, 2021 and 2020, respectively. Actuarial Gains and Losses: For the year ended December 31, 2021, the decrease in the benefit obligation due to actuarial gains was primarily attributable to an increase in the discount rate, which resulted in a decrease to the Eversource PBOP liability of $29.8 million, and by changes in our retirement assumptions. For the year ended December 31, 2020, the increase in the benefit obligation due to actuarial losses was primarily attributable to a decrease in the discount rate, which resulted in an increase to the Eversource PBOP liability of $68.3 million, and by changes in our retirement assumptions. The following actuarial assumptions were used in calculating the Pension, SERP and PBOP Plans' year end funded status: Pension and SERP PBOP As of December 31, As of December 31, 2021 2020 2021 2020 Discount Rate 2.8% — 3.0% 2.4% — 2.7% 2.91% — 2.92% 2.5% — 2.6% Compensation/Progression Rate 3.5% — 4.0% 3.5% — 4.0% N/A For the Eversource Service PBOP Plan, the health care cost trend rate is not applicable. For the Aquarion PBOP Plan, the health care cost trend rate for pre-65 retirees is 6.5 percent, with an ultimate rate of 5 percent in 2028, and for post-65 retirees, the health care trend rate and ultimate rate is 3.5 percent. Expense: Eversource charges net periodic benefit plan expense/(income) for the Pension, SERP and PBOP Plans to its subsidiaries based on the actual participant demographic data for each subsidiary's participants. The actual investment return in the trust is allocated to each of the subsidiaries annually in proportion to the investment return expected to be earned during the year. The Company utilizes the spot rate methodology to estimate the discount rate for the service and interest cost components of benefit expense, which provides a relatively precise measurement by matching projected cash flows to the corresponding spot rates on the yield curve. The components of net periodic benefit plan expense/(income) for the Pension, SERP and PBOP Plans, prior to amounts capitalized as Property, Plant and Equipment or deferred as regulatory assets/(liabilities) for future recovery or refund, are shown below. The service cost component of net periodic benefit plan expense/(income), less the capitalized portion, is included in Operations and Maintenance expense on the statements of income. The remaining components of net periodic benefit plan 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 intercompany allocations of net periodic benefit plan expense/(income), as these amounts are cash settled on a short-term basis. Pension and SERP PBOP For the Year Ended December 31, 2021 For the Year Ended December 31, 2021 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 85.8 $ 23.0 $ 15.8 $ 8.9 $ 13.5 $ 2.3 $ 2.4 $ 1.2 Interest Cost 130.0 27.3 26.8 14.5 17.4 3.2 4.4 1.8 Expected Return on Plan Assets (437.5) (86.8) (108.1) (47.5) (79.1) (10.3) (36.9) (6.1) Actuarial Loss 243.9 45.5 61.6 20.7 8.9 1.8 2.4 0.7 Prior Service Cost/(Credit) 1.4 — 0.3 — (21.2) 1.1 (17.0) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 23.6 $ 9.0 $ (3.6) $ (3.4) $ (60.5) $ (1.9) $ (44.7) $ (2.0) Intercompany Expense/(Income) Allocations N/A $ 8.0 $ 8.8 $ 2.7 N/A $ (1.6) $ (1.9) $ (0.6) Pension and SERP PBOP For the Year Ended December 31, 2020 For the Year Ended December 31, 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 76.2 $ 21.8 $ 15.4 $ 8.2 $ 10.2 $ 1.7 $ 2.1 $ 0.9 Interest Cost 177.8 37.3 38.6 19.4 24.6 4.4 6.6 2.8 Expected Return on Plan Assets (400.3) (79.2) (103.0) (44.7) (73.6) (9.9) (34.0) (5.7) Actuarial Loss 202.0 39.2 55.2 15.6 8.4 1.1 2.5 0.8 Prior Service Cost/(Credit) 1.2 — 0.3 — (21.2) 1.1 (17.0) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 56.9 $ 19.1 $ 6.5 $ (1.5) $ (51.6) $ (1.6) $ (39.8) $ (0.8) Intercompany Expense/(Income) Allocations N/A $ 9.1 $ 8.9 $ 2.9 N/A $ (1.1) $ (1.4) $ (0.5) Pension and SERP PBOP For the Year Ended December 31, 2019 For the Year Ended December 31, 2019 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 67.7 $ 18.0 $ 14.6 $ 7.1 $ 7.8 $ 1.4 $ 1.7 $ 0.7 Interest Cost 219.0 45.7 49.0 24.0 32.7 6.3 9.5 3.4 Expected Return on Plan Assets (367.1) (73.2) (97.1) (40.7) (66.8) (9.2) (30.2) (5.4) Actuarial Loss 143.2 26.9 44.7 10.6 8.3 1.3 3.3 0.3 Prior Service Cost/(Credit) 0.9 — 0.3 — (23.5) 1.1 (16.9) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 63.7 $ 17.4 $ 11.5 $ 1.0 $ (41.5) $ 0.9 $ (32.6) $ (0.6) Intercompany Expense/(Income) Allocations N/A $ 8.5 $ 8.0 $ 2.3 N/A $ (0.9) $ (1.2) $ (0.4) The following actuarial assumptions were used to calculate Pension, SERP and PBOP expense amounts: Pension and SERP PBOP For the Years Ended December 31, For the Years Ended December 31, 2021 2020 2019 2021 2020 2019 Discount Rate 1.5% — 3.0% 2.6% — 3.5% 2.7% — 3.6% 1.8% — 3.1% 2.7% — 3.6% 3.9% — 4.6% Expected Long-Term Rate of Return 8.25% 8.25% 8.25% 8.25% 8.25% 8.25% Compensation/Progression Rate 3.5% — 4.0% 3.5% — 4.0% 3.5% — 4.0% N/A N/A N/A For the Aquarion Pension and PBOP Plans, the expected long-term rate of return was 7 percent for the years ended December 31, 2021 and 2020. For the Aquarion PBOP Plan, the health care cost trend rate was a range of 3.5 percent to 6.2 percent for the year ended December 31, 2021 and 3.5 percent to 6.5 percent for the year ended December 31, 2020. The following is a summary of the changes in plan assets and benefit obligations recognized in Regulatory Assets and Other Comprehensive Income (OCI) as well as amounts in Regulatory Assets and OCI that were reclassified as net periodic benefit expense during the years presented: Pension and SERP PBOP Regulatory Assets OCI Regulatory Assets OCI For the Years Ended December 31, For the Years Ended December 31, (Millions of Dollars) 2021 2020 (1) 2021 2020 2021 2020 (1) 2021 2020 Actuarial (Gains)/Losses Arising During the Year $ (961.7) $ 553.1 $ (28.4) $ 24.3 $ (181.5) $ 39.1 $ (4.0) $ 1.3 Actuarial Losses Reclassified as Net Periodic Benefit Expense (231.2) (194.3) (12.7) (7.7) (8.5) (8.0) (0.4) (0.4) Prior Service Cost Arising During the Year — 2.0 — — — — — — Prior Service (Cost)/Credit Reclassified as Net Periodic (1.3) (1.0) (0.1) (0.2) 21.1 21.3 0.1 (0.1) (1) Amounts include the impact of the CMA asset acquisition beginning October 9, 2020. The following is a summary of the remaining Regulatory Assets and Accumulated Other Comprehensive Income amounts that have not been recognized as components of net periodic benefit expense as of December 31, 2021 and 2020: Regulatory Assets as of December 31, AOCI as of December 31, (Millions of Dollars) 2021 2020 2021 2020 Pension and SERP Actuarial Loss $ 1,427.3 $ 2,620.2 $ 66.3 $ 107.4 Prior Service Cost 5.3 6.6 0.6 0.7 PBOP Actuarial Loss $ 45.0 $ 235.0 $ 3.5 $ 7.9 Prior Service (Credit)/Cost (130.1) (151.2) 1.0 0.9 The difference between the actual return and calculated expected return on plan assets for the Pension and PBOP Plans, as well as changes in actuarial assumptions impacting the projected benefit obligation, are recorded as unamortized actuarial gains or losses arising during the year in Regulatory Assets or Accumulated Other Comprehensive Income/(Loss). Unamortized actuarial gains or losses are amortized as a component of pension and PBOP expense over the estimated average future employee service period. Estimated Future Benefit Payments: The following benefit payments, which reflect expected future service, are expected to be paid by the Pension, SERP and PBOP Plans: (Millions of Dollars) 2022 2023 2024 2025 2026 2027 - 2031 Pension and SERP $ 359.6 $ 367.4 $ 405.0 $ 381.2 $ 384.3 $ 1,918.2 PBOP 56.4 56.2 55.9 55.3 54.3 254.6 Eversource Contributions: Based on the current status of the Pension Plans and federal pension funding requirements, there is no minimum funding requirement for our Pension Plans for 2022. Eversource currently expects to make contributions between $100 million to $175 million in 2022, most of which will be contributed by Eversource Service, however the planned contribution is discretionary and subject to change. Eversource currently estimates contributing $2.4 million to the PBOP Plans in 2022. Fair Value of Pension and PBOP Plan Assets: Pension and PBOP funds are held in external trusts. Trust assets, including accumulated earnings, must be used exclusively for Pension and PBOP payments. Eversource's investment strategy for its Pension and PBOP Plans is to maximize the long-term rates of return on these plans' assets within an acceptable level of risk. The investment strategy for each asset category includes a diversification of asset types, fund strategies and fund managers and it establishes target asset allocations that are routinely reviewed and periodically rebalanced. PBOP assets are comprised of assets held in the PBOP Plan trust, as well as specific assets within the Pension Plan trust (401(h) assets). The investment policy and strategy of the 401(h) assets is consistent with that of the defined benefit pension plan. Eversource's expected long-term rates of return on Pension and PBOP Plan assets are based on target asset allocation assumptions and related expected long-term rates of return. In developing its expected long-term rate of return assumptions for the Pension and PBOP Plans, Eversource evaluated input from consultants, as well as long-term inflation assumptions and historical returns. Management has assumed long-term rates of return of 8.25 percent for the Eversource Service Pension and PBOP Plan assets and a 7 percent long-term rate of return for the Aquarion Plans to estimate its 2022 Pension and PBOP costs. These long-term rates of return are based on the assumed rates of return for the target asset allocations as follows: As of December 31, 2021 2020 Eversource Pension Plan and PBOP Plan Eversource Pension Plan and PBOP Plan Target Asset Allocation Assumed Rate of Return Target Asset Allocation Assumed Rate of Return Equity Securities: United States 15.0 % 8.5 % 15.0 % 8.5 % Global 10.0 % 8.75 % 10.0 % 8.75 % Non-United States 8.0 % 8.5 % 8.0 % 8.5 % Emerging Markets 4.0 % 10.0 % 4.0 % 10.0 % Debt Securities: Fixed Income 13.0 % 4.0 % 13.0 % 4.0 % Public High Yield Fixed Income 4.0 % 6.5 % 4.0 % 6.5 % Private Debt 13.0 % 9.0 % 15.0 % 9.0 % Private Equity 18.0 % 12.0 % 15.0 % 12.0 % Real Assets 15.0 % 7.5 % 16.0 % 7.5 % The following table presents, by asset category, the Pension and PBOP Plan assets recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Pension Plan Fair Value Measurements as of December 31, (Millions of Dollars) 2021 2020 Asset Category: Level 1 Level 2 Uncategorized Total Level 1 Level 2 Uncategorized Total Equity Securities $ 722.5 $ — $ 1,385.2 $ 2,107.7 $ 630.8 $ — $ 1,321.7 $ 1,952.5 Fixed Income 139.6 233.8 1,689.1 2,062.5 113.6 265.6 1,402.5 1,781.7 Private Equity — — 1,702.7 1,702.7 22.3 — 1,175.4 1,197.7 Real Assets 218.3 — 702.8 921.1 158.4 — 580.8 739.2 Total $ 1,080.4 $ 233.8 $ 5,479.8 $ 6,794.0 $ 925.1 $ 265.6 $ 4,480.4 $ 5,671.1 Less: 401(h) PBOP Assets (1) (298.5) (261.9) Total Pension Assets $ 6,495.5 $ 5,409.2 PBOP Plan Fair Value Measurements as of December 31, (Millions of Dollars) 2021 2020 Asset Category: Level 1 Level 2 Uncategorized Total Level 1 Level 2 Uncategorized Total Equity Securities $ 191.4 $ — $ 248.3 $ 439.7 $ 176.5 $ — $ 217.8 $ 394.3 Fixed Income 49.7 45.2 125.5 220.4 16.0 43.2 152.9 212.1 Private Equity — — 58.7 58.7 — — 31.5 31.5 Real Assets 90.0 — 31.0 121.0 82.1 — 22.2 104.3 Total $ 331.1 $ 45.2 $ 463.5 $ 839.8 $ 274.6 $ 43.2 $ 424.4 $ 742.2 Add: 401(h) PBOP Assets (1) 298.5 261.9 Total PBOP Assets $ 1,138.3 $ 1,004.1 (1) The assets of the Pension Plan include a 401(h) account that has been allocated to provide health and welfare postretirement benefits under the PBOP Plan. The Company values assets based on observable inputs when available. Equity securities, exchange traded funds and futures contracts classified as Level 1 in the fair value hierarchy are priced based on the closing price on the primary exchange as of the balance sheet date. Fixed income securities, such as government issued securities and corporate bonds, are included in Level 2 and are valued using pricing models, quoted prices of securities with similar characteristics or discounted cash flows. The pricing models utilize observable inputs such as recent trades for the same or similar instruments, yield curves, discount margins and bond structures. Swaps are valued using pricing models that incorporate interest rates and equity and fixed income index closing prices to determine a net present value of the cash flows. Eversource maintains defined contribution plans on behalf of eligible participants. The Eversource 401k Plan provides for employee and employer contributions up to statutory limits. For eligible employees, the Eversource 401k Plan provides employer matching contributions of either 100 percent up to a maximum of three percent of eligible compensation or 50 percent up to a maximum of eight percent of eligible compensation. The Eversource 401k Plan also contains a K-Vantage feature for the benefit of eligible participants, which provides an additional annual employer contribution based on age and years of service. K-Vantage participants are not eligible to actively participate in the Eversource Pension Plan. The total Eversource 401k Plan employer matching contributions, including the K-Vantage contributions, were as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2021 $ 55.5 $ 7.0 $ 12.2 $ 4.3 2020 49.4 6.6 11.8 4.1 2019 41.6 5.5 10.3 3.5 Share-based compensation awards are recorded using a fair-value based method at the date of grant. Eversource, CL&P, NSTAR Electric and PSNH record compensation expense related to these awards, as applicable, for shares issued to their respective employees and officers, as well as for the allocation of costs associated with shares issued to Eversource's service company employees and officers that support CL&P, NSTAR Electric and PSNH. Eversource Incentive Plans: Eversource maintains long-term equity-based incentive plans in which Eversource, CL&P, NSTAR Electric and PSNH employees, officers and board members are eligible to participate. The incentive plans authorize Eversource to grant up to 6,700,000 new shares for various types of awards, including RSUs and performance shares, to eligible employees, officers, and board members. As of December 31, 2021 and 2020, Eversource had 2,430,716 and 2,876,601 common shares, respectively, available for issuance under these plans. Eversource accounts for its various share-based plans as follows: • RSUs - Eversource records compensation expense, net of estimated forfeitures, on a straight-line basis over the requisite service period based upon the fair value of Eversource's common shares at the date of grant. The par value of RSUs is reclassified to Common Stock from Capital Surplus, Paid In as RSUs become issued as common shares. • Performance Shares - Eversource records compensation expense, net of estimated forfeitures, on a straight-line basis over the requisite service period. Performance shares vest based upon the extent to which Company goals are achieved. Vesting of outstanding performance shares is based upon both the Company's EPS growth over the requisite service period and the total shareholder return as compared to the Edison Electric Institute (EEI) Index during the requisite service period. The fair value of performance shares is determined at the date of grant using a lattice model. RSUs: Eversource granted RSUs under the annual long-term incentive programs that are subject to three-year graded vesting schedules for employees, and one-year graded vesting schedules, or immediate vesting, for board members. RSUs are paid in shares, reduced by amounts sufficient to satisfy withholdings for income taxes, subsequent to vesting. A summary of RSU transactions is as follows: RSUs Weighted Average Outstanding as of December 31, 2020 674,218 $ 63.42 Granted 165,930 $ 81.89 Shares Issued (223,484) $ 69.03 Forfeited (22,041) $ 83.86 Outstanding as of December 31, 2021 594,623 $ 65.70 The weighted average grant-date fair value of RSUs granted for the years ended December 31, 2021, 2020 and 2019 was $81.89, $88.23 and $67.91, respectively. As of December 31, 2021 and 2020, the number and weighted average grant-date fair value of unvested RSUs was 297,270 and $83.39 per share, and 379,258 and $77.13 per share, respectively. During 2021, there were 219,560 RSUs at a weighted average grant-date fair value of $72.37 per share that vested during the year and were either paid or deferred. As of December 31, 2021, 297,353 RSUs were fully vested and deferred and an additional 282,407 are expected to vest. Performance Shares: Eversource granted performance shares under the annual long-term incentive programs that vest based upon the extent to which Company goals are achieved at the end of three-year performance measurement periods. Performance shares are paid in shares, after the performance measurement period. A summary of performance share transactions is as follows: Performance Shares Weighted Average Outstanding as of December 31, 2020 447,805 $ 69.93 Granted 286,645 $ 76.08 Shares Issued (256,914) $ 56.88 Forfeited (13,029) $ 84.28 Outstanding as of December 31, 2021 464,507 $ 80.54 The weighted average grant-date fair value of performance shares granted for the years ended December 31, 2021, 2020 and 2019 was $76.08, $75.36 and $68.33, respectively. As of December 31, 2021 and 2020, the number and weighted average grant-date fair value of unvested performance shares was 436,957 and $81.41 per share, and 404,698 and $70.85 per share, respectively. During 2021, there were 241,949 performance shares at a weighted average grant-date fair value of $57.23 per share that vested during the year and were either paid or deferred. As of December 31, 2021, 27,550 performance shares were fully vested and deferred. Compensation Expense: The total compensation expense and associated future income tax benefits recognized by Eversource, CL&P, NSTAR Electric and PSNH for share-based compensation awards were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Compensation Expense $ 28.2 $ 33.9 $ 27.3 Future Income Tax Benefit 7.3 8.9 7.0 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Compensation Expense $ 8.8 $ 9.0 $ 3.0 $ 10.9 $ 11.3 $ 3.6 $ 9.8 $ 9.7 $ 3.3 Future Income Tax Benefit 2.3 2.3 0.8 2.9 3.0 1.0 2.5 2.5 0.8 As of December 31, 2021, there was $17.8 million of total unrecognized compensation expense related to nonvested share-based awards for Eversource, including $3.2 million for CL&P, $5.0 million for NSTAR Electric, and $1.1 million for PSNH. This cost is expected to be recognized ratably over a weighted-average period of 1.72 years for Eversource, CL&P, NSTAR Electric and PSNH. An income tax rate of 26 percent was used to estimate the tax effect on total share-based payments determined under the fair-value based method for all awards. Beginning in 2019, the Company began issuing treasury shares to settle fully vested RSUs and performance shares under the Company's incentive plans. For the years ended December 31, 2021, 2020 and 2019, excess tax benefits associated with the distribution of stock compensation awards reduced income tax expense by $4.0 million, $6.6 million, and $1.5 million, respectively, which increased cash flows from operating activities on the statements of cash flows. Eversource provides retirement and other benefits for certain current and past company officers. These benefits are accounted for on an accrual basis and expensed over a period equal to the service lives of the employees. The actuarially-determined liability for these benefits is included in Other Current and Long-Term Liabilities on the balance sheets. The related expense, which includes the allocation of expense associated with Eversource's service company officers that support CL&P, NSTAR Electric and PSNH, is included in Operations and Maintenance Expense on the income statements. The liability and expense amounts are as follows: Eversource (Millions of Dollars) As of and For the Years Ended December 31, 2021 2020 2019 Actuarially-Determined Liability $ 42.8 $ 45.7 $ 52.0 Other Retirement Benefits Expense 2.2 3.3 2.7 As of and For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Actuarially-Determined Liability $ 0.2 $ 0.1 $ 1.5 $ 0.2 $ 0.1 $ 1.7 $ 0.2 $ 0.1 $ 1.7 Other Retirement Benefits Expense 0.7 0.7 0.3 1.2 1.1 0.5 1.0 0.9 0.4

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The components of income tax expense are as follows: Eversource (Millions of Dollars) For the Years Ended December 31, 2021 2020 2019 Current Income Taxes: Federal $ 21.5 $ 73.6 $ 56.9 State (21.6) 19.1 10.5 Total Current (0.1) 92.7 67.4 Deferred Income Taxes, Net: Federal 199.7 173.5 138.4 State 147.4 83.7 71.4 Total Deferred 347.1 257.2 209.8 Investment Tax Credits, Net (2.8) (3.7) (3.7) Income Tax Expense $ 344.2 $ 346.2 $ 273.5 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Current Income Taxes: Federal $ 15.0 $ 52.3 $ 43.1 $ 12.0 $ 53.9 $ 20.6 $ 68.4 $ 82.6 $ 22.9 State (7.0) 6.2 10.8 (6.1) 6.9 3.8 15.4 18.2 2.2 Total Current 8.0 58.5 53.9 5.9 60.8 24.4 83.8 100.8 25.1 Deferred Income Taxes, Net: Federal 76.3 16.3 (14.9) 101.1 33.8 (1.3) 35.2 0.1 5.8 State 47.6 41.2 0.4 43.4 38.8 8.6 18.8 27.0 10.1 Total Deferred 123.9 57.5 (14.5) 144.5 72.6 7.3 54.0 27.1 15.9 Investment Tax Credits, Net (0.6) (1.7) — (0.7) (2.6) — (0.8) (2.6) — Income Tax Expense $ 131.3 $ 114.3 $ 39.4 $ 149.7 $ 130.8 $ 31.7 $ 137.0 $ 125.3 $ 41.0 A reconciliation between income tax expense and the expected tax expense at the statutory rate is as follows: Eversource (Millions of Dollars, except percentages) For the Years Ended December 31, 2021 2020 2019 Income Before Income Tax Expense $ 1,572.3 $ 1,558.9 $ 1,190.1 Statutory Federal Income Tax Expense at 21% 330.2 327.4 249.9 Tax Effect of Differences: Depreciation (18.1) (11.1) 1.9 Investment Tax Credit Amortization (2.8) (3.7) (3.7) State Income Taxes, Net of Federal Impact 54.4 44.9 24.6 Dividends on ESOP (5.1) (5.1) (5.1) Tax Asset Valuation Allowance/Reserve Adjustments 44.6 33.4 40.1 Excess Stock Benefit (4.0) (6.6) (1.5) EDIT Amortization (69.1) (48.7) (37.4) Other, Net 14.1 15.7 4.7 Income Tax Expense $ 344.2 $ 346.2 $ 273.5 Effective Tax Rate 21.9 % 22.2 % 23.0 % For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars, except percentages) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Income Before Income Tax Expense $ 533.0 $ 590.9 $ 189.8 $ 607.6 $ 575.8 $ 179.0 $ 547.8 $ 557.3 $ 175.0 Statutory Federal Income Tax Expense at 21% 111.9 124.1 39.9 127.6 120.9 37.6 115.0 117.0 36.8 Tax Effect of Differences: Depreciation (6.4) (3.4) (0.2) 0.4 (3.7) (1.4) (0.2) (3.0) (0.8) Investment Tax Credit Amortization (0.6) (1.7) — (0.7) (2.6) — (0.8) (2.6) — State Income Taxes, Net of Federal Impact (4.6) 37.5 8.9 (1.2) 36.0 9.8 2.5 35.7 9.8 Tax Asset Valuation 36.7 — — 30.7 — — 24.5 — — Excess Stock Benefit (1.5) (1.4) (0.5) (2.3) (2.3) (0.8) (0.5) (0.5) (0.2) EDIT Amortization (9.8) (43.2) (10.5) (9.0) (20.4) (15.4) (5.8) (22.9) (4.0) Other, Net 5.6 2.4 1.8 4.2 2.9 1.9 2.3 1.6 (0.6) Income Tax Expense $ 131.3 $ 114.3 $ 39.4 $ 149.7 $ 130.8 $ 31.7 $ 137.0 $ 125.3 $ 41.0 Effective Tax Rate 24.6 % 19.3 % 20.8 % 24.6 % 22.7 % 17.7 % 25.0 % 22.5 % 23.4 % Eversource, CL&P, NSTAR Electric and PSNH file a consolidated federal income tax return and unitary, combined and separate state income tax returns. These entities are also parties to a tax allocation agreement under which taxable subsidiaries do not pay any more taxes than they would have otherwise paid had they filed a separate company tax return, and subsidiaries generating tax losses, if any, are paid for their losses when utilized. Deferred tax assets and liabilities are recognized for the future tax effects of temporary differences between the carrying amounts and the tax basis of assets and liabilities. The tax effect of temporary differences is accounted for in accordance with the rate-making treatment of the applicable regulatory commissions and relevant accounting authoritative literature. The tax effects of temporary differences that give rise to the net accumulated deferred income tax obligations are as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Deferred Tax Assets: Employee Benefits $ 270.8 $ 23.9 $ 40.3 $ 14.1 $ 602.4 $ 144.5 $ 79.8 $ 56.6 Derivative Liabilities 76.8 76.8 — — 92.6 91.8 — — Regulatory Deferrals - Liabilities 390.7 90.9 215.4 24.3 259.8 30.2 161.8 13.4 Allowance for Uncollectible Accounts 104.1 48.8 21.5 6.2 87.5 42.3 20.9 4.6 Tax Effect - Tax Regulatory Liabilities 783.4 328.2 254.3 100.9 810.9 331.4 271.8 105.2 Net Operating Loss Carryforwards 7.5 — — — 12.7 — — — Purchase Accounting Adjustment 67.2 — — — 54.5 — — — Other 196.6 103.9 21.7 22.9 200.3 100.9 14.3 19.8 Total Deferred Tax Assets 1,897.1 672.5 553.2 168.4 2,120.7 741.1 548.6 199.6 Less: Valuation Allowance 61.5 44.5 — — 48.3 33.7 — — Net Deferred Tax Assets $ 1,835.6 $ 628.0 $ 553.2 $ 168.4 $ 2,072.4 $ 707.4 $ 548.6 $ 199.6 Deferred Tax Liabilities: Accelerated Depreciation and Other $ 4,426.0 $ 1,509.5 $ 1,553.7 $ 482.9 $ 4,153.6 $ 1,438.1 $ 1,489.4 $ 453.8 Property Tax Accruals 88.1 40.5 33.7 6.3 88.7 39.0 37.0 5.8 Regulatory Amounts: Regulatory Deferrals - Assets 1,260.3 438.3 337.6 198.4 1,376.7 444.8 324.4 263.4 Tax Effect - Tax Regulatory Assets 257.8 181.4 10.9 8.3 244.6 174.4 11.3 8.6 Goodwill Regulatory Asset - 1999 Merger 81.4 — 69.9 — 86.0 — 73.8 — Derivative Assets 14.9 14.9 — — 17.8 17.8 — — Other 304.2 5.5 126.9 10.5 200.3 1.6 72.6 5.6 Total Deferred Tax Liabilities $ 6,432.7 $ 2,190.1 $ 2,132.7 $ 706.4 $ 6,167.7 $ 2,115.7 $ 2,008.5 $ 737.2 2021 Federal Legislation: On November 5, 2021, Congress passed the Infrastructure Investment and Jobs Act. The Act provided spending of more than $500 billion on roads, highways, bridges, public transit, and utilities. For water and sewer utilities, the Act restored the exclusion from a corporation’s income for contributions in aid of construction where the corporation is a water or sewer utility eliminated by the Tax Cuts and Jobs Act of 2017. Under the Act, a regulated public utility that provides water or sewage disposal services can treat money or property received from any person as a tax-free contribution to capital if it meets certain criteria for contributions made after 2020. The Act did not have a material impact on Eversource in 2021. 2020 Federal Legislation: On March 27, 2020, former President Trump signed the $2.2 trillion bipartisan Coronavirus Aid, Relief, and Economic Security (CARES) Act. Among other provisions, the CARES Act provides for loans and other benefits to small and large businesses, expanded unemployment insurance, direct payments to those with wages middle-income and below, new appropriations funding for health care and other priorities, and tax changes like deferrals of employer payroll tax liabilities coupled with an employee retention tax credit and rollbacks of Tax Cuts and Jobs Act of 2017 limitations on net operating losses and certain business interest limitation. For the years ended December 31, 2021 and 2020, we recorded a tax liability of $19.6 million and $39 million, respectively, related to the deferral of employer payroll tax liability provision. Fifty percent of the 2020 deferral of employer payroll tax liability was paid by December 31, 2021 and the remaining amount must be paid by December 31, 2022. Other than the cash flow benefit described, the CARES Act did not have a material impact. On December 27, 2020, former President Trump signed into law H.R. 133, the “Consolidated Appropriations Act, 2021.” The House of Representatives and Senate previously passed the bill with overwhelming support. The legislation included the extension of the Investment Tax Credit (ITC) for solar at 26 percent for facilities the construction of which begins through the end of 2022, at 22 percent for facilities the construction of which begins in 2023, and postponement of the date after which solar facilities placed in service receive only a 10 percent ITC to December 31, 2025, the extension of the ITC at 30 percent (with no phase-down) to offshore wind if construction begins by December 31, 2025 (qualifying offshore wind includes facilities located in the inland navigable waters or in the coastal waters of the U.S.), and the extension and expansion of the CARES Act employee retention tax credit for the period from January 1, 2021 through June 30, 2021, including increasing the credit rate from 50 percent to 70 percent of qualified wages, and increasing the per-employee creditable wages limit from $10,000 per year to $10,000 for each quarter. These credits provide the opportunity to generate additional tax credits in the Company’s renewable energy projects when the projects become operational. The tax credit provision had no impact to Eversource in 2021 and the credits will be evaluated for significant positive developments for the Company in 2022 and forward. Carryforwards: The following table provides the amounts and expiration dates of state tax credit and loss carryforwards and federal tax credit and net operating loss carryforwards: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Expiration Range Eversource CL&P NSTAR PSNH Expiration Range State Net Operating Loss $ 138.3 $ — $ — $ — 2021 - 2040 $ 183.4 $ — $ — $ — 2021 - 2040 State Tax Credit 197.7 137.0 — — 2021 - 2026 186.6 133.4 — — 2020 - 2025 State Charitable Contribution 23.7 — — — 2021 - 2025 10.2 — — — 2020 - 2024 In 2021, the Company increased its valuation allowance reserve for state credits by $13.0 million ($10.8 million for CL&P), net of tax, to reflect an update for expiring tax credits. In 2020 , the Company increased its valuation allowance reserve for state credits by $10.3 million ($8.8 million for CL&P), net of tax, to reflect an update for expiring tax credits. For 2021 and 2020, state credit and state loss carryforwards have been partially reserved by a valuation allowance of $61.5 million and $48.3 million (net of tax), respectively. Unrecognized Tax Benefits: A reconciliation of the activity in unrecognized tax benefits, all of which would impact the effective tax rate if recognized, is as follows: (Millions of Dollars) Eversource CL&P Balance as of January 1, 2019 $ 45.9 $ 18.2 Gross Increases - Current Year 12.1 4.0 Gross Increases - Prior Year 3.4 3.3 Lapse of Statute of Limitations (6.4) (2.4) Balance as of December 31, 2019 55.0 23.1 Gross Increases - Current Year 11.9 4.6 Gross Increases - Prior Year 1.4 0.7 Lapse of Statute of Limitations (6.5) (2.6) Balance as of December 31, 2020 61.8 25.8 Gross Increases - Current Year 11.3 3.8 Gross Decreases - Prior Year (0.3) (0.6) Lapse of Statute of Limitations (7.0) (2.8) Balance as of December 31, 2021 $ 65.8 $ 26.2 Interest and Penalties: Interest on uncertain tax positions is recorded and generally classified as a component of Other Interest Expense on the statements of income. However, when resolution of uncertainties results in the Company receiving interest income, any related interest benefit is recorded in Other Income, Net on the statements of income. No penalties have been recorded. There has been no interest expense or income recognized on uncertain tax positions for the years ended December 31, 2021, 2020 or 2019. The accrued interest payable was $0.1 million as of both December 31, 2021 and 2020. Tax Positions: During 2021 and 2020, Eversource did not resolve any of its uncertain tax positions. Open Tax Years: The following table summarizes Eversource, CL&P, NSTAR Electric, and PSNH's tax years that remain subject to examination by major tax jurisdictions as of December 31, 2021: Description Tax Years Federal 2021 Connecticut 2018 - 2021 Massachusetts 2018 - 2021 New Hampshire 2018 - 2021 Eversource does not estimate to have an earnings impact related to unrecognized tax benefits during the next twelve months.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2021
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. Environmental reserves are accrued when assessments indicate it is probable that a liability has been incurred and an amount can be reasonably estimated. The approach used estimates the liability based on the most likely action plan from a variety of available remediation options, including no action required or several different remedies ranging from establishing institutional controls to full site remediation and monitoring. These liabilities are estimated on an undiscounted basis and do not assume that the amounts are recoverable from insurance companies or other third parties. The environmental reserves include sites at different stages of discovery and remediation and do not include any unasserted claims. 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. The amounts recorded as environmental reserves are included in Other Current Liabilities and Other Long-Term Liabilities on the balance sheets and represent management's best estimate of the liability for environmental costs, and take into consideration site assessment, remediation and long-term monitoring costs. The environmental reserves also take into account recurring costs of managing hazardous substances and pollutants, mandated expenditures to remediate contaminated sites and any other infrequent and non-recurring clean-up costs. A reconciliation of the activity in the environmental reserves is as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Balance as of January 1, 2020 $ 81.0 $ 11.4 $ 8.0 $ 7.5 Increase Due to CMA Asset Acquisition 22.9 — — — Additions 8.4 4.2 0.7 — Payments/Reductions (9.9) (3.3) (4.0) (0.4) Balance as of December 31, 2020 102.4 12.3 4.7 7.1 Additions 23.4 4.4 — — Payments/Reductions (10.4) (2.8) (1.4) (0.8) Balance as of December 31, 2021 $ 115.4 $ 13.9 $ 3.3 $ 6.3 The number of environmental sites for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: Eversource CL&P NSTAR Electric PSNH 2021 61 14 11 9 2020 63 15 12 9 The increase in the reserve balance was due primarily to a change in cost estimates at an NSTAR Gas MGP site under investigation, which we now know will require additional remediation. Included in the number of sites and reserve amounts above are former MGP sites that were operated several decades ago and manufactured natural 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 $105.6 million and $92.2 million as of December 31, 2021 and 2020, respectively, and related primarily to the natural gas business segment. As of December 31, 2021, for 7 environmental sites (2 for CL&P) that are included in the Company's reserve for environmental costs, the information known and the nature of the remediation options allow for the Company to estimate the range of losses for environmental costs. As of December 31, 2021, $25.9 million (including $3.2 million for CL&P) has been accrued as a liability for these sites, which represents the low end of the range of the liabilities for environmental costs. Management believes that additional losses of up to approximately $10 million ($0.6 million at CL&P) may be incurred in executing current remediation plans for these sites. As of December 31, 2021, for 13 environmental sites (7 for CL&P and 2 for NSTAR Electric) that are included in the Company's reserve for environmental costs, management cannot reasonably estimate the exposure to loss in excess of the reserve, or range of loss, as these sites are under investigation and/or there is significant uncertainty as to what remedial actions, if any, the Company may be required to undertake. As of December 31, 2021, $16.1 million (including $3.9 million for CL&P and $0.2 million for NSTAR Electric) had been accrued as a liability for these sites. As of December 31, 2021, for the remaining 41 environmental sites (including 5 for CL&P, 9 for NSTAR Electric and 9 for PSNH) that are included in the Company's reserve for environmental costs, the $73.4 million accrual (including $6.8 million for CL&P, $3.1 million for NSTAR Electric and $6.3 million for PSNH) represents management's best estimate of the probable liability and no additional loss is estimable at this time. Estimated Future Annual Costs: The estimated future annual costs of significant executed, non-cancelable, long-term contractual arrangements in effect as of December 31, 2021 are as follows: Eversource (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 755.4 $ 700.7 $ 696.4 $ 718.7 $ 714.3 $ 3,571.4 $ 7,156.9 Natural Gas Procurement 377.9 323.6 270.5 265.5 250.4 1,517.2 3,005.1 Purchased Power and Capacity 76.0 87.1 86.7 75.1 2.9 9.8 337.6 Peaker CfDs 26.1 38.9 39.4 36.7 29.9 63.3 234.3 Transmission Support Commitments 16.0 17.8 20.6 22.4 22.6 22.6 122.0 Total $ 1,251.4 $ 1,168.1 $ 1,113.6 $ 1,118.4 $ 1,020.1 $ 5,184.3 $ 10,855.9 CL&P (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 586.2 $ 592.1 $ 592.0 $ 593.9 $ 591.9 $ 2,752.2 $ 5,708.3 Purchased Power and Capacity 72.1 83.4 83.8 72.3 0.1 — 311.7 Peaker CfDs 26.1 38.9 39.4 36.7 29.9 63.3 234.3 Transmission Support Commitments 6.3 7.0 8.1 8.8 8.9 8.9 48.0 Total $ 690.7 $ 721.4 $ 723.3 $ 711.7 $ 630.8 $ 2,824.4 $ 6,302.3 NSTAR Electric (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 102.9 $ 78.3 $ 75.7 $ 76.1 $ 76.4 $ 492.3 $ 901.7 Purchased Power and Capacity 3.0 2.9 2.9 2.8 2.8 9.8 24.2 Transmission Support Commitments 6.3 7.0 8.1 8.9 8.9 8.9 48.1 Total $ 112.2 $ 88.2 $ 86.7 $ 87.8 $ 88.1 $ 511.0 $ 974.0 PSNH (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 66.3 $ 30.3 $ 28.7 $ 48.7 $ 46.0 $ 326.9 $ 546.9 Purchased Power and Capacity 0.9 0.8 — — — — 1.7 Transmission Support Commitments 3.4 3.8 4.4 4.7 4.8 4.8 25.9 Total $ 70.6 $ 34.9 $ 33.1 $ 53.4 $ 50.8 $ 331.7 $ 574.5 Renewable Energy: Renewable energy contracts include non-cancellable commitments under contracts of CL&P, NSTAR Electric and PSNH for the purchase of energy and capacity from renewable energy facilities. Such contracts extend through 2042 for CL&P, 2041 for NSTAR Electric and 2033 for PSNH. As required by 2018 regulation, CL&P and UI each entered into PURA-approved ten-year contracts in 2019 to purchase a combined total of approximately 9 million MWh annually from the Millstone Nuclear Power Station generation facility, which represents 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. Energy deliveries and payments under these contracts began in 2019. Also as required by 2018 regulation, CL&P and UI each entered into PURA-approved eight-year contracts in 2019 to purchase a combined amount of approximately 18 percent of the Seabrook Nuclear Power Plant’s output (approximately 15 percent by CL&P) beginning January 1, 2022. The Seabrook Nuclear Power Plant has an approximate 1,250 MW nameplate capacity. The total estimated remaining future cost of the Millstone Nuclear Power Station and Seabrook Nuclear Power Plant energy purchase contracts are $3.3 billion and are reflected in the table above. CL&P sells the energy purchased under these contracts into the market and uses the proceeds from these energy sales to offset the contract costs. As the net costs under these contracts are recovered from customers in future rates, the contracts do not have an impact on the net income of CL&P. These contracts do not meet the definition of a derivative, and accordingly, the costs of these contracts are being accounted for as incurred. Excluded from the table above are long-term commitments of NSTAR Electric pertaining to the Massachusetts Clean Energy 83D contract, for which construction was suspended prior to December 31, 2021. Should the project attain feasibility and construction recommence, the estimated costs under the contract may potentially begin in 2023 and range between $150 million and $415 million per year under a 20-year contract, totaling approximately $6.7 billion. The contractual obligations table above does not include long-term commitments signed by CL&P and NSTAR Electric, as required by the PURA and DPU, respectively, for the purchase of renewable energy and related products that are contingent on the future construction of energy facilities. Natural Gas Procurement: Eversource's natural gas distribution businesses have long-term contracts for the purchase, transportation and storage of natural gas as part of its portfolio of supplies, which extend through 2045. Purchased Power and Capacity: These contracts include capacity CfDs of CL&P through 2026, and various IPP contracts or purchase obligations for electricity which extend through 2024 for CL&P, 2031 for NSTAR Electric and 2023 for PSNH. 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 both December 31, 2021 and 2020 were 675 MW. 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. CL&P's portion of the costs and benefits of these contracts will be paid by, or refunded to, CL&P's customers. The contractual obligations table above does not include CL&P's, NSTAR Electric's or PSNH's standard/basic service contracts for the purchase of energy supply, the amounts of which vary with customers' energy needs. Peaker CfDs: CL&P, along with UI, has three peaker CfDs for a total of approximately 500 MW of peaking capacity through 2042. CL&P has a sharing agreement with UI, whereby CL&P is responsible for 80 percent and UI for 20 percent of the net costs or benefits of these CfDs. The Peaker CfDs pay the generation facility owner the difference between capacity, forward reserve and energy market revenues and a cost-of-service payment stream for 30 years. The ultimate cost or benefit to CL&P under these contracts will depend on the costs of plant operation and the prices that the projects receive for capacity and other products in the ISO-NE markets. CL&P's portion of the amounts paid or received under the Peaker CfDs are recovered from, or refunded to, CL&P's customers. Transmission Support Commitments: Along with other New England utilities, CL&P, NSTAR Electric and PSNH entered into a series of agreements in the 1980’s to support the costs of, and receive rights to use, transmission and terminal facilities that were built to import electricity from the Hydro-Québec system in Canada. CL&P, NSTAR Electric and PSNH were obligated to pay, over a 30-year period that ended in 2020, their proportionate shares of the annual operation and maintenance expenses and capital costs of those facilities. On December 18, 2020, the parties to these agreements submitted to FERC an offer of settlement and amendments to these agreements implementing the terms of an extension for an additional 20-year period ending in 2040. On May 20, 2021, FERC approved this settlement, effective January 1, 2021. The total costs incurred under these agreements were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Renewable Energy $ 609.2 $ 584.2 $ 320.8 Natural Gas Procurement 712.7 453.4 448.5 Purchased Power and Capacity 56.4 62.7 62.1 Peaker CfDs 24.3 22.7 13.0 Transmission Support Commitments 15.4 22.1 21.8 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Renewable Energy $ 457.1 $ 84.7 $ 67.4 $ 426.3 $ 88.8 $ 69.1 $ 160.6 $ 89.9 $ 70.3 Purchased Power and Capacity 53.1 3.0 0.3 59.3 3.1 0.3 50.4 5.1 6.6 Peaker CfDs 24.3 — — 22.7 — — 13.0 — — Transmission Support Commitments 6.1 6.0 3.3 8.7 8.7 4.7 8.6 8.6 4.6 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 power 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 accept delivery of, and 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 previously awarded the Yankee Companies damages for Phases I, II, III and IV of litigation resulting from the DOE's failure to meet its contractual obligations. These Phases covered damages incurred in the years 1998 through 2016, 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 a fourth set of 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, each of the Yankee Companies received the damages proceeds. 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, for which approval was received in the fourth quarter of 2019. In December 2019, YAEC and MYAPC returned proceeds of $5.4 million and $21.0 million, respectively, to its member companies, of which the Eversource utilities (CL&P, NSTAR Electric and PSNH) received a total of $2.8 million from YAEC and $5.0 million from MYAPC. The Eversource utilities refund these amounts received to their utility customers. Also, in December 2019, CYAPC paid $29.0 million to the DOE to partially settle its pre-1983 spent nuclear fuel obligation. DOE Phase V Damages - On March 25, 2021, each of the Yankee Companies filed a fifth set of lawsuits against the DOE in the Court of Federal Claims. The Yankee Companies filed claims seeking monetary damages totaling $120.4 million for CYAPC, YAEC and MYAPC, resulting from the DOE's failure to begin accepting spent nuclear fuel for disposal covering the years from 2017 to 2020 (DOE Phase V). The DOE Phase V trial is expected to begin in the third quarter of 2023. 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. Management does not anticipate a material impact to net income or cash flows as a result of these various guarantees and indemnifications. Guarantees issued on behalf of unconsolidated entities, including equity method offshore wind investments, for which Eversource parent is the guarantor, are recorded at fair value as a liability on the balance sheet at the inception of the guarantee. Eversource regularly reviews performance risk under these guarantee arrangements, and in the event it becomes probable that Eversource parent will be required to perform under the guarantee, the amount of probable payment will be recorded. The fair value of guarantees issued on behalf of unconsolidated entities are recorded within Other Long-Term Liabilities on the balance sheet, and was $7.3 million as of December 31, 2021. The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries and affiliates to external parties: As of December 31, 2021 Company (Obligor) Description Maximum Exposure Expiration Dates North East Offshore LLC Construction-related purchase agreements with third-party contractors (1) $ 1,080.6 (1) Sunrise Wind LLC Construction-related purchase agreements with third-party contractors (2) 382.3 2026 Revolution Wind, LLC Construction-related purchase agreements with third-party contractors (3) 150.9 2027 South Fork Wind, LLC Construction-related purchase agreements with third-party contractors (4) 125.2 2023 - 2026 Eversource Investment LLC Funding and indemnification obligations of North East Offshore LLC (5) — (5) Sunrise Wind LLC OREC capacity production (6) 2.2 (6) Bay State Wind LLC Real estate purchase 2.5 2022 South Fork Wind, LLC Transmission interconnection 1.2 — Various Surety bonds (7) 54.7 2022 - 2023 Eversource Service Lease payments for real estate 0.8 2024 (1) Eversource parent issued guarantees on behalf of its 50 percent-owned affiliate, North East Offshore LLC (NEO), under which Eversource parent agreed to guarantee 50 percent of NEO’s performance of obligations under certain purchase agreements with third-party contactors, in an aggregate amount not to exceed $1.3 billion with an expiration date in 2025. Eversource parent also issued a separate guarantee to Ørsted on behalf of NEO, under which Eversource parent agreed to guarantee 50 percent of NEO’s payment obligations under certain offshore wind project construction-related agreements with Ørsted in an aggregate amount not to exceed $62.5 million and expiring upon full performance of the guaranteed obligation. Any amounts paid under this guarantee to Ørsted will count toward, but not increase, the maximum amount of the Funding Guarantee described in Note 5, below. The guarantee expires upon the full performance of the guaranteed obligations. (2) Eversource parent issued a guaranty on behalf of its 50 percent-owned affiliate, Sunrise Wind LLC, whereby Eversource parent will guarantee Sunrise Wind LLC's performance of certain obligations, in an aggregate amount not to exceed $420.6 million, in connection with a construction-related purchase agreement. Eversource parent’s obligations under the guarantee expire upon the earlier of (i) April 2026 and (ii) full performance of the guaranteed obligations. (3) Eversource parent issued a guaranty on behalf of its 50 percent-owned affiliate, Revolution Wind, LLC, whereby Eversource parent will guarantee Revolution Wind, LLC's performance of certain obligations, in an aggregate amount not to exceed $158.9 million, in connection with a construction-related purchase agreement. Eversource parent’s obligations under the guarantee expire upon the earlier of (i) November 2027 and (ii) full performance of the guaranteed obligations. (4) Eversource parent issued three guarantees on behalf of its 50 percent-owned affiliate, South Fork Wind, LLC, whereby Eversource parent will guarantee South Fork Wind, LLC's performance of certain obligations in connection with three construction-related purchase agreements. Under these guarantees, Eversource parent will guarantee South Fork Wind, LLC's performance of certain obligations, in a total aggregate amount not to exceed $137.2 million. Eversource parent’s obligations under these guarantees expire upon the earlier of (i) dates ranging from October 2023 and August 2026 and (ii) full performance of the guaranteed obligations. (5) Eversource parent issued a guarantee (Funding Guarantee) on behalf of Eversource Investment LLC (EI), its wholly-owned subsidiary that holds a 50 percent ownership interest in NEO, under which Eversource parent agreed to guarantee certain funding obligations and certain indemnification payments of EI under the Amended and Restated Limited Liability Company Operating Agreement of NEO, in an amount not to exceed $910 million. The guaranteed obligations include payment of EI's funding obligations during the construction phase of NEO’s underlying offshore wind projects and indemnification obligations associated with third party credit support for its investment in NEO. Eversource parent’s obligations under the Funding Guarantee expire upon the full performance of the guaranteed obligations. (6) Eversource parent issued a guarantee on behalf of its 50 percent-owned affiliate, Sunrise Wind LLC, whereby Eversource parent will guarantee 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. The guarantee expires upon the full performance of the guaranteed obligations. (7) 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. Letter of Credit : On September 16, 2020, Eversource parent entered into a guarantee on behalf of EI, which holds Eversource's investments in offshore wind-related equity method investments, under which Eversource parent would guarantee EI's obligations under a letter of credit facility with a financial institution that EI may request in an aggregate amount of up to approximately $25 million. In January 2022, Eversource parent issued two letters of credit on behalf of South Fork Wind, LLC related to future decommissioning obligations of certain on-shore transmission assets totaling $4.3 million. 2022 Guarantees : In the first quarter of 2022, Eversource parent issued two additional guarantees on behalf of South Fork Wind, LLC totaling $43.4 million, whereby Eversource parent will guarantee South Fork Wind, LLC's performance of certain PPA and other contractual obligations. Four separate complaints were 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 both December 31, 2021 and 2020. 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 both December 31, 2021 and 2020. 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. 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 illustrative calculations indicated that for the first complaint period, for the NETOs, which FERC concludes are of average financial risk, the preliminary just and reasonable base ROE is 10.41 percent and the preliminary incentive cap on total ROE is 13.08 percent. If the results of the 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. These preliminary calculations are not binding and do not represent what we believe to be the most likely outcome of a final FERC order. On November 21, 2019, FERC issued Opinion No. 569 affecting the two pending transmission ROE complaints against the Midcontinent ISO (MISO) transmission owners, in which FERC adopted a new methodology for determining base ROEs. Various parties sought rehearing. On December 23, 2019, the NETOs filed supplementary materials in the NETOs' four pending cases to respond to this new methodology because of the uncertainty of the applicability to the NETOs' cases. On May 21, 2020, the FERC issued its order in Opinion No. 569-A on the rehearing of the MISO transmission owners' cases, in which FERC again changed its methodology for determining the MISO transmission owners' base ROEs. On November 19, 2020, the FERC issued Opinion No. 569-B denying rehearing of Opinion No. 569-A and reaffirmed the methodology previously adopted in Opinion No. 569-A. The new methodology differs significantly from the methodology proposed by FERC in its October 16, 2018 order to determine the NETOs' base ROEs in its four pending cases. FERC Opinion Nos. 569-A and 569-B are currently under appeal with the Court. Given the significant uncertainty regarding the applicability of the FERC opinions in the MISO transmission owners' two complaint cases to the NETOs' pending four complaint cases, Eversource concluded that there is no reasonable basis for a change to the reserve or recognized ROEs for any of the complaint periods at this time. As well, Eversource cannot reasonably estimate a range of any gain or loss for any of the four complaint proceedings at this time. 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. A change of 10 basis points to the base ROE used to establish the reserves would impact Eversource’s after-tax earnings by an average of approximately $3 million for each of the four 15-month complaint periods. F. Eversource and NSTAR Electric Boston Harbor Civil Action In 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 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 parties reached a settlement pursuant to which HEEC agreed to install a new 115kV distribution cable across Boston Harbor to Deer Island, utilizing a different route, and remove portions of the existing cable. Construction of the new distribution cable was completed in August 2019 and removal of the portions of the existing cable was completed in January 2020. All issues surrounding the current permit from the United States Army Corps of Engineers are expected to be resolved and remaining restoration efforts completed, at which time such litigation is expected to be dismissed with prejudice. G. CL&P Regulatory Matters CL&P Tropical Storm Isaias Response Investigation: In August 2020, PURA opened a docket to investigate the preparation for and response to Tropical Storm Isaias by Connecticut utilities, including CL&P. On April 28, 2021, PURA issued a final decision on CL&P’s compliance with its emergency response plan that concluded CL&P failed to comply with certain storm performance standards and was imprudent in certain instances. Specifically, PURA concluded that CL&P did not satisfy the performance standards for managing its municipal liaison program, timely removing electrical hazards from blocked roads, communicating critical information to its customers, or meeting its obligation to secure adequate external contractor and mutual aid resources in a timely manner. Based on its findings, PURA ordered CL&P to adjust its future rates in a pending or future rate proceeding to reflect a monetary penalty i

LEASES

LEASES	12 Months Ended
	Dec. 31, 2021
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 because 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 is included as variable lease cost in the table below. The expense and long-term obligation for these contracts are also included in Note 13B, "Commitments and Contingencies - Long-Term Contractual Arrangements," to the financial statements. The components of lease cost, prior to amounts capitalized, are as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Finance Lease Cost: Amortization of Right-of-use-Assets $ 4.6 $ 2.6 $ 1.7 Interest on Lease Liabilities 3.9 1.4 1.2 Total Finance Lease Cost 8.5 4.0 2.9 Operating Lease Cost 12.2 11.1 11.7 Variable Lease Cost 61.0 57.8 60.5 Total Lease Cost $ 81.7 $ 72.9 $ 75.1 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Finance Lease Cost: Amortization of Right-of-use-Assets $ 0.5 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 Interest on Lease Liabilities 0.1 0.6 — 0.3 0.6 — 0.6 0.6 — Total Finance Lease Cost 0.6 0.8 0.1 1.0 0.8 0.1 1.3 0.8 0.1 Operating Lease Cost 0.3 2.3 0.1 0.6 2.1 0.1 0.5 3.4 0.1 Variable Lease Cost 16.2 — 44.8 12.2 — 45.6 13.3 — 47.2 Total Lease Cost $ 17.1 $ 3.1 $ 45.0 $ 13.8 $ 2.9 $ 45.8 $ 15.1 $ 4.2 $ 47.4 Operating lease cost, net of the capitalized portion, is included in Operations and Maintenance (or Purchased Power, Fuel and Transmission expense for transmission 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 on the statements of income. Supplemental balance sheet information related to leases is as follows: As of December 31, 2021 As of December 31, 2020 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Operating Leases: Right-of-use-Assets, Net Other Long-Term Assets $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Operating Lease Liabilities Current Portion Other Current Liabilities $ 10.0 $ 0.1 $ 1.1 $ — $ 9.5 $ 0.2 $ 0.7 $ — Long-Term Other Long-Term Liabilities 37.2 — 23.2 0.3 45.7 0.1 22.9 0.3 Total Operating Lease Liabilities $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Finance Leases: Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 58.0 $ — $ 3.3 $ 0.7 $ 60.5 $ 0.7 $ 3.5 $ 0.8 Finance Lease Liabilities Current Portion Other Current Liabilities $ 3.9 $ — $ — $ 0.1 $ 5.0 $ 1.4 $ — $ 0.1 Long-Term Other Long-Term Liabilities 55.4 — 4.9 0.6 57.6 — 4.8 0.7 Total Finance Lease Liabilities $ 59.3 $ — $ 4.9 $ 0.7 $ 62.6 $ 1.4 $ 4.8 $ 0.8 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: As of December 31, 2021 2020 Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Weighted-Average Remaining Lease Term (Years): Operating Leases 13 7 18 7 10 3 19 8 Finance Leases 16 — 20 7 17 1 21 8 Weighted-Average Discount Rate (Percentage): Operating Leases 4.1 % 3.0 % 4.0 % 3.7 % 4.0 % 2.4 % 4.1 % 3.7 % Finance Leases 2.7 % — % 2.9 % 3.5 % 2.9 % 10.5 % 2.9 % 3.5 % (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2021 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 12.1 $ 0.3 $ 2.1 $ 0.1 Operating Cash Flows from Finance Leases 3.4 0.1 0.6 — Financing Cash Flows from Finance Leases 4.1 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.1 — 1.9 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.3 — — — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2020 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 10.9 $ 0.6 $ 1.8 $ 0.1 Operating Cash Flows from Finance Leases 1.7 0.3 0.6 — Financing Cash Flows from Finance Leases 2.8 1.6 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.6 0.1 0.2 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 0.7 — 0.3 — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 11.4 $ 0.4 $ 1.6 $ 0.1 Operating Cash Flows from Finance Leases 1.2 0.6 0.6 — Financing Cash Flows from Finance Leases 2.6 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.9 1.0 0.1 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.0 — — — In 2020, Eversource also acquired $14.7 million of right-of-use assets in exchange for the assumption of new operating lease liabilities and $54.2 million of right-of-use assets in exchange for the assumption of new finance lease liabilities as a result of the CMA asset acquisition. Future minimum lease payments, excluding variable costs, under long-term leases, as of December 31, 2021 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource NSTAR Electric PSNH Year Ending December 31, 2022 $ 11.1 $ 0.1 $ 2.1 $ 0.1 $ 6.0 $ 0.6 $ 0.1 2023 7.6 — 2.1 0.1 5.2 0.7 0.1 2024 6.1 — 2.1 — 5.3 0.7 0.1 2025 3.2 — 1.7 — 5.2 0.6 0.1 2026 2.5 — 1.7 — 4.7 0.6 0.1 Thereafter 27.8 — 25.3 0.1 56.0 12.4 0.3 Future lease payments 58.3 0.1 35.0 0.3 82.4 15.6 0.8 Less amount representing interest 11.1 — 10.7 — 23.1 10.7 0.1 Present value of future minimum lease payments $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 59.3 $ 4.9 $ 0.7
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 because 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 is included as variable lease cost in the table below. The expense and long-term obligation for these contracts are also included in Note 13B, "Commitments and Contingencies - Long-Term Contractual Arrangements," to the financial statements. The components of lease cost, prior to amounts capitalized, are as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Finance Lease Cost: Amortization of Right-of-use-Assets $ 4.6 $ 2.6 $ 1.7 Interest on Lease Liabilities 3.9 1.4 1.2 Total Finance Lease Cost 8.5 4.0 2.9 Operating Lease Cost 12.2 11.1 11.7 Variable Lease Cost 61.0 57.8 60.5 Total Lease Cost $ 81.7 $ 72.9 $ 75.1 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Finance Lease Cost: Amortization of Right-of-use-Assets $ 0.5 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 Interest on Lease Liabilities 0.1 0.6 — 0.3 0.6 — 0.6 0.6 — Total Finance Lease Cost 0.6 0.8 0.1 1.0 0.8 0.1 1.3 0.8 0.1 Operating Lease Cost 0.3 2.3 0.1 0.6 2.1 0.1 0.5 3.4 0.1 Variable Lease Cost 16.2 — 44.8 12.2 — 45.6 13.3 — 47.2 Total Lease Cost $ 17.1 $ 3.1 $ 45.0 $ 13.8 $ 2.9 $ 45.8 $ 15.1 $ 4.2 $ 47.4 Operating lease cost, net of the capitalized portion, is included in Operations and Maintenance (or Purchased Power, Fuel and Transmission expense for transmission 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 on the statements of income. Supplemental balance sheet information related to leases is as follows: As of December 31, 2021 As of December 31, 2020 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Operating Leases: Right-of-use-Assets, Net Other Long-Term Assets $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Operating Lease Liabilities Current Portion Other Current Liabilities $ 10.0 $ 0.1 $ 1.1 $ — $ 9.5 $ 0.2 $ 0.7 $ — Long-Term Other Long-Term Liabilities 37.2 — 23.2 0.3 45.7 0.1 22.9 0.3 Total Operating Lease Liabilities $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Finance Leases: Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 58.0 $ — $ 3.3 $ 0.7 $ 60.5 $ 0.7 $ 3.5 $ 0.8 Finance Lease Liabilities Current Portion Other Current Liabilities $ 3.9 $ — $ — $ 0.1 $ 5.0 $ 1.4 $ — $ 0.1 Long-Term Other Long-Term Liabilities 55.4 — 4.9 0.6 57.6 — 4.8 0.7 Total Finance Lease Liabilities $ 59.3 $ — $ 4.9 $ 0.7 $ 62.6 $ 1.4 $ 4.8 $ 0.8 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: As of December 31, 2021 2020 Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Weighted-Average Remaining Lease Term (Years): Operating Leases 13 7 18 7 10 3 19 8 Finance Leases 16 — 20 7 17 1 21 8 Weighted-Average Discount Rate (Percentage): Operating Leases 4.1 % 3.0 % 4.0 % 3.7 % 4.0 % 2.4 % 4.1 % 3.7 % Finance Leases 2.7 % — % 2.9 % 3.5 % 2.9 % 10.5 % 2.9 % 3.5 % (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2021 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 12.1 $ 0.3 $ 2.1 $ 0.1 Operating Cash Flows from Finance Leases 3.4 0.1 0.6 — Financing Cash Flows from Finance Leases 4.1 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.1 — 1.9 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.3 — — — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2020 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 10.9 $ 0.6 $ 1.8 $ 0.1 Operating Cash Flows from Finance Leases 1.7 0.3 0.6 — Financing Cash Flows from Finance Leases 2.8 1.6 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.6 0.1 0.2 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 0.7 — 0.3 — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 11.4 $ 0.4 $ 1.6 $ 0.1 Operating Cash Flows from Finance Leases 1.2 0.6 0.6 — Financing Cash Flows from Finance Leases 2.6 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.9 1.0 0.1 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.0 — — — In 2020, Eversource also acquired $14.7 million of right-of-use assets in exchange for the assumption of new operating lease liabilities and $54.2 million of right-of-use assets in exchange for the assumption of new finance lease liabilities as a result of the CMA asset acquisition. Future minimum lease payments, excluding variable costs, under long-term leases, as of December 31, 2021 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource NSTAR Electric PSNH Year Ending December 31, 2022 $ 11.1 $ 0.1 $ 2.1 $ 0.1 $ 6.0 $ 0.6 $ 0.1 2023 7.6 — 2.1 0.1 5.2 0.7 0.1 2024 6.1 — 2.1 — 5.3 0.7 0.1 2025 3.2 — 1.7 — 5.2 0.6 0.1 2026 2.5 — 1.7 — 4.7 0.6 0.1 Thereafter 27.8 — 25.3 0.1 56.0 12.4 0.3 Future lease payments 58.3 0.1 35.0 0.3 82.4 15.6 0.8 Less amount representing interest 11.1 — 10.7 — 23.1 10.7 0.1 Present value of future minimum lease payments $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 59.3 $ 4.9 $ 0.7

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2021
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 Fair Carrying Fair Carrying Fair As of December 31, 2021: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 166.3 $ 116.2 $ 122.3 $ 43.0 $ 44.0 $ — $ — Long-Term Debt 18,216.7 19,636.3 4,215.4 4,848.9 3,985.4 4,453.5 1,163.8 1,220.6 Rate Reduction Bonds 496.9 543.3 — — — — 496.9 543.3 As of December 31, 2020: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 169.1 $ 116.2 $ 123.4 $ 43.0 $ 45.7 $ — $ — Long-Term Debt 16,179.1 18,420.1 3,914.8 4,800.9 3,643.2 4,294.0 1,099.1 1,207.0 Rate Reduction Bonds 540.1 603.4 — — — — 540.1 603.4 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 1I, "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)	12 Months Ended
	Dec. 31, 2021
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 Year Ended December 31, 2021 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Qualified Unrealized Defined Total Qualified Unrealized Defined Total Balance as of January 1st $ (1.4) $ 1.1 $ (76.1) $ (76.4) $ (3.0) $ 0.7 $ (62.8) $ (65.1) OCI Before Reclassifications — (0.7) 24.1 23.4 — 0.4 (19.6) (19.2) Amounts Reclassified from AOCI 1.0 — 9.7 10.7 1.6 — 6.3 7.9 Net OCI 1.0 (0.7) 33.8 34.1 1.6 0.4 (13.3) (11.3) Balance as of December 31st $ (0.4) $ 0.4 $ (42.3) $ (42.3) $ (1.4) $ 1.1 $ (76.1) $ (76.4) 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. The related tax effects of the defined benefit plan OCI amounts before reclassifications recognized in AOCI were net deferred tax liabilities of $8.3 million in 2021 and deferred tax assets of $6.0 million and $4.4 million in 2020 and 2019, respectively. The following table sets forth the amounts reclassified from AOCI by component and the impacted line item on the statements of income: Amounts Reclassified from AOCI Eversource (Millions of Dollars) For the Years Ended December 31, Statements of Income 2021 2020 2019 Qualified Cash Flow Hedging Instruments $ (1.7) $ (2.5) $ (2.5) Interest Expense Tax Effect 0.7 0.9 1.1 Income Tax Expense Qualified Cash Flow Hedging Instruments, Net of Tax $ (1.0) $ (1.6) $ (1.4) Defined Benefit Plan Costs: Amortization of Actuarial Losses $ (13.1) $ (8.1) $ (5.7) Other Income, Net (1) Amortization of Prior Service Credit/(Cost) — (0.3) (1.8) Other Income, Net (1) Total Defined Benefit Plan Costs (13.1) (8.4) (7.5) Tax Effect 3.4 2.1 1.9 Income Tax Expense Defined Benefit Plan Costs, Net of Tax $ (9.7) $ (6.3) $ (5.6) Total Amounts Reclassified from AOCI, Net of Tax $ (10.7) $ (7.9) $ (7.0) (1) These amounts are included in the computation of net periodic Pension, SERP and PBOP costs. See Note 1M, "Summary of Significant Accounting Policies – Other Income, Net" and Note 11A, "Employee Benefits – Pension Benefits and Postretirement Benefits Other Than Pension," for further information. As of December 31, 2021, it is estimated that a pre-tax amount of $0.1 million ($0.1 million for NSTAR Electric) will be reclassified from AOCI as a decrease to Net Income over the next 12 months as a result of the amortization of the interest rate swap agreements which have been settled.

DIVIDEND RESTRICTIONS

DIVIDEND RESTRICTIONS	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
DIVIDEND RESTRICTIONS	DIVIDEND RESTRICTIONS Eversource parent's ability to pay dividends may be affected by certain state statutes, the ability of its subsidiaries to pay common dividends and the leverage restriction tied to its consolidated total debt to total capitalization ratio requirement in its revolving credit agreements. Pursuant to the joint revolving credit agreement of Eversource, CL&P, PSNH, NSTAR Gas, Yankee Gas, EGMA and Aquarion Water Company of Connecticut, and to the NSTAR Electric revolving credit agreement, each company is required to maintain consolidated total indebtedness to total capitalization ratio of no greater than 65 percent at the end of each fiscal quarter. As of December 31, 2021, all companies were in compliance with such covenant and in compliance with all such provisions of the revolving credit agreements that may restrict the payment of dividends as of December 31, 2021. The Retained Earnings balances subject to dividend restrictions were $5.01 billion for Eversource, $2.23 billion for CL&P, $2.72 billion for NSTAR Electric and $504.6 million for PSNH as of December 31, 2021.

COMMON SHARES

COMMON SHARES	12 Months Ended
	Dec. 31, 2021
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 Par Value Authorized as of December 31, 2021 and 2020 Issued as of December 31, 2021 2020 Eversource $ 5 380,000,000 357,818,402 357,818,402 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 Issuances and 2019 Forward Sale Agreement: On June 15, 2020, Eversource completed an equity offering of 6,000,000 common shares at a price per share of $86.26. Eversource used the net proceeds of this offering to fund a portion of the purchase of the assets of CMA that closed on October 9, 2020. The issuance of these common shares resulted in proceeds of $509.2 million, net of issuance costs. In June 2019, Eversource completed an equity offering 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. Under the forward sale agreement, 11,960,000 common shares were borrowed from third parties and sold by the underwriters. The forward sale agreement allowed 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 was subject to adjustment daily based on a floating interest rate factor and would decrease in respect of certain fixed amounts specified in the agreement, such as dividends. Eversource issued 6,000,000 common shares under the forward sale agreement in December 2019. On March 23, 2020, Eversource physically settled a portion of the forward sale agreement by delivering 1,500,000 common shares in exchange for net proceeds of $105.7 million. Subsequently, on March 26, 2020, Eversource physically settled the remaining portion of the forward sale agreement by delivering 4,460,000 common shares in exchange for net proceeds of $314.1 million. The forward sale price used to determine the cash proceeds received by Eversource was calculated based on the initial forward sale price, as adjusted in accordance with the forward sale agreement. The March and June 2020 common share issuances of 5,960,000 and 6,000,000, respectively, resulted in total proceeds of $929.0 million, net of issuance costs. The June and December 2019 common share issuances of 5,980,000 and 6,000,000, respectively, resulted in total proceeds of $852.3 million. These issuances were reflected in shareholders’ equity and as financing activities on the statements of cash flows. Issuances of shares under the forward sale agreement were classified as equity transactions. Accordingly, no amounts relating to the forward sale agreement were recorded in the financial statements until settlements took place. Prior to any settlements, the only impact of the forward sale agreement to the financial statements was the inclusion of incremental shares within the calculation of diluted EPS using the treasury stock method. See Note 21, "Earnings Per Share," to the financial statements for information on the forward sale agreement’s impact on the calculation of diluted EPS. Eversource used the net proceeds received from the direct issuance of common shares and the net proceeds received from settlement of the forward sale agreement to repay short-term debt under the commercial paper program, to partially fund the purchase of the assets of CMA, to fund capital spending and clean energy initiatives, and for general corporate purposes. Treasury Shares: As of December 31, 2021 and 2020, there were 13,415,206 and 14,864,379 Eversource common shares held as treasury shares, respectively. As of December 31, 2021 and 2020, there were 344,403,196 and 342,954,023 Eversource common shares outstanding, respectively. On December 1, 2021, Aquarion acquired New England Service Company (NESC), pursuant to a definitive agreement entered into on April 8, 2021. The acquisition was structured as a stock-for-stock merger and Eversource issued 462,517 treasury shares at closing for a purchase price of $38.1 million. Eversource issues 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.

PREFERRED STOCK NOT SUBJECT TO

PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION	PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION The CL&P and NSTAR Electric preferred stock is not subject to mandatory redemption and is presented as a noncontrolling interest of a subsidiary in Eversource's financial statements. Details of preferred stock not subject to mandatory redemption are as follows (in millions, except in redemption price and shares): Redemption Price Shares Outstanding as of December 31, As of December 31, Series 2021 2020 2021 2020 CL&P $1.90 Series of 1947 $ 52.50 163,912 163,912 $ 8.2 $ 8.2 $2.00 Series of 1947 $ 54.00 336,088 336,088 16.8 16.8 $2.04 Series of 1949 $ 52.00 100,000 100,000 5.0 5.0 $2.20 Series of 1949 $ 52.50 200,000 200,000 10.0 10.0 3.90% Series of 1949 $ 50.50 160,000 160,000 8.0 8.0 $2.06 Series E of 1954 $ 51.00 200,000 200,000 10.0 10.0 $2.09 Series F of 1955 $ 51.00 100,000 100,000 5.0 5.0 4.50% Series of 1956 $ 50.75 104,000 104,000 5.2 5.2 4.96% Series of 1958 $ 50.50 100,000 100,000 5.0 5.0 4.50% Series of 1963 $ 50.50 160,000 160,000 8.0 8.0 5.28% Series of 1967 $ 51.43 200,000 200,000 10.0 10.0 $3.24 Series G of 1968 $ 51.84 300,000 300,000 15.0 15.0 6.56% Series of 1968 $ 51.44 200,000 200,000 10.0 10.0 Total CL&P 2,324,000 2,324,000 $ 116.2 $ 116.2 NSTAR Electric 4.25% Series of 1956 $ 103.625 180,000 180,000 $ 18.0 $ 18.0 4.78% Series of 1958 $ 102.80 250,000 250,000 25.0 25.0 Total NSTAR Electric 430,000 430,000 $ 43.0 $ 43.0 Fair Value Adjustment due to Merger with NSTAR (3.6) (3.6) Other 6.00% Series of 1958 $ 100.00 23 23 $ — $ — Total Eversource - Noncontrolling Interest - Preferred Stock of Subsidiaries $ 155.6 $ 155.6

COMMON SHAREHOLDERS' EQUITY AND

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	12 Months Ended
	Dec. 31, 2021
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 Par Value Authorized as of December 31, 2021 and 2020 Issued as of December 31, 2021 2020 Eversource $ 5 380,000,000 357,818,402 357,818,402 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 Issuances and 2019 Forward Sale Agreement: On June 15, 2020, Eversource completed an equity offering of 6,000,000 common shares at a price per share of $86.26. Eversource used the net proceeds of this offering to fund a portion of the purchase of the assets of CMA that closed on October 9, 2020. The issuance of these common shares resulted in proceeds of $509.2 million, net of issuance costs. In June 2019, Eversource completed an equity offering 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. Under the forward sale agreement, 11,960,000 common shares were borrowed from third parties and sold by the underwriters. The forward sale agreement allowed 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 was subject to adjustment daily based on a floating interest rate factor and would decrease in respect of certain fixed amounts specified in the agreement, such as dividends. Eversource issued 6,000,000 common shares under the forward sale agreement in December 2019. On March 23, 2020, Eversource physically settled a portion of the forward sale agreement by delivering 1,500,000 common shares in exchange for net proceeds of $105.7 million. Subsequently, on March 26, 2020, Eversource physically settled the remaining portion of the forward sale agreement by delivering 4,460,000 common shares in exchange for net proceeds of $314.1 million. The forward sale price used to determine the cash proceeds received by Eversource was calculated based on the initial forward sale price, as adjusted in accordance with the forward sale agreement. The March and June 2020 common share issuances of 5,960,000 and 6,000,000, respectively, resulted in total proceeds of $929.0 million, net of issuance costs. The June and December 2019 common share issuances of 5,980,000 and 6,000,000, respectively, resulted in total proceeds of $852.3 million. These issuances were reflected in shareholders’ equity and as financing activities on the statements of cash flows. Issuances of shares under the forward sale agreement were classified as equity transactions. Accordingly, no amounts relating to the forward sale agreement were recorded in the financial statements until settlements took place. Prior to any settlements, the only impact of the forward sale agreement to the financial statements was the inclusion of incremental shares within the calculation of diluted EPS using the treasury stock method. See Note 21, "Earnings Per Share," to the financial statements for information on the forward sale agreement’s impact on the calculation of diluted EPS. Eversource used the net proceeds received from the direct issuance of common shares and the net proceeds received from settlement of the forward sale agreement to repay short-term debt under the commercial paper program, to partially fund the purchase of the assets of CMA, to fund capital spending and clean energy initiatives, and for general corporate purposes. Treasury Shares: As of December 31, 2021 and 2020, there were 13,415,206 and 14,864,379 Eversource common shares held as treasury shares, respectively. As of December 31, 2021 and 2020, there were 344,403,196 and 342,954,023 Eversource common shares outstanding, respectively. On December 1, 2021, Aquarion acquired New England Service Company (NESC), pursuant to a definitive agreement entered into on April 8, 2021. The acquisition was structured as a stock-for-stock merger and Eversource issued 462,517 treasury shares at closing for a purchase price of $38.1 million. Eversource issues 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.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2021
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 18, "Common Shares," earnings per share dilution related to the forward sale agreement was 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 price 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. Eversource physically settled all remaining shares under the forward sale agreement as of March 26, 2020. For the years ended December 31, 2021 and 2019, there were no antidilutive share awards excluded from the computation. For the year ended December 31, 2020, 39,560 antidilutive share awards were excluded from the EPS computation, as their impact would have been antidilutive . Antidilutive shares pertained to a purchase option extended to underwriters in connection with Eversource's common share issuance on June 15, 2020. See Note 18, "Common Shares," for further information. The following table sets forth the components of basic and diluted EPS: Eversource (Millions of Dollars, except share information) For the Years Ended December 31, 2021 2020 2019 Net Income Attributable to Common Shareholders $ 1,220.5 $ 1,205.2 $ 909.1 Weighted Average Common Shares Outstanding: Basic 343,972,926 338,836,147 321,416,086 Dilutive Effect of: Share-Based Compensation Awards and Other 658,130 738,994 762,215 Equity Forward Sale Agreement — 271,921 763,335 Total Dilutive Effect 658,130 1,010,915 1,525,550 Diluted 344,631,056 339,847,062 322,941,636 Basic EPS $ 3.55 $ 3.56 $ 2.83 Diluted EPS $ 3.54 $ 3.55 $ 2.81

REVENUES

REVENUES	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
REVENUES	REVENUES Revenue is recognized when promised goods or services (referred to as performance obligations) are transferred to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. A five-step model is used for recognizing and measuring revenue from contracts with customers, which includes identifying the contract with the customer, identifying the performance obligations promised within the contract, determining the transaction price (the amount of consideration to which the company expects to be entitled), allocating the transaction price to the performance obligations and recognizing revenue when (or as) the performance obligation is satisfied. The following tables present operating revenues disaggregated by revenue source: For the Year Ended December 31, 2021 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,989.8 $ 1,000.3 $ — $ 133.5 $ — $ — $ 5,123.6 Commercial 2,486.1 497.6 — 62.8 — (5.1) 3,041.4 Industrial 345.3 167.2 — 4.3 — (17.1) 499.7 Total Retail Tariff Sales Revenues 6,821.2 1,665.1 — 200.6 — (22.2) 8,664.7 Wholesale Transmission Revenues — — 1,751.3 — 86.6 (1,384.7) 453.2 Wholesale Market Sales Revenues 575.8 82.1 — 3.9 — — 661.8 Other Revenues from Contracts with Customers 78.1 5.1 13.6 7.5 1,267.4 (1,257.7) 114.0 Reserve for Revenues Subject to Refund (71.1) — (5.0) (2.6) — — (78.7) Total Revenues from Contracts with Customers 7,404.0 1,752.3 1,759.9 209.4 1,354.0 (2,664.6) 9,815.0 Alternative Revenue Programs 14.7 37.0 (126.1) 1.5 — 114.6 41.7 Other Revenues 4.9 0.3 0.8 0.4 — — 6.4 Total Operating Revenues $ 7,423.6 $ 1,789.6 $ 1,634.6 $ 211.3 $ 1,354.0 $ (2,550.0) $ 9,863.1 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,951.5 $ 644.9 $ — $ 145.1 $ — $ — $ 4,741.5 Commercial 2,353.4 361.9 — 62.4 — (4.8) 2,772.9 Industrial 327.1 107.4 — 4.8 — (13.7) 425.6 Total Retail Tariff Sales Revenues 6,632.0 1,114.2 — 212.3 — (18.5) 7,940.0 Wholesale Transmission Revenues — — 1,557.3 — 74.2 (1,290.6) 340.9 Wholesale Market Sales Revenues 327.3 43.0 — 3.8 — — 374.1 Other Revenues from Contracts with Customers 79.3 5.7 13.3 3.5 1,161.7 (1,152.0) 111.5 Total Revenues from Contracts with Customers 7,038.6 1,162.9 1,570.6 219.6 1,235.9 (2,461.1) 8,766.5 Alternative Revenue Programs 88.1 44.7 (35.2) (4.7) — 37.1 130.0 Other Revenues 5.6 1.1 0.7 0.5 — — 7.9 Total Operating Revenues $ 7,132.3 $ 1,208.7 $ 1,536.1 $ 215.4 $ 1,235.9 $ (2,424.0) $ 8,904.4 For the Year Ended December 31, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,723.7 $ 555.1 $ — $ 132.3 $ — $ — $ 4,411.1 Commercial 2,584.8 347.6 — 63.9 — (4.3) 2,992.0 Industrial 331.8 96.9 — 4.5 — (11.6) 421.6 Total Retail Tariff Sales Revenues 6,640.3 999.6 — 200.7 — (15.9) 7,824.7 Wholesale Transmission Revenues — — 1,293.3 — 61.3 (1,085.2) 269.4 Wholesale Market Sales Revenues 215.7 55.4 — 4.1 — — 275.2 Other Revenues from Contracts with Customers 56.1 9.0 13.2 4.2 967.2 (969.0) 80.7 Total Revenues from Contracts with Customers 6,912.1 1,064.0 1,306.5 209.0 1,028.5 (2,070.1) 8,450.0 Alternative Revenue Programs 45.9 (4.9) 81.8 4.6 — (74.2) 53.2 Other Revenues 18.5 3.1 0.7 1.0 — — 23.3 Total Operating Revenues $ 6,976.5 $ 1,062.2 $ 1,389.0 $ 214.6 $ 1,028.5 $ (2,144.3) $ 8,526.5 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,994.2 $ 1,375.8 $ 619.8 $ 2,011.1 $ 1,365.8 $ 574.6 $ 1,837.1 $ 1,322.1 $ 564.5 Commercial 890.6 1,265.0 332.2 878.3 1,176.8 299.9 922.9 1,349.4 314.6 Industrial 131.4 119.1 94.8 137.5 106.4 83.2 138.3 115.8 77.7 Total Retail Tariff Sales Revenues 3,016.2 2,759.9 1,046.8 3,026.9 2,649.0 957.7 2,898.3 2,787.3 956.8 Wholesale Transmission Revenues 863.3 616.3 271.7 754.8 576.5 226.0 587.1 517.3 188.9 Wholesale Market Sales Revenues 408.8 109.2 57.8 230.1 58.4 38.8 105.1 73.1 37.5 Other Revenues from Contracts 26.7 56.2 11.3 32.9 43.6 14.2 36.4 18.7 15.6 (Reserve for)/Amortization of Revenues (76.1) — — — — 4.6 — — 1.3 Total Revenues from Contracts 4,238.9 3,541.6 1,387.6 4,044.7 3,327.5 1,241.3 3,626.9 3,396.4 1,200.1 Alternative Revenue Programs (78.9) (15.1) (17.4) (4.2) 54.5 2.6 77.5 41.6 8.6 Other Revenues 0.4 3.4 1.9 2.2 3.5 0.6 10.3 7.0 1.9 Eliminations (523.0) (473.5) (194.9) (495.2) (444.4) (165.4) (482.1) (400.4) (144.7) Total Operating Revenues $ 3,637.4 $ 3,056.4 $ 1,177.2 $ 3,547.5 $ 2,941.1 $ 1,079.1 $ 3,232.6 $ 3,044.6 $ 1,065.9 Retail Tariff Sales: Regulated utilities provide products and services to their regulated customers under rates, pricing, payment terms and conditions of service, regulated by each state regulatory agency. The arrangement whereby a utility provides commodity service to a customer for a price approved by the respective state regulatory commission is referred to as a tariff sale contract, and the tariff governs all aspects of the provision of regulated services by utilities. The majority of revenue for Eversource, CL&P, NSTAR Electric and PSNH is derived from regulated retail tariff sales for the sale and distribution of electricity, natural gas and water to residential, commercial and industrial retail customers. The utility's performance obligation for the regulated tariff sales is to provide electricity, natural gas or water to the customer as demanded. The promise to provide the commodity represents a single performance obligation, as it is a promise to transfer a series of distinct goods or services that are substantially the same and that have the same pattern of transfer to the customer. Revenue is recognized over time as the customer simultaneously receives and consumes the benefits provided by the utility, and the utility satisfies its performance obligation. Revenue is recognized based on the output method as there is a directly observable output to the customer (electricity, natural gas or water units delivered to the customer and immediately consumed). Each Eversource utility is entitled to be compensated for performance completed to date (service taken by the customer) until service is terminated. In regulated tariff sales, the transaction prices are the rates approved by the respective state regulatory commissions. In general, rates can only be changed through formal proceedings with the state regulatory commissions. These rates are designed to recover the costs to provide service to customers and include a return on investment. Regulatory commission-approved tracking mechanisms are included in these rates and are also used to recover, on a fully-reconciling basis, certain costs, such as the procurement of energy supply, retail transmission charges, energy efficiency program costs, net metering for distributed generation, and restructuring and stranded costs. These tracking mechanisms result in rates being changed periodically to ensure recovery of actual costs incurred and the refund of any overcollection of costs. Customers may elect to purchase electricity from each Eversource electric utility or may contract separately with a competitive third party supplier. Revenue is not recorded for the sale of the electricity commodity to customers who have contracted separately with these suppliers, only the delivery to a customer, as the utility is acting as an agent on behalf of the third party supplier. Wholesale Transmission Revenues: The Eversource electric transmission-owning companies (CL&P, NSTAR Electric and PSNH) each own and maintain transmission facilities that are part of an interstate power transmission grid over which electricity is transmitted throughout New England. CL&P, NSTAR Electric and PSNH, as well as most other New England utilities, are parties to a series of agreements that provide for coordinated planning and operation of the region's transmission facilities and the rules by which they acquire transmission services. The Eversource electric transmission-owning companies have a combination of FERC-approved regional and local formula rates that work in tandem to recover all their transmission costs. These rates are part of the ISO-NE Tariff. Regional rates recover the costs of higher voltage transmission facilities that benefit the region and are collected from all New England transmission customers, including the Eversource distribution businesses. Eversource's local rates, under our FERC-approved tariff in effect in 2021, recover the companies' total transmission revenue requirements, less revenues received from regional rates and other sources, and are collected from Eversource's distribution businesses and other transmission customers. The distribution businesses of Eversource, in turn, recover the FERC approved charges from retail customers through annual tracking mechanisms, which are retail tariff sales. The utility's performance obligation for regulated wholesale transmission sales is to provide transmission services to the customer as demanded. The promise to provide transmission service represents a single performance obligation. The transaction prices are the transmission rate formulas as defined by the ISO-NE Tariff and are regulated and established by FERC. Wholesale transmission revenue is recognized over time as the performance obligation is completed, which occurs as transmission services are provided to customers. The revenue is recognized based on the output method. Each Eversource utility is entitled to be compensated for performance completed to date (e.g., use of the transmission system by the customer). Wholesale Market Sales Revenues: Wholesale market sales transactions include sales of energy and energy-related products into the ISO-NE wholesale electricity market, sales of natural gas to third party marketers, and also the sale of RECs to various counterparties. ISO-NE oversees the region's wholesale electricity market and administers the transactions and terms and conditions, including payment terms, which are established in the ISO-NE tariff, between the buyers and sellers in the market. Pricing is set by the wholesale market. The wholesale transactions in the ISO-NE market occur on a day-ahead basis or a real-time basis (daily) and are, therefore, short-term. Transactions are tracked and reported by ISO-NE net by the hour, which is the net hourly position of energy sales and purchases by each market participant. The performance obligation for ISO-NE energy transactions is defined to be the net by hour transaction. Revenue is recognized when the performance obligation for these energy sales transactions is satisfied, when the sale occurs and the energy is transferred to the customer. For sales of natural gas, transportation, and natural gas pipeline capacity to third party marketers, revenue is recognized when the performance obligation is satisfied at the point in time the sale occurs and the natural gas or related product is transferred to the marketer. RECs are sold to various counterparties, and revenue is recognized when the performance obligation is satisfied upon transfer of title to the customer through the New England Power Pool Generation Information System. Wholesale transactions also include the sale of CL&P’s, NSTAR Electric’s and PSNH’s transmission rights associated with their proportionate equity ownership share in the transmission lines of the Hydro-Québec system in Canada. Other Revenues from Contracts with Customers: Other revenues from contracts with customers primarily include property rentals that are not deemed leases. These revenues are generally recognized on a straight-line basis over time as the service is provided to the customer. Other revenues also include revenues from Eversource's service company, which is eliminated in consolidation. (Reserve for)/Amortization of Revenues Subject to Refund: A reserve is recorded as a reduction to revenues when future refunds to customers are deemed probable. The reserve is reversed as refunds are provided to customers. Revenues subject to refund primarily relate to a PURA-approved CL&P settlement agreement with the DEEP, OCC, AG and the Connecticut Industrial Energy Consumers, which resolved certain issues that arose in then-pending regulatory proceedings initiated by the PURA. CL&P recorded a reduction to Operating Revenues of $65 million on the 2021 income statement for a reserve for customer credits associated with the provisions of the settlement agreement. The customer credits were distributed based on customer sales over a two-month billing period from December 1, 2021 to January 31, 2022. Additionally, CL&P recorded a $28.4 million reserve in 2021 for a civil penalty for non-compliance with storm performance standards that is currently being credited to customers on electric bills beginning on September 1, 2021 over a one-year period. In total, the reserve for revenues subject to refund totaled $93.4 million and was recorded as a current regulatory liability on CL&P’s balance sheet and as a reduction to Operating Revenues for the year ended December 31, 2021. The balance reflected in the table above primarily represents the remaining reserve that has not yet been issued as customer credits as of December 31, 2021. See Note 13G, “Commitments and Contingencies - CL&P Regulatory Matters,” for further information. The Connecticut water business continues to record a regulatory liability and reduction to revenues to reflect the difference between the 35 percent federal corporate income tax rate included in base distribution rates charged to customers and the 21 percent federal corporate income tax rate currently effective. This reserve will continue until base distribution rates are updated to reflect the lower federal tax rate. Alternative Revenue Programs: In accordance with accounting guidance for rate-regulated operations, certain of Eversource's utilities' rate making mechanisms qualify as alternative revenue programs (ARPs) if they meet specified criteria, in which case revenues may be recognized prior to billing based on allowed levels of collection in rates. Eversource's utility companies recognize revenue and record a regulatory asset or liability once the condition or event allowing for the automatic adjustment of future rates occurs. ARP revenues include both the recognition of the deferral adjustment to ARP revenues, when the regulator-specified condition or event allowing for additional billing or refund has occurred, and an equal and offsetting reversal of the ARP deferral to revenues as those amounts are reflected in the price of service in subsequent periods. Eversource’s ARPs include the revenue decoupling mechanism, the annual reconciliation adjustment to transmission formula rates, and certain capital tracker mechanisms. Certain Eversource electric, natural gas and water companies, including CL&P and NSTAR Electric, have revenue decoupling mechanisms approved by a regulatory commission (decoupled companies). Decoupled companies’ distribution revenues are not directly based on sales volumes. The decoupled companies reconcile their annual base distribution rate recovery to pre-established levels of baseline distribution delivery service revenues, with any difference between the allowed level of distribution revenue and the actual amount realized adjusted through subsequent rates. The transmission formula rates provide for the annual reconciliation and recovery or refund of estimated costs to actual costs. The financial impacts of differences between actual and estimated costs are deferred for future recovery from, or refund to, transmission customers. This transmission deferral reconciles billed transmission revenues to the revenue requirement for our transmission businesses. Other Revenues: Other Revenues include certain fees charged to customers that are not considered revenue from contracts with customers. Other revenues also include lease revenues under lessor accounting guidance of $4.8 million ($0.8 million at CL&P and $3.1 million at NSTAR Electric), $4.3 million ($0.8 million at CL&P and $2.7 million at NSTAR Electric), $4.4 million, ($1.0 million at CL&P and $2.7 million at NSTAR Electric) for the years ended December 31, 2021, 2020 and 2019, respectively. Intercompany Eliminations: Intercompany eliminations are primarily related to the Eversource electric transmission revenues that are derived from ISO-NE regional transmission charges to the distribution businesses of CL&P, NSTAR Electric and PSNH that recover the costs of the wholesale transmission business, and revenues from Eversource's service company. Intercompany revenues and expenses between the Eversource wholesale transmission businesses and the Eversource distribution businesses and from Eversource's service company are eliminated in consolidation and included in "Eliminations" in the table above. Receivables: Receivables, Net on the balance sheet primarily includes trade receivables from retail customers and from customers related to wholesale transmission contracts, wholesale market sales, sales of RECs, and property rentals. In general, retail tariff customers and wholesale transmission customers are billed monthly and the payment terms are generally due and payable upon receipt of the bill. Unbilled Revenues: Unbilled Revenues on the balance sheet represent estimated amounts due from retail customers for electricity, natural gas or water delivered to customers but not yet billed. The utility company has satisfied its performance obligation and the customer has received and consumed the commodity as of the balance sheet date, and therefore, the utility company records revenue for those services in the period the services were provided. Only the passage of time is required before the company is entitled to payment for the satisfaction of the performance obligation. Payment from customers is due monthly as services are rendered and amounts are billed. Actual amounts billed to customers when meter readings become available may vary from the estimated amount. Unbilled revenues are recognized by allocating estimated unbilled sales volumes to the respective customer classes, and then applying an estimated rate by customer class to those sales volumes. Unbilled revenue estimates reflect seasonality, weather, customer usage patterns, customer rates in effect for customer classes, and the timing of customer billing. The companies that have a decoupling mechanism record a regulatory deferral to reflect the actual allowed amount of revenue associated with their respective decoupled distribution rate design.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2021
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 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) the results of other unregulated subsidiaries, which are not part of its core business, and 5) Eversource parent's equity ownership interests that are not consolidated, which primarily include the offshore wind business, a natural gas pipeline owned by Enbridge, Inc., and a renewable energy investment fund. In the ordinary course of business, Yankee Gas, NSTAR Gas and EGMA purchase natural gas transmission services from the Enbridge, Inc. natural gas pipeline project described above. These affiliate transaction costs total $77.7 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 Year Ended December 31, 2021 Eversource (Millions of Dollars) Electric Natural Gas Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 7,423.6 $ 1,789.6 $ 1,634.6 $ 211.3 $ 1,354.0 $ (2,550.0) $ 9,863.1 Depreciation and Amortization (737.8) (142.3) (300.3) (46.1) (113.1) 4.6 (1,335.0) Other Operating Expenses (5,970.0) (1,345.4) (496.2) (101.4) (1,170.4) 2,548.6 (6,534.8) Operating Income 715.8 301.9 838.1 63.8 70.5 3.2 1,993.3 Interest Expense (236.4) (58.6) (133.2) (32.0) (168.8) 46.6 (582.4) Interest Income 20.7 4.5 2.2 — 46.0 (47.8) 25.6 Other Income, Net 78.1 17.9 19.8 3.3 1,363.9 (1,347.3) 135.7 Income Tax (Expense)/Benefit (103.5) (60.9) (179.4) 1.7 (2.1) — (344.2) Net Income 474.7 204.8 547.5 36.8 1,309.5 (1,345.3) 1,228.0 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 470.1 $ 204.8 $ 544.6 $ 36.8 $ 1,309.5 $ (1,345.3) $ 1,220.5 Total Assets (as of) $ 25,411.2 $ 7,215.9 $ 12,377.8 $ 2,551.1 $ 22,674.7 $ (21,738.6) $ 48,492.1 Cash Flows Used for Investments in Plant $ 1,053.3 $ 721.1 $ 1,024.1 $ 137.2 $ 239.4 $ — $ 3,175.1 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Operating Revenues $ 7,132.3 $ 1,208.7 $ 1,536.1 $ 215.4 $ 1,235.9 $ (2,424.0) $ 8,904.4 Depreciation and Amortization (657.0) (87.9) (278.1) (44.2) (93.5) 1.6 (1,159.1) Other Operating Expenses (5,642.3) (913.8) (470.0) (86.6) (1,071.9) 2,428.0 (5,756.6) Operating Income 833.0 207.0 788.0 84.6 70.5 5.6 1,988.7 Interest Expense (216.0) (40.0) (126.8) (32.9) (161.0) 38.3 (538.4) Interest Income 3.2 0.9 4.7 — 37.8 (41.8) 4.8 Other Income, Net 58.0 3.1 23.3 2.0 1,382.9 (1,365.5) 103.8 Income Tax (Expense)/Benefit (129.6) (36.9) (183.8) (12.5) 16.6 — (346.2) Net Income 548.6 134.1 505.4 41.2 1,346.8 (1,363.4) 1,212.7 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 544.0 $ 134.1 $ 502.5 $ 41.2 $ 1,346.8 $ (1,363.4) $ 1,205.2 Total Assets (as of) $ 24,981.9 $ 6,450.5 $ 11,695.0 $ 2,375.2 $ 22,089.4 $ (21,492.4) $ 46,099.6 Cash Flows Used for Investments in Plant $ 1,079.0 $ 494.4 $ 1,004.6 $ 118.8 $ 246.2 $ — $ 2,943.0 For the Year Ended December 31, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Operating Revenues $ 6,976.5 $ 1,062.2 $ 1,389.0 $ 214.6 $ 1,028.5 $ (2,144.3) $ 8,526.5 Depreciation and Amortization (651.3) (68.3) (253.3) (46.9) (63.2) 2.3 (1,080.7) Impairment of Northern Pass Transmission — — (239.6) — — — (239.6) Other Operating Expenses (5,525.1) (830.8) (411.2) (101.0) (891.3) 2,143.7 (5,615.7) Operating Income 800.1 163.1 484.9 66.7 74.0 1.7 1,590.5 Interest Expense (206.4) (47.4) (125.7) (34.6) (170.3) 51.2 (533.2) Interest Income 13.3 0.1 1.5 — 48.7 (50.8) 12.8 Other Income, Net 46.8 1.6 29.2 0.4 945.3 (903.3) 120.0 Income Tax (Expense)/Benefit (135.9) (21.2) (130.5) 2.4 11.7 — (273.5) Net Income 517.9 96.2 259.4 34.9 909.4 (901.2) 916.6 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 513.3 $ 96.2 $ 256.5 $ 34.9 $ 909.4 $ (901.2) $ 909.1 Cash Flows Used for Investments in Plant $ 1,104.2 $ 460.2 $ 987.0 $ 118.0 $ 242.1 $ — $ 2,911.5

ACQUISITION OF ASSETS OF COLUMB

ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS	ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS On October 9, 2020, Eversource acquired certain assets and liabilities that comprised the NiSource Inc. (NiSource) natural gas distribution business in Massachusetts, which was previously doing business as CMA, pursuant to an asset purchase agreement (the Agreement) entered into on February 26, 2020 between Eversource and NiSource. The cash purchase price was $1.1 billion, plus a working capital amount of $68.6 million, as finalized in the first quarter of 2021. Eversource financed the acquisition through a combination of debt and equity issuances in a ratio that was consistent with its consolidated capital structure. The natural gas distribution assets acquired from CMA were assigned to EGMA, an indirect wholly-owned subsidiary of Eversource formed in 2020. The LNG assets acquired from CMA were assigned to Hopkinton LNG Corp. The transaction required approval by the DPU, the Maine Public Utilities Commission, the FERC, and the Federal Communications Commission, and review under the Hart-Scott-Rodino Act. The liabilities assumed by Eversource under the Agreement specifically excluded any liabilities (past or future) arising out of, or related to, the fires and explosions that occurred on September 13, 2018 in Lawrence, Andover and North Andover, Massachusetts related to the delivery of natural gas by CMA, including certain subsequent events, all as described and in the DPU's Order on Scope dated December 23, 2019 (D.P.U. 19-141) (the Greater Lawrence Incident or GLI). The liabilities assumed also excluded any further emergency events prior to the closing of the acquisition related to the restoration and reconstruction with respect to the GLI, including any losses arising out of, or related to, any litigation, demand, cause of action, claim, suit, investigation, proceeding, indemnification agreements or rights. Eversource did not assume any of CMA's or NiSource Inc.'s third party debt obligations or notes payable. On October 7, 2020, the DPU approved a rate settlement agreement with Eversource, EGMA, NiSource, Bay State, the Massachusetts Attorney General's Office, the DOER and the Low-Income Weatherization and Fuel Assistance Program Network, which requested approval of the February 26, 2020 Agreement, as well as a rate stabilization plan, among other items. Purchase Price Allocation : The allocation of the total purchase price to the estimated fair values of the assets acquired and liabilities assumed has been determined based on the accounting guidance for fair value measurements, which defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The final purchase price allocation reflects measurement period adjustments recorded in 2021 to reduce the fair values of certain regulatory and plant assets and certain liabilities acquired, resulting in a corresponding increase to Goodwill, based on new information received during the measurement period. The allocation of the cash purchase price as of October 9, 2020 is as follows: (Millions of Dollars) Current Assets $ 138 Restricted Cash 57 PP&E 1,182 Goodwill 52 Other Noncurrent Assets, excluding Goodwill 131 Other Current Liabilities (81) Other Noncurrent Liabilities (310) Cash Purchase Price $ 1,169 The fair values of CMA's assets and liabilities were determined based on significant estimates and assumptions, including Level 3 inputs, that are judgmental in nature. The allocation of the total purchase price includes adjustments to reflect plant that will not earn a return and to reduce rate base to the allowed $995 million as specified in the rate settlement agreement. Eversource also recorded a $6.7 million liability for the future refund to customers for CMA's overcollection of the lower income tax rate beginning in 2018. The excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed was recognized as goodwill. The goodwill reflects the value paid by Eversource primarily for expanding its natural gas infrastructure. The goodwill resulting from the acquisition has been assigned to the Natural Gas Distribution reporting unit. Under the terms of the rate settlement agreement, a portion of the proceeds of the sale due to NiSource was withheld and used to establish an Energy Relief Fund comprised of two components, an Arrearage Forgiveness Fund and a fund which is restricted for energy efficiency and clean energy measures in the Merrimack Valley. As a result, Eversource funded restricted cash accounts and established a liability totaling $56.8 million on the acquisition date. By December 31, 2020, $15.4 million of the Arrearage Forgiveness Fund was credited back to customers and the remainder was paid back to NiSource. The purchase price included in investing cash outflows on the statement of cash flows of $1.11 billion reflects the payment to NiSource, excluding the restricted cash funds. Pro Forma Financial Information: The following unaudited pro forma financial information reflects the pro forma combined results of operations of Eversource and the CMA business acquired and reflects the amortization of purchase price adjustments assuming the acquisition had taken place on January 1, 2019. The unaudited pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Eversource. Pro forma net income excludes the impact of assets and liabilities not assumed by Eversource, such as amounts directly associated with the GLI incident, and non-recurring costs associated with the transaction. For the Years Ended December 31, (Pro forma amounts in millions, except share amounts) 2020 2019 Operating Revenues $ 9,273 $ 9,103 Net Income Attributable to Common Shareholders 1,265 909 Basic EPS 3.73 2.83 Diluted EPS 3.72 2.82 Revenues and Net Income: The impact of CMA on Eversource's accompanying consolidated statement of income included operating revenues of $154.8 million and net income attributable to common shareholders of $13.9 million for the year ended December 31, 2020.

GOODWILL

GOODWILL	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL In a business combination, the excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed is recognized as goodwill. Goodwill is evaluated for impairment at least annually and more frequently if indicators of impairment arise. In accordance with the accounting standards, if the fair value of a reporting unit is less than its carrying value (including goodwill), the goodwill is tested for impairment. Goodwill is not subject to amortization, however is subject to a fair value based assessment for impairment at least annually and whenever facts or circumstances indicate that there may be an impairment. A resulting write-down, if any, would be charged to Operating Expenses. Eversource's reporting units for the purpose of testing goodwill are Electric Distribution, Electric Transmission, Natural Gas Distribution and Water Distribution. These reporting units are consistent with the operating segments underlying the reportable segments identified in Note 23, "Segment Information," to the financial statements. Eversource completed the acquisition of NESC on December 1, 2021, resulting in the addition of $21.7 million of goodwill, all of which was allocated to the Water Distribution reporting unit. Eversource completed the CMA asset acquisition on October 9, 2020, resulting in the addition of $51.9 million of goodwill, which included measurement period adjustments in 2021 resulting in an additional $9.6 million of goodwill. The goodwill was allocated to the Natural Gas Distribution reporting unit. On July 31, 2020, Eversource sold its water system and treatment plant that supplies water to the towns of Hingham, Hull and North Cohasset to the town of Hingham, Massachusetts, resulting in a reduction to goodwill of $23.6 million. This goodwill was previously reflected in the Water Distribution reporting unit. In assessing goodwill for impairment, an entity is permitted to first assess qualitatively whether it is more likely than not that goodwill impairment exists as of the annual impairment test date. A quantitative impairment test is required only if it is concluded that it is more likely than not that a reporting unit’s fair value is less than it’s carrying amount. The annual goodwill assessment included a qualitative evaluation of multiple factors that impact the fair value of the reporting units, including general, macroeconomic and market conditions, and entity-specific assumptions that affect the future cash flows of the reporting units. Key considerations include discount rates, utility sector market performance and merger transaction multiples, the Company's share price and credit ratings, analyst reports, financial performance, cost and risk factors, internal estimates and projections of future cash flows and net income, long-term strategy, the timing and outcome of rate cases, and recent regulatory and legislative proceedings. Eversource completed its annual goodwill impairment test for the Electric Distribution, Electric Transmission, Natural Gas Distribution and Water Distribution reporting units as of October 1, 2021 and determined that no impairment existed. There were no events subsequent to October 1, 2021 that indicated impairment of goodwill. The following table presents goodwill by reportable segment: (Millions of Dollars) Electric Electric Natural Gas Water Distribution Total Balance as of January 1, 2020 $ 2,544 $ 577 $ 399 $ 907 $ 4,427 Acquisition of CMA Assets — — 42 — 42 Sale of Hingham water system — — — (23) (23) Balance as of December 31, 2020 $ 2,544 $ 577 $ 441 $ 884 $ 4,446 CMA Measurement Period Adjustments — — 10 — 10 Acquisition of NESC — — — 21 21 Balance as of December 31, 2021 $ 2,544 $ 577 $ 451 $ 905 $ 4,477

SCHEDULE I - FINANCIAL INFORMAT

SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT	12 Months Ended
	Dec. 31, 2021
Condensed Financial Information Disclosure [Abstract]
SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT	SCHEDULE I EVERSOURCE ENERGY (PARENT) FINANCIAL INFORMATION OF REGISTRANT BALANCE SHEETS AS OF DECEMBER 31, 2021 AND 2020 (Thousands of Dollars) 2021 2020 ASSETS Current Assets: Cash $ 175 $ 434 Accounts Receivable from Subsidiaries 43,403 39,645 Notes Receivable from Subsidiaries 1,245,900 996,300 Prepayments and Other Current Assets 11,974 19,043 Total Current Assets 1,301,452 1,055,422 Deferred Debits and Other Assets: Investments in Subsidiary Companies, at Equity 16,108,190 15,483,263 Notes Receivable from Subsidiaries 1,001,000 1,110,400 Accumulated Deferred Income Taxes 17,409 33,469 Goodwill 3,852,524 3,231,811 Other Long-Term Assets 101,710 90,735 Total Deferred Debits and Other Assets 21,080,833 19,949,678 Total Assets $ 22,382,285 $ 21,005,100 LIABILITIES AND CAPITALIZATION Current Liabilities: Notes Payable $ 1,342,950 $ 1,054,325 Long-Term Debt - Current Portion 767,681 473,933 Accounts Payable to Subsidiaries 37,609 18,424 Other Current Liabilities 87,745 103,477 Total Current Liabilities 2,235,985 1,650,159 Deferred Credits and Other Liabilities 150,616 163,053 Long-Term Debt 5,395,840 5,128,322 Common Shareholders' Equity: Common Shares 1,789,092 1,789,092 Capital Surplus, Paid in 8,098,514 8,015,663 Retained Earnings 5,005,391 4,613,201 Accumulated Other Comprehensive Loss (42,275) (76,411) Treasury Stock (250,878) (277,979) Common Shareholders' Equity 14,599,844 14,063,566 Total Liabilities and Capitalization $ 22,382,285 $ 21,005,100 See the Combined Notes to Financial Statements in this Annual Report on Form 10-K for a description of significant accounting matters related to Eversource parent, including Eversource common shares information as described in Note 18, "Common Shares," material obligations and guarantees as described in Note 13, "Commitments and Contingencies," and debt agreements as described in Note 8, "Short-Term Debt," and Note 9, "Long-Term Debt." SCHEDULE I EVERSOURCE ENERGY (PARENT) FINANCIAL INFORMATION OF REGISTRANT STATEMENTS OF INCOME FOR THE YEARS ENDED DECEMBER 31, 2021, 2020 AND 2019 (Thousands of Dollars, Except Share Information) 2021 2020 2019 Operating Revenues $ — $ — $ — Operating Expenses: Other 43,048 28,645 50,100 Operating Loss (43,048) (28,645) (50,100) Interest Expense 163,613 160,887 163,937 Other Income, Net: Equity in Earnings of Subsidiaries 1,345,199 1,309,630 1,001,526 Other, Net 47,802 38,546 68,137 Other Income, Net 1,393,001 1,348,176 1,069,663 Income Before Income Tax Benefit 1,186,340 1,158,644 855,626 Income Tax Benefit (34,187) (46,523) (53,427) Net Income $ 1,220,527 $ 1,205,167 $ 909,053 Basic Earnings per Common Share $ 3.55 $ 3.56 $ 2.83 Diluted Earnings per Common Share $ 3.54 $ 3.55 $ 2.81 Weighted Average Common Shares Outstanding: Basic 343,972,926 338,836,147 321,416,086 Diluted 344,631,056 339,847,062 322,941,636 STATEMENTS OF COMPREHENSIVE INCOME 2021 2020 2019 Net Income $ 1,220,527 $ 1,205,167 $ 909,053 Other Comprehensive Income/(Loss), Net of Tax: Qualified Cash Flow Hedging Instruments 972 1,596 1,393 Changes in Unrealized (Losses)/Gains on Marketable Securities (671) 342 1,166 Change in Funded Status of Pension, SERP and PBOP Benefit Plans 33,835 (13,290) (7,618) Other Comprehensive Income/(Loss), Net of Tax 34,136 (11,352) (5,059) Comprehensive Income $ 1,254,663 $ 1,193,815 $ 903,994 See the Combined Notes to Financial Statements in this Annual Report on Form 10-K for a description of significant accounting matters related to Eversource parent, including Eversource common shares information as described in Note 18, "Common Shares," material obligations and guarantees as described in Note 13, "Commitments and Contingencies," and debt agreements as described in Note 8, "Short-Term Debt," and Note 9, "Long-Term Debt." SCHEDULE I EVERSOURCE ENERGY (PARENT) FINANCIAL INFORMATION OF REGISTRANT STATEMENTS OF CASH FLOWS FOR THE YEARS ENDED DECEMBER 31, 2021, 2020 and 2019 (Thousands of Dollars) 2021 2020 2019 Operating Activities: Net Income $ 1,220,527 $ 1,205,167 $ 909,053 Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities: Equity in Earnings of Subsidiaries (1,345,199) (1,309,630) (1,001,526) Cash Dividends Received from Subsidiaries 1,037,100 485,800 883,000 Deferred Income Taxes 20,293 (4,667) 13,382 Other 36,910 39,940 19,584 Changes in Current Assets and Liabilities: Accounts Receivables from Subsidiaries (3,758) (14,575) 7,105 Taxes Receivable/Accrued, Net (19,455) 35,300 (605) Accounts Payable to Subsidiaries 19,185 14,091 (4,099) Other Current Assets and Liabilities, Net 8,144 21,284 (2,503) Net Cash Flows Provided by Operating Activities 973,747 472,710 823,391 Investing Activities: Capital Contributions to Subsidiaries (1,033,000) (1,899,340) (1,039,000) Return of Capital from Subsidiaries 178,800 80,000 — Increase in Notes Receivable from Subsidiaries (140,200) (264,300) (218,100) Other Investing Activities (3,196) (367) (1,799) Net Cash Flows Used in Investing Activities (997,596) (2,084,007) (1,258,899) Financing Activities: Issuance of Common Shares, Net of Issuance Costs — 928,992 852,254 Cash Dividends on Common Shares (805,439) (744,665) (663,239) Issuance of Long-Term Debt 1,000,000 1,550,000 — Retirement of Long-Term Debt (450,000) — (350,000) Increase/(Decrease) in Notes Payable 288,625 (170,545) 593,370 Other Financing Activities (9,545) 46,480 4,001 Net Cash Flows Provided by Financing Activities 23,641 1,610,262 436,386 Net (Decrease)/Increase in Cash and Restricted Cash (208) (1,035) 878 Cash - Beginning of Year 434 1,469 591 Cash and Restricted Cash - End of Year $ 226 $ 434 $ 1,469 Supplemental Cash Flow Information: Cash Paid/(Received) During the Year for: Interest $ 164,568 $ 140,694 $ 161,323 Income Taxes $ (51,277) $ (43,158) $ (63,277) See the Combined Notes to Financial Statements in this Annual Report on Form 10-K for a description of significant accounting matters related to Eversource parent, including Eversource common shares information as described in Note 18, "Common Shares," material obligations and guarantees as described in Note 13, "Commitments and Contingencies," and debt agreements as described in Note 8, "Short-Term Debt," and Note 9, "Long-Term Debt."

SCHEDULE II - VALUATION AND QUA

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	SCHEDULE II EVERSOURCE ENERGY AND SUBSIDIARIES VALUATION AND QUALIFYING ACCOUNTS AND RESERVES FOR THE YEARS ENDED DECEMBER 31, 2021, 2020 AND 2019 (Thousands of Dollars) Column A Column B Column C Column D Column E Additions (1) (2) Description: Balance as of Beginning of Year Charged to Costs and Expenses Charged to Other Deductions -Describe (b) Balance as of End of Year Eversource : Reserves Deducted from Assets - Reserves for Uncollectible Accounts: 2021 $ 358,851 $ 60,886 $ 110,572 $ 112,903 $ 417,406 2020 224,821 53,461 145,005 64,436 358,851 2019 212,723 63,446 57,223 108,571 224,821 CL&P: Reserves Deducted from Assets - Reserves for Uncollectible Accounts: 2021 $ 157,447 $ 13,495 $ 57,779 $ 47,402 $ 181,319 2020 97,348 12,882 71,223 24,006 157,447 2019 88,034 15,947 38,935 45,568 97,348 NSTAR Electric: Reserves Deducted from Assets - Reserves for Uncollectible Accounts: 2021 $ 91,583 $ 16,649 $ 20,064 $ 31,291 $ 97,005 2020 75,406 15,293 23,424 22,540 91,583 2019 74,516 25,079 12,556 36,745 75,406 PSNH : Reserves Deducted from Assets - Reserves for Uncollectible Accounts: 2021 $ 17,157 $ 13,113 $ 3,135 $ 9,074 $ 24,331 2020 10,497 5,164 7,692 6,196 17,157 2019 11,065 6,726 872 8,166 10,497 (a) Amounts relate to uncollectible accounts receivables reserved for that are not charged to bad debt expense. CL&P, NSTAR Electric, NSTAR Gas, EGMA and Yankee Gas are allowed to recover in rates, amounts associated with certain uncollectible hardship accounts receivable. CL&P, NSTAR Electric, PSNH, NSTAR Gas and EGMA are also allowed to recover uncollectible energy supply costs through regulatory tracking mechanisms. Amounts in this column in 2020 also include a $24.2 million increase due to the CMA asset acquisition on October 9, 2020 at Eversource, and an increase due to the adoption of the credit loss accounting standard in 2020 of $23.8 million at Eversource, $22.2 million at CL&P, $0.3 million at PSNH, and a decrease of $1.3 million at NSTAR Electric.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The 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 consolidated financial statements of Eversource, NSTAR Electric and PSNH and the financial statements of CL&P are herein collectively referred to as the "financial statements." 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. Eversource consolidates the operations of CYAPC and YAEC, both of which are inactive regional nuclear power companies engaged in the long-term storage of their spent nuclear fuel. 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 holds several equity ownership interests that are not consolidated and are accounted for under the equity method. In accordance with accounting guidance on noncontrolling interests in consolidated financial statements, the Preferred Stock of CL&P and the Preferred Stock of NSTAR Electric, which are not owned by Eversource or its consolidated subsidiaries and are not subject to mandatory redemption, have been presented as noncontrolling interests in the financial statements of Eversource. The Preferred Stock of CL&P and the Preferred Stock of NSTAR Electric are considered to be temporary equity and have been classified between liabilities and permanent shareholders' equity on the balance sheets of Eversource, CL&P and NSTAR Electric due to a provision in the preferred stock agreements of both CL&P and NSTAR Electric that grant preferred stockholders the right to elect a majority of the CL&P and NSTAR Electric Boards of Directors, respectively, should certain conditions exist, such as if preferred dividends are in arrears for a specified amount of time. The Net Income reported in the statements of income and cash flows represents net income prior to apportionment to noncontrolling interests, which is represented by dividends on preferred stock of CL&P and NSTAR Electric. 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. COVID-19 has adversely affected customers, workers and the U.S. economy. We provide a critical service to our customers and have taken extensive measures to maintain its safety and reliability. We continue to address the impacts of the COVID-19 pandemic and how the related developments affect Eversource. We have not experienced significant impacts directly related to the pandemic that have materially affected our current operations, our workforce, or results of operations. The extent of the impact to us in the future will vary, and depend on the duration, scope and severity of the pandemic and the resulting impact on economic, health care and capital market conditions. The future impact will also depend on the outcome of future proceedings before our state regulatory commissions to recover our incremental costs associated with COVID-19, which include uncollectible customer receivable expenses. See Note 1F, "Summary of Significant Accounting Policies - Allowance for Uncollectible Accounts," for an evaluation of the allowance for doubtful accounts as of December 31, 2021 in light of the COVID-19 pandemic. As of December 31, 2021, we did not identify indicators or triggering events for impairments to our goodwill, long-lived assets, available-for-sale debt securities, or equity method investment carrying values.
Accounting Standards	Accounting Standards Accounting Standards Recently Adopted: On January 1, 2021, the Company adopted Accounting Standards Update (ASU) 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes , which eliminates certain exceptions to the general principles of current income tax guidance in ASC 740 and simplifies and improves consistency in application of that income tax guidance through clarifications of and amendments to ASC 740. The ASU did not have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric and PSNH.
Cash	CashCash includes cash on hand.  At the end of each reporting period, any overdraft amounts are reclassified from Cash to Accounts Payable on the balance sheets.
Provision for Uncollectible Accounts	Allowance for Uncollectible Accounts Receivables, Net on the balance sheets primarily includes trade receivables from retail customers and customers related to wholesale transmission contracts, wholesale market sales, sales of RECs, and property rentals. Receivables, Net also includes customer receivables for the purchase of electricity from a competitive third party supplier, the current portion of customer energy efficiency loans, property damage receivables and other miscellaneous receivables. There is no material concentration of receivables. Receivables are recorded at amortized cost, net of a credit loss provision (or allowance for uncollectible accounts). Receivables are presented net of expected credit losses at estimated net realizable value by maintaining an allowance for uncollectible accounts. The current expected credit loss (CECL) model, which was implemented on January 1, 2020 (ASU 2016-13) is applied to receivables for purposes of calculating the allowance for uncollectible accounts. This model is based on expected losses and results in the recognition of estimated expected credit losses, including uncollectible amounts for both billed and unbilled revenues, over the life of the receivable at the time a receivable is recorded. The allowance for uncollectible accounts is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. Factors in determining credit loss include historical collection, write-off experience, and management's assessment of collectability from customers, including current conditions, reasonable forecasts, and expectations of future collectability and collection efforts. Management continuously assesses the collectability of receivables and adjusts estimates based on actual experience and future expectations based on economic indicators, collection efforts and other factors. Management also monitors the aging analysis of receivables to determine if there are changes in the collections of accounts receivable. Receivable balances are written off against the allowance for uncollectible accounts when the customer accounts are no longer in service and these balances are deemed to be uncollectible. As of December 31, 2021, management evaluated the adequacy of the allowance for uncollectible accounts in light of the evolving COVID-19 pandemic. This evaluation included an analysis of collection and customer payment trends, economic conditions, delinquency statistics, aging-based quantitative assessments, the impact on residential customer bills because of energy usage and change in rates, flexible payment plans and financial hardship arrearage management programs being offered to customers, and COVID-19 developments, including any potential federal governmental pandemic relief programs and the expansion of unemployment benefit initiatives, which help to mitigate the potential for increasing customer account delinquencies. Additionally, management considered past economic declines and corresponding uncollectible reserves as part of the current assessment. This evaluation has shown that our operating companies have experienced an increase in aged receivables and lower cash collections from customers because of the length of the moratorium on disconnections in Connecticut and Massachusetts, and the economic slowdown resulting from the COVID-19 pandemic. In Connecticut, the moratorium on disconnections of commercial and non-hardship residential customers ended in June 2021 and September 2021, respectively, but is still in place for hardship residential customers. In Massachusetts, the moratorium on disconnections of commercial customers and residential customers ended in September 2020 and July 2021, respectively. Disconnection activities have resumed after these moratoria have expired, which has resulted in recent improved collection experience, more customers applying for, and receiving, hardship status, and higher write-offs of aged receivable amounts. On July 7, 2021, the NHPUC issued an order to New Hampshire utilities that concluded that recovery of incremental bad debt or waived late fees related to the COVID-19 pandemic would be addressed in a future rate case to the extent those costs are relevant at that time. As a result of the order, PSNH removed its $0.6 million deferral of net incremental COVID-19 costs in 2021. In New Hampshire, the moratorium on disconnections of non-hardship residential and commercial customers ended in late 2020 and for hardship residential customers ended in May 2021 and PSNH has resumed disconnection activities, which has resulted in improved collection of outstanding customer receivable balances. Based upon the evaluation performed, for the year ended December 31, 2021, management increased the allowance for uncollectible accounts for amounts incurred as a result of COVID-19 by $24.1 million for Eversource (increase of $20.1 million for CL&P and $6.6 million at our natural gas businesses, and decrease of $1.3 million at NSTAR Electric). The COVID-19 related uncollectible amounts were deferred either as incremental regulatory costs at our Connecticut and Massachusetts utilities or deferred through existing regulatory tracking mechanisms that recover uncollectible energy supply costs, as management believes it is probable that these costs will ultimately be recovered from customers in future rates. As of December 31, 2021, the total amount incurred as a result of COVID-19 included in the allowance for uncollectible accounts was $55.3 million at Eversource ($23.9 million at CL&P, $9.0 million at NSTAR Electric, and $21.4 million at our natural gas businesses). Based on the status of our COVID-19 regulatory dockets, communications with our state regulatory commissions, and policies and practices in the jurisdictions in which we operate, we believe our state regulatory commissions in Connecticut and Massachusetts will allow us to recover our incremental costs associated with COVID-19, which include uncollectible customer receivable expenses, while balancing the impact on our customers’ bills and our operating cash flows. Management concluded that the reserve balance as of December 31, 2021 adequately reflected the collection risk and net realizable value for Eversource’s receivables. Management will continue to evaluate the adequacy of the uncollectible allowance in future reporting periods based on an ongoing assessment of accounts receivable collections, delinquency statistics, and analysis of aging-based quantitative assessments.
Transfer of Energy Efficiency Loans	Transfer of Energy Efficiency LoansCL&P transferred a portion of its energy efficiency customer loan portfolio to outside lenders in order to make additional loans to customers.  CL&P remains the servicer of the loans and will transmit customer payments to the lenders, with a maximum amount outstanding under this program of $55 million.  The amounts of the loans are included in Accounts Receivable, Net and Other Long-Term Assets, and are offset by Other Current Liabilities and Other Long-Term Liabilities on CL&P’s balance sheet.
Fuel, Materials, Supplies and REC Inventory	Fuel, Materials, Supplies and REC InventoryFuel, Materials, Supplies and REC Inventory include natural gas inventory, materials and supplies purchased primarily for construction or operation and maintenance purposes, and RECs.  Inventory is valued at the lower of cost or net realizable value. RECs are purchased from suppliers of renewable sources of generation and are used to meet state mandated Renewable Portfolio Standards requirements.
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, long-lived assets, equity method investments, and AROs, and in the valuation of the acquisition of CMA’s assets in 2020. The fair value measurement guidance was also applied in estimating the 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. The 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.
Derivative Accounting	Derivative Accounting Many of the electric and natural gas companies' contracts for the purchase and sale of energy or energy-related products are derivatives. The accounting treatment for energy contracts entered into varies and depends on the intended use of the particular contract and on whether or not the contract is a derivative. The application of derivative accounting is complex and requires management judgment in the following respects: identification of derivatives and embedded derivatives, election and designation of a contract as normal, and determination of the fair value of derivative contracts. All of these judgments can have a significant impact on the financial statements. The judgment applied in the election of a contract as normal (and resulting accrual accounting) includes the conclusion that it is probable at the inception of the contract and throughout its term that it will result in physical delivery of the underlying product and that the quantities will be used or sold by the business in the normal course of business. If facts and circumstances change and management can no longer support this conclusion, then a contract cannot be considered normal, accrual accounting is terminated, and fair value accounting is applied prospectively. The fair value of derivative contracts is based upon the contract terms and conditions and the underlying market price or fair value per unit. When quantities are not specified in the contract, the Company determines whether the contract has a determinable quantity by using amounts referenced in default provisions and other relevant sections of the contract. The fair value of derivative assets and liabilities with the same counterparty are offset and recorded as a net derivative asset or liability on the balance sheets. Regulatory assets or regulatory liabilities are recorded to offset the fair values of derivative contracts related to energy and energy-related products, as contract settlements are recovered from, or refunded to, customers in future rates. All changes in the fair value of derivative contracts are recorded as regulatory assets or liabilities and do not impact net income.
Allowance for Funds Used During Construction	Allowance for Funds Used During ConstructionAFUDC represents the cost of borrowed and equity funds used to finance construction and is included in the cost of the electric, natural gas and water companies' utility plant on the balance sheet.  The portion of AFUDC attributable to borrowed funds is recorded as a reduction of Interest Expense, and the AFUDC related to equity funds is recorded as Other Income, Net on the statements of income.  AFUDC costs are recovered from customers over the service life of the related plant in the form of increased revenue collected as a result of higher depreciation expense. The average AFUDC rate is based on a FERC-prescribed formula using the cost of a company's short-term financings and capitalization (preferred stock, long-term debt and common equity), as appropriate.  The average rate is applied to average eligible CWIP amounts to calculate AFUDC.
Other Taxes	Other TaxesEversource's companies that serve customers in Connecticut collect gross receipts taxes levied by the state of Connecticut from their customers. Separate from above were amounts recorded as Taxes Other Than Income Taxes at CL&P related to the remittance to the State of Connecticut of energy efficiency funds collected from customers of $21.4 million in 2019. 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. 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.
Related Parties	Related PartiesEversource Service, Eversource's service company, provides centralized accounting, administrative, engineering, financial, information technology, legal, operational, planning, purchasing, tax, and other services to Eversource's companies. The Rocky River Realty Company and Properties, Inc., two other Eversource subsidiaries, construct, acquire or lease some of the property and facilities used by Eversource's companies. As of both December 31, 2021 and 2020, CL&P, NSTAR Electric and PSNH had long-term receivables from Eversource Service in the amounts of $25.0 million, $5.5 million and $3.8 million, respectively, which were included in Other Long-Term Assets on the balance sheets. These amounts related to the funding of investments held in trust by Eversource Service in connection with certain postretirement benefits for CL&P, NSTAR Electric and PSNH employees and have been eliminated in consolidation on the Eversource financial statements. Included in the CL&P, NSTAR Electric and PSNH balance sheets as of December 31, 2021 and 2020 were Accounts Receivable from Affiliated Companies and Accounts Payable to Affiliated Companies relating to transactions between CL&P, NSTAR Electric and PSNH and other subsidiaries that are wholly-owned by Eversource. These amounts have been eliminated in consolidation on the Eversource financial statements. The Eversource Energy Foundation is an independent not-for-profit charitable entity and is not included in the consolidated financial statements of Eversource as the Company does not have title to, and cannot receive contributions back from, the Eversource Energy Foundation's assets. Eversource did not make any contributions to the Eversource Energy Foundation in 2021 and 2019, and made contributions of $6.4 million in 2020.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Provision for Uncollectible Accounts	The activity in the allowance for uncollectible accounts by portfolio segment is as follows: Eversource CL&P NSTAR Electric PSNH (Millions of Dollars) Hardship Accounts Retail (Non-Hardship), Total Allowance Hardship Accounts Retail (Non-Hardship), Total Allowance Hardship Accounts Retail (Non-Hardship), Total Allowance Total Allowance Balance as of January 1, 2020 $ 143.3 $ 81.5 $ 224.8 $ 80.1 $ 17.2 $ 97.3 $ 43.9 $ 31.5 $ 75.4 $ 10.5 ASU 2016-13 Implementation 21.6 2.2 23.8 21.3 0.9 22.2 (1.6) 0.3 (1.3) 0.3 Increase due to CMA acquisition — 24.2 24.2 — — — — — — — Uncollectible Expense (1) — 53.5 53.5 — 12.9 12.9 — 15.3 15.3 5.2 Uncollectible Costs Deferred (2) 43.1 53.9 97.0 38.2 10.8 49.0 (1.7) 26.4 24.7 7.4 Write-Offs (14.7) (63.3) (78.0) (11.9) (17.8) (29.7) (0.9) (26.3) (27.2) (6.9) Recoveries Collected 1.5 12.1 13.6 1.4 4.3 5.7 — 4.7 4.7 0.7 Balance as of December 31, 2020 $ 194.8 $ 164.1 $ 358.9 $ 129.1 $ 28.3 $ 157.4 $ 39.7 $ 51.9 $ 91.6 $ 17.2 Uncollectible Expense (1) — 60.9 60.9 — 13.5 13.5 — 16.6 16.6 13.1 Uncollectible Costs Deferred (2) 51.9 58.7 110.6 32.3 25.5 57.8 4.3 15.8 20.1 3.1 Write-Offs (22.0) (107.7) (129.7) (18.0) (36.2) (54.2) (0.7) (36.3) (37.0) (10.0) Recoveries Collected 1.4 15.3 16.7 1.2 5.6 6.8 — 5.7 5.7 0.9 Balance as of December 31, 2021 $ 226.1 $ 191.3 $ 417.4 $ 144.6 $ 36.7 $ 181.3 $ 43.3 $ 53.7 $ 97.0 $ 24.3 (1) Uncollectible expense associated with customer and other accounts receivable is included in Operations and Maintenance expense on the statements of income. For the year ended December 31, 2019, uncollectible expense included in Operations and Maintenance Expense was $63.4 million for Eversource, $15.9 million for CL&P, $25.1 million for NSTAR Electric and $6.7 million for PSNH. (2) These expected credit losses are deferred as regulatory costs on the balance sheets, as these amounts are ultimately recovered in rates. Amounts include uncollectible costs for hardship accounts and other customer receivables, including uncollectible amounts related to COVID-19 and uncollectible energy supply costs.
Schedule of Utility Inventory	The carrying amounts of fuel, materials and supplies, and RECs, which are included in Current Assets on the balance sheets, were as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Fuel $ 56.2 $ — $ — $ — $ 38.2 $ — $ — $ — Materials and Supplies 148.9 60.3 55.0 25.2 151.3 57.9 62.1 22.5 RECs 62.4 — 61.7 0.7 76.1 — 71.8 4.3 Total $ 267.5 $ 60.3 $ 116.7 $ 25.9 $ 265.6 $ 57.9 $ 133.9 $ 26.8
Costs Related to Fuel and Natural Gas	Costs related to fuel and natural gas included in Purchased Power, Fuel and Transmission on the statements of income were as follows: For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Eversource - Natural Gas and Fuel $ 718.6 $ 464.2 $ 462.1
Weighted-Average AFUDC Rates	AFUDC costs and the weighted-average AFUDC rates were as follows: Eversource For the Years Ended December 31, (Millions of Dollars, except percentages) 2021 2020 2019 Borrowed Funds $ 18.4 $ 23.7 $ 25.6 Equity Funds 37.3 42.0 45.0 Total AFUDC $ 55.7 $ 65.7 $ 70.6 Average AFUDC Rate 4.2 % 5.0 % 5.4 % For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars, CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Borrowed Funds $ 2.9 $ 9.0 $ 0.8 $ 6.6 $ 9.1 $ 2.1 $ 7.1 $ 10.4 $ 2.8 Equity Funds 7.7 20.4 1.6 13.8 21.5 4.2 13.2 19.8 3.4 Total AFUDC $ 10.6 $ 29.4 $ 2.4 $ 20.4 $ 30.6 $ 6.3 $ 20.3 $ 30.2 $ 6.2 Average AFUDC Rate 5.0 % 4.9 % 2.5 % 5.9 % 5.7 % 4.7 % 6.3 % 5.7 % 4.6 %
Components of Other Income, Net	The components of Other Income, Net on the statements of income were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Pension, SERP and PBOP Non-Service Income Components (1) $ 84.4 $ 44.4 $ 31.3 AFUDC Equity 37.3 42.0 45.0 Equity in Earnings of Unconsolidated Affiliates (2) 14.2 14.2 42.2 Investment (Loss)/Income (0.2) 1.1 0.8 Interest Income 25.6 4.8 12.8 Other — 2.1 0.7 Total Other Income, Net $ 161.3 $ 108.6 $ 132.8 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Pension, SERP and PBOP Non-Service Income Components (1) $ 15.2 $ 40.2 $ 10.3 $ 3.8 $ 29.3 $ 7.0 $ 0.5 $ 23.5 $ 4.9 AFUDC Equity 7.7 20.4 1.6 13.8 21.5 4.2 13.2 19.8 3.4 Equity in Earnings of Unconsolidated Affiliates — 0.4 — — 0.4 — 0.1 0.7 — Investment Income/(Loss) 1.3 0.1 0.1 1.1 (0.8) 0.1 2.3 (0.4) 0.3 Interest Income 5.9 13.4 2.4 2.0 0.9 2.4 1.5 0.7 10.5 Other 0.1 0.3 0.2 0.1 0.7 0.1 (0.1) 0.3 0.1 Total Other Income, Net $ 30.2 $ 74.8 $ 14.6 $ 20.8 $ 52.0 $ 13.8 $ 17.5 $ 44.6 $ 19.2 (1) See Note 11A, "Employee Benefits – Pension Benefits and Postretirement Benefits Other Than Pension," for the components of net periodic benefit cost for the Pension, SERP and PBOP Plans. The non-service related components of pension, SERP and PBOP benefit costs, after capitalization or deferral, are presented as non-operating income and recorded in Other Income, Net on the statements of income.
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 Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Eversource $ 181.9 $ 170.6 $ 163.1 CL&P 158.1 149.9 141.1
Supplemental Cash Flow Information	Eversource (Millions of Dollars) As of and For the Years Ended December 31, 2021 2020 2019 Cash Paid During the Year for: Interest, Net of Amounts Capitalized $ 568.7 $ 518.0 $ 532.4 Income Taxes 121.6 48.9 56.0 Non-Cash Investing Activities: Plant Additions Included in Accounts Payable (As of) 467.9 367.2 379.4 As of and For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Cash Paid During the Year for: Interest, Net of Amounts Capitalized $ 161.5 $ 141.6 $ 56.5 $ 149.0 $ 129.4 $ 54.5 $ 144.6 $ 121.9 $ 56.9 Income Taxes 38.4 74.2 51.1 10.9 110.7 34.2 80.6 77.9 3.4 Non-Cash Investing Activities: Plant Additions Included in Accounts 110.6 120.0 68.7 101.8 103.2 33.3 111.3 116.4 49.9
Cash and Cash Equivalents as Reported on the Balance Sheet	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 December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Cash as reported on the Balance Sheets $ 66.8 $ 55.8 $ 0.7 $ — $ 106.6 $ 90.8 $ 0.1 $ 0.1 Restricted cash included in: Special Deposits 78.2 18.7 17.4 31.4 73.6 8.7 17.2 36.8 Marketable Securities 31.3 0.3 0.1 0.5 41.2 0.3 0.1 0.6 Other Long-Term Assets 44.7 — — 3.2 43.6 — — 2.1 Cash and Restricted Cash as reported on the $ 221.0 $ 74.8 $ 18.2 $ 35.1 $ 265.0 $ 99.8 $ 17.4 $ 39.6

REGULATORY ACCOUNTING (Tables)

REGULATORY ACCOUNTING (Tables)	12 Months Ended
	Dec. 31, 2021
Regulated Operations [Abstract]
Components of Regulatory Assets	The components of regulatory assets were as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Benefit Costs $ 1,481.0 $ 272.4 $ 395.5 $ 118.9 $ 2,794.2 $ 632.3 $ 690.0 $ 267.6 Income Taxes, Net 790.7 470.5 112.6 17.5 747.1 458.9 110.4 15.2 Securitized Stranded Costs 478.9 — — 478.9 522.1 — — 522.1 Storm Costs, Net 1,102.7 695.6 341.3 65.8 765.6 515.1 186.4 64.1 Regulatory Tracker Mechanisms 1,050.5 333.6 376.6 85.4 850.5 246.6 332.2 95.3 Derivative Liabilities 249.2 249.2 — — 296.3 293.1 — — Goodwill-related 297.8 — 255.7 — 314.7 — 270.2 — Asset Retirement Obligations 115.0 33.6 59.8 4.1 118.4 32.1 58.6 3.9 Other Regulatory Assets 150.0 29.9 37.7 15.8 161.0 33.7 56.1 20.9 Total Regulatory Assets 5,715.8 2,084.8 1,579.2 786.4 6,569.9 2,211.8 1,703.9 989.1 Less: Current Portion 1,129.1 371.6 444.0 107.2 1,076.6 345.6 399.9 115.9 Total Long-Term Regulatory Assets $ 4,586.7 $ 1,713.2 $ 1,135.2 $ 679.2 $ 5,493.3 $ 1,866.2 $ 1,304.0 $ 873.2
Components of Regulatory Liabilities	The components of regulatory liabilities were as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH EDIT due to Tax Cuts and Jobs Act of 2017 $ 2,685.2 $ 996.1 $ 984.5 $ 359.2 $ 2,778.6 $ 1,010.7 $ 1,044.0 $ 371.5 Cost of Removal 649.6 100.1 381.0 17.2 624.8 98.4 363.6 12.9 Benefit Costs 133.5 — 107.4 — 83.6 — 72.5 — Regulatory Tracker Mechanisms 448.4 182.0 185.1 107.0 366.5 148.9 139.7 47.8 AFUDC - Transmission 81.0 43.2 37.8 — 76.8 44.6 32.2 — CL&P Settlement Agreement and Storm 81.3 81.3 — — — — — — Other Regulatory Liabilities 389.7 57.1 91.5 18.2 309.9 39.5 63.2 9.8 Total Regulatory Liabilities 4,468.7 1,459.8 1,787.3 501.6 4,240.2 1,342.1 1,715.2 442.0 Less: Current Portion 602.4 266.5 228.2 120.2 389.4 137.2 164.8 58.8 Total Long-Term Regulatory Liabilities $ 3,866.3 $ 1,193.3 $ 1,559.1 $ 381.4 $ 3,850.8 $ 1,204.9 $ 1,550.4 $ 383.2

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of Utility Property, Plant and Equipment	The following tables summarize property, plant and equipment by asset category: Eversource As of December 31, (Millions of Dollars) 2021 2020 Distribution - Electric $ 17,679.1 $ 16,703.2 Distribution - Natural Gas 6,694.8 6,111.2 Transmission - Electric 12,882.4 11,954.0 Distribution - Water 1,900.9 1,743.1 Solar 200.9 201.5 Utility 39,358.1 36,713.0 Other (1) 1,469.5 1,269.0 Property, Plant and Equipment, Gross 40,827.6 37,982.0 Less: Accumulated Depreciation Utility (8,885.2) (8,476.3) Other (580.1) (477.6) Total Accumulated Depreciation (9,465.3) (8,953.9) Property, Plant and Equipment, Net 31,362.3 29,028.1 Construction Work in Progress 2,015.4 1,854.4 Total Property, Plant and Equipment, Net $ 33,377.7 $ 30,882.5 As of December 31, 2021 2020 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH Distribution - Electric $ 7,117.6 $ 8,105.5 $ 2,496.2 $ 6,820.7 $ 7,544.4 $ 2,378.4 Transmission - Electric 5,859.0 5,090.5 1,934.6 5,512.0 4,701.3 1,742.4 Solar — 200.9 — — 201.5 — Property, Plant and Equipment, Gross 12,976.6 13,396.9 4,430.8 12,332.7 12,447.2 4,120.8 Less: Accumulated Depreciation (2,572.1) (3,227.3) (908.4) (2,475.4) (3,074.1) (848.9) Property, Plant and Equipment, Net 10,404.5 10,169.6 3,522.4 9,857.3 9,373.1 3,271.9 Construction Work in Progress 399.0 707.0 134.1 377.3 750.0 102.4 Total Property, Plant and Equipment, Net $ 10,803.5 $ 10,876.6 $ 3,656.5 $ 10,234.6 $ 10,123.1 $ 3,374.3 (1) These assets are primarily comprised of computer software, hardware and equipment at Eversource Service and buildings at The Rocky River Realty Company. The depreciation rates for the various classes of utility property, plant and equipment aggregate to composite rates as follows: (Percent) 2021 2020 2019 Eversource 3.1 % 3.0 % 3.0 % CL&P 2.8 % 2.8 % 2.8 % NSTAR Electric 2.8 % 2.8 % 2.8 % PSNH 3.1 % 2.8 % 2.8 % The following table summarizes average remaining useful lives of depreciable assets: As of December 31, 2021 (Years) Eversource CL&P NSTAR Electric PSNH Distribution - Electric 33.4 35.3 33.1 29.7 Distribution - Natural Gas 39.5 — — — Transmission - Electric 40.2 36.5 45.1 40.8 Distribution - Water 38.5 — — — Solar 24.2 — 24.2 — Other (1) 11.2 — — — (1) The estimated useful life of computer software, hardware and equipment primarily ranges from 5 to 15 years and of buildings is 40 years.

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	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 December 31, 2021 2020 (Millions of Dollars) Fair Value Hierarchy Commodity Supply Netting (1) Net Amount Commodity Supply Netting (1) Net Amount Current Derivative Assets: CL&P Level 3 $ 14.7 $ (1.0) $ 13.7 $ 13.7 $ (0.4) $ 13.3 Long-Term Derivative Assets: CL&P Level 3 46.9 (0.9) 46.0 58.7 (1.8) 56.9 Current Derivative Liabilities: CL&P Level 3 (73.5) — (73.5) (68.8) — (68.8) Other Level 2 — — — (3.3) 0.1 (3.2) Long-Term Derivative Liabilities: CL&P Level 3 (235.4) — (235.4) (294.5) — (294.5) (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.
Fair Value Inputs, Liabilities, Quantitative Information	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 December 31, 2021 2020 CL&P Range Weighted Average (1) Period Covered Range Weighted Average (1) Period Covered Capacity Prices $2.61 $ 2.61 per kW-Month 2025 - 2026 $ 4.30 — $5.30 $ 4.63 per kW-Month 2024 - 2026 Forward Reserve $ 0.50 — $1.15 $ 0.82 per kW-Month 2022 - 2024 $ 0.54 — $0.90 $ 0.72 per kW-Month 2021 - 2024
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation	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 (Millions of Dollars) For the Years Ended December 31, 2021 2020 Derivatives, Net: Fair Value as of Beginning of Period $ (293.1) $ (329.2) Net Realized/Unrealized Losses Included in Regulatory Assets (8.5) (17.9) Settlements 52.4 54.0 Fair Value as of End of Period $ (249.2) $ (293.1)

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following is a summary of the available-for-sale debt securities: As of December 31, 2021 2020 Eversource (Millions of Dollars) Amortized Pre-Tax Pre-Tax Fair Value Amortized Pre-Tax Pre-Tax Fair Value Debt Securities $ 214.5 $ 5.1 $ (0.2) $ 219.4 $ 213.1 $ 11.2 $ (0.1) $ 224.2
Investments Classified by Contractual Maturity Date	As of December 31, 2021, the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Fair Less than one year (1) $ 32.2 $ 32.2 One to five years 60.5 61.4 Six to ten years 35.7 36.8 Greater than ten years 86.1 89.0 Total Debt Securities $ 214.5 $ 219.4 (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	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 December 31, 2021 2020 Level 1: Mutual Funds and Equities $ 254.2 $ 246.0 Money Market Funds 31.3 41.2 Total Level 1 $ 285.5 $ 287.2 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 81.3 $ 72.9 Corporate Debt Securities 65.3 63.8 Asset-Backed Debt Securities 12.6 11.9 Municipal Bonds 12.3 24.0 Other Fixed Income Securities 16.6 10.4 Total Level 2 $ 188.1 $ 183.0 Total Marketable Securities $ 473.6 $ 470.2

INVESTMENTS IN UNCONSOLIDATED_2

INVESTMENTS IN UNCONSOLIDATED AFFILIATES (Tables)	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Summary of Investments	Eversource's investments included the following: Investment Balance as of December 31, (Millions of Dollars) Ownership Interest 2021 2020 Offshore Wind Business - North East Offshore 50 % $ 1,213.6 $ 887.1 Natural Gas Pipeline - Algonquin Gas Transmission, LLC 15 % 121.9 125.2 Renewable Energy Investment Fund 90 % 76.5 71.6 Other various 24.3 23.2 Total Investments in Unconsolidated Affiliates $ 1,436.3 $ 1,107.1

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation	A reconciliation of the beginning and ending carrying amounts of ARO liabilities is as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Balance as of Beginning of Year $ 499.7 $ 33.4 $ 91.8 $ 4.4 $ 489.5 $ 32.0 $ 97.5 $ 4.2 Liability Assumed Upon CMA Asset Acquisition — — — — 20.1 — — — Liabilities Incurred During the Year — — — — 2.1 — 2.1 — Liabilities Settled During the Year (23.9) (0.6) — — (21.8) (0.7) (1.0) — Accretion 29.4 2.2 4.0 0.3 28.9 2.1 4.3 0.2 Revisions in Estimated Cash Flows (5.1) — 1.7 — (19.1) — (11.1) — Balance as of End of Year $ 500.1 $ 35.0 $ 97.5 $ 4.7 $ 499.7 $ 33.4 $ 91.8 $ 4.4

SHORT-TERM DEBT (Tables)

SHORT-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Borrowings Outstanding	The amount of borrowings outstanding and available under the commercial paper programs were as follows: Borrowings Outstanding Available Borrowing Capacity as of December 31, Weighted-Average Interest Rate as of December 31, (Millions of Dollars) 2021 2020 2021 2020 2021 2020 Eversource Parent Commercial Paper Program $ 1,343.0 $ 1,054.3 $ 657.0 $ 945.7 0.31 % 0.25 % NSTAR Electric Commercial Paper Program 162.5 195.0 487.5 455.0 0.14 % 0.16 % Details of long-term debt outstanding are as follows: CL&P (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 7.875% 1994 Series D due 2024 $ 139.8 $ 139.8 5.750% 2004 Series B due 2034 130.0 130.0 5.625% 2005 Series B due 2035 100.0 100.0 6.350% 2006 Series A due 2036 250.0 250.0 5.750% 2007 Series B due 2037 150.0 150.0 6.375% 2007 Series D due 2037 100.0 100.0 2.500% 2013 Series A due 2023 400.0 400.0 4.300% 2014 Series A due 2044 475.0 475.0 4.150% 2015 Series A due 2045 350.0 350.0 3.200% 2017 Series A due 2027 500.0 500.0 4.000% 2018 Series A due 2048 800.0 800.0 0.750% 2020 Series A due 2025 400.0 400.0 2.050% 2021 Series A due 2031 425.0 — Total First Mortgage Bonds 4,219.8 3,794.8 Pollution Control Revenue Bonds: 4.375% Fixed Rate Tax Exempt due 2028 — 120.5 Unamortized Premiums and Discounts, Net 23.1 25.9 Unamortized Debt Issuance Costs (27.5) (26.4) CL&P Long-Term Debt $ 4,215.4 $ 3,914.8 NSTAR Electric (Millions of Dollars) As of December 31, 2021 2020 Debentures: 5.750% due 2036 $ 200.0 $ 200.0 5.500% due 2040 300.0 300.0 2.375% due 2022 400.0 400.0 4.400% due 2044 300.0 300.0 3.250% due 2025 250.0 250.0 2.700% due 2026 250.0 250.0 3.200% due 2027 700.0 700.0 3.250% due 2029 400.0 400.0 3.950% due 2030 400.0 400.0 3.100% due 2051 300.0 — 1.950% due 2031 300.0 — Total Debentures 3,800.0 3,200.0 Notes: 5.900% Senior Notes Series B due 2034 50.0 50.0 6.700% Senior Notes Series D due 2037 40.0 40.0 3.500% Senior Notes Series F due 2021 — 250.0 3.880% Senior Notes Series G due 2023 80.0 80.0 2.750% Senior Notes Series H due 2026 50.0 50.0 Total Notes 220.0 470.0 Less Amounts due Within One Year (400.0) (250.0) Unamortized Premiums and Discounts, Net (11.2) (6.8) Unamortized Debt Issuance Costs (23.4) (20.0) NSTAR Electric Long-Term Debt $ 3,585.4 $ 3,393.2 PSNH (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 5.600% Series M due 2035 $ 50.0 $ 50.0 4.050% Series Q due 2021 — 122.0 3.200% Series R due 2021 — 160.0 3.500% Series S due 2023 325.0 325.0 3.600% Series T due 2049 300.0 300.0 2.400% Series U due 2050 150.0 150.0 2.200% Series V due 2031 350.0 — Total First Mortgage Bonds 1,175.0 1,107.0 Less Amounts due Within One Year — (282.0) Unamortized Premiums and Discounts, Net (2.6) (1.5) Unamortized Debt Issuance Costs (8.6) (6.4) PSNH Long-Term Debt $ 1,163.8 $ 817.1 OTHER (Millions of Dollars) As of December 31, 2021 2020 Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 $ 765.0 $ 640.0 NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 580.0 500.0 EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051 550.0 — Aquarion - Senior Notes 4.000% due 2024 360.0 360.0 Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051 394.9 335.2 Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044 39.6 35.9 Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050 6,100.0 5,550.0 Pre-1983 Spent Nuclear Fuel Obligation (CYAPC) 11.7 11.7 Fair Value Adjustment (1) 43.8 74.7 Less Fair Value Adjustment - Current Portion (1) (17.7) (31.0) Less Amounts due in One Year (775.4) (490.2) Unamortized Premiums and Discounts, Net 43.4 46.5 Unamortized Debt Issuance Costs (36.3) (32.0) Total Other Long-Term Debt $ 8,059.0 $ 7,000.8 Total Eversource Long-Term Debt $ 17,023.6 $ 15,125.9 (1) The fair value adjustment amount is the purchase price adjustments, net of amortization, required to record long-term debt at fair value on the dates of the 2012 merger with NSTAR and the 2017 acquisition of Aquarion. Availability under Long-Term Debt Issuance Authorizations: On March 31, 2021, the DPU approved NSTAR Electric's request for authorization to issue up to $1.60 billion in long-term debt through December 31, 2023. On September 10, 2021, the DPU approved EGMA’s request for authorization to issue up to $725.0 million in long-term debt through December 31, 2023. The remaining Eversource operating companies, including CL&P and PSNH, have utilized the long-term debt authorizations in place with the respective regulatory commissions.

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Outstanding Long-Term Debt	The amount of borrowings outstanding and available under the commercial paper programs were as follows: Borrowings Outstanding Available Borrowing Capacity as of December 31, Weighted-Average Interest Rate as of December 31, (Millions of Dollars) 2021 2020 2021 2020 2021 2020 Eversource Parent Commercial Paper Program $ 1,343.0 $ 1,054.3 $ 657.0 $ 945.7 0.31 % 0.25 % NSTAR Electric Commercial Paper Program 162.5 195.0 487.5 455.0 0.14 % 0.16 % Details of long-term debt outstanding are as follows: CL&P (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 7.875% 1994 Series D due 2024 $ 139.8 $ 139.8 5.750% 2004 Series B due 2034 130.0 130.0 5.625% 2005 Series B due 2035 100.0 100.0 6.350% 2006 Series A due 2036 250.0 250.0 5.750% 2007 Series B due 2037 150.0 150.0 6.375% 2007 Series D due 2037 100.0 100.0 2.500% 2013 Series A due 2023 400.0 400.0 4.300% 2014 Series A due 2044 475.0 475.0 4.150% 2015 Series A due 2045 350.0 350.0 3.200% 2017 Series A due 2027 500.0 500.0 4.000% 2018 Series A due 2048 800.0 800.0 0.750% 2020 Series A due 2025 400.0 400.0 2.050% 2021 Series A due 2031 425.0 — Total First Mortgage Bonds 4,219.8 3,794.8 Pollution Control Revenue Bonds: 4.375% Fixed Rate Tax Exempt due 2028 — 120.5 Unamortized Premiums and Discounts, Net 23.1 25.9 Unamortized Debt Issuance Costs (27.5) (26.4) CL&P Long-Term Debt $ 4,215.4 $ 3,914.8 NSTAR Electric (Millions of Dollars) As of December 31, 2021 2020 Debentures: 5.750% due 2036 $ 200.0 $ 200.0 5.500% due 2040 300.0 300.0 2.375% due 2022 400.0 400.0 4.400% due 2044 300.0 300.0 3.250% due 2025 250.0 250.0 2.700% due 2026 250.0 250.0 3.200% due 2027 700.0 700.0 3.250% due 2029 400.0 400.0 3.950% due 2030 400.0 400.0 3.100% due 2051 300.0 — 1.950% due 2031 300.0 — Total Debentures 3,800.0 3,200.0 Notes: 5.900% Senior Notes Series B due 2034 50.0 50.0 6.700% Senior Notes Series D due 2037 40.0 40.0 3.500% Senior Notes Series F due 2021 — 250.0 3.880% Senior Notes Series G due 2023 80.0 80.0 2.750% Senior Notes Series H due 2026 50.0 50.0 Total Notes 220.0 470.0 Less Amounts due Within One Year (400.0) (250.0) Unamortized Premiums and Discounts, Net (11.2) (6.8) Unamortized Debt Issuance Costs (23.4) (20.0) NSTAR Electric Long-Term Debt $ 3,585.4 $ 3,393.2 PSNH (Millions of Dollars) As of December 31, 2021 2020 First Mortgage Bonds: 5.600% Series M due 2035 $ 50.0 $ 50.0 4.050% Series Q due 2021 — 122.0 3.200% Series R due 2021 — 160.0 3.500% Series S due 2023 325.0 325.0 3.600% Series T due 2049 300.0 300.0 2.400% Series U due 2050 150.0 150.0 2.200% Series V due 2031 350.0 — Total First Mortgage Bonds 1,175.0 1,107.0 Less Amounts due Within One Year — (282.0) Unamortized Premiums and Discounts, Net (2.6) (1.5) Unamortized Debt Issuance Costs (8.6) (6.4) PSNH Long-Term Debt $ 1,163.8 $ 817.1 OTHER (Millions of Dollars) As of December 31, 2021 2020 Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 $ 765.0 $ 640.0 NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 580.0 500.0 EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051 550.0 — Aquarion - Senior Notes 4.000% due 2024 360.0 360.0 Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051 394.9 335.2 Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044 39.6 35.9 Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050 6,100.0 5,550.0 Pre-1983 Spent Nuclear Fuel Obligation (CYAPC) 11.7 11.7 Fair Value Adjustment (1) 43.8 74.7 Less Fair Value Adjustment - Current Portion (1) (17.7) (31.0) Less Amounts due in One Year (775.4) (490.2) Unamortized Premiums and Discounts, Net 43.4 46.5 Unamortized Debt Issuance Costs (36.3) (32.0) Total Other Long-Term Debt $ 8,059.0 $ 7,000.8 Total Eversource Long-Term Debt $ 17,023.6 $ 15,125.9 (1) The fair value adjustment amount is the purchase price adjustments, net of amortization, required to record long-term debt at fair value on the dates of the 2012 merger with NSTAR and the 2017 acquisition of Aquarion. Availability under Long-Term Debt Issuance Authorizations: On March 31, 2021, the DPU approved NSTAR Electric's request for authorization to issue up to $1.60 billion in long-term debt through December 31, 2023. On September 10, 2021, the DPU approved EGMA’s request for authorization to issue up to $725.0 million in long-term debt through December 31, 2023. The remaining Eversource operating companies, including CL&P and PSNH, have utilized the long-term debt authorizations in place with the respective regulatory commissions.
Schedule of Issuance and Repayments of Long-Term Debt	The following table summarizes long-term debt issuances and repayments: (Millions of Dollars) Issuance/(Repayment) Issue Date or Repayment Date Maturity Date Use of Proceeds for Issuance/ CL&P: 2.05% Series A First Mortgage Bonds $ 425.0 June 2021 July 2031 Repaid short-term debt, paid capital expenditures and working capital 4.38% Series A PCRB (120.5) September 2021 September 2028 Paid on par call date in advance of maturity NSTAR Electric: 3.10% 2021 Debentures 300.0 May 2021 June 2051 Refinanced investments in eligible green expenditures, which were previously financed in 2019 and 2020 3.50% Series F Senior Notes (250.0) June 2021 September 2021 Paid on par call date in advance of maturity 1.95% 2021 Debentures 300.0 August 2021 August 2031 Repaid short-term debt, paid capital expenditures and working capital PSNH: 4.05% Series Q First Mortgage Bonds (122.0) March 2021 June 2021 Paid on par call date in advance of maturity 3.20% Series R First Mortgage Bonds (160.0) June 2021 September 2021 Paid on par call date in advance of maturity 2.20% Series V First Mortgage Bonds 350.0 June 2021 June 2031 Repaid short-term debt, including short-term debt used to redeem Series R First Mortgage Bonds, paid capital expenditures and working capital Other: Eversource Parent 2.50% Series I Senior Notes (450.0) February 2021 March 2021 Paid on par call date in advance of maturity Eversource Parent 2.55% Series S Senior Notes 350.0 March 2021 March 2031 Repaid short-term debt, including short-term debt used to redeem Series I Senior Notes Eversource Parent 1.40% Series U Senior Notes 300.0 August 2021 August 2026 Repaid short-term debt Eversource Parent Variable Rate Series T Senior Notes (1) 350.0 August 2021 August 2023 Repaid short-term debt Aquarion Water Company of Connecticut 3.31% Senior Notes 100.0 April 2021 April 2051 Repaid 5.50% Notes, repaid short-term debt, paid capital expenditures and working capital Aquarion Water Company of Connecticut 5.50% Notes (40.0) April 2021 April 2021 Paid at maturity Yankee Gas 1.38% Series S First Mortgage Bonds 90.0 August 2021 August 2026 (2) Yankee Gas 2.88% Series T First Mortgage Bonds 35.0 August 2021 August 2051 (2) EGMA 2.11% Series A First Mortgage Bonds 310.0 September 2021 October 2031 (2) EGMA 2.92% Series B First Mortgage Bonds 240.0 September 2021 October 2051 (2) NSTAR Gas 2.25% Series T First Mortgage Bonds 40.0 October 2021 November 2031 (2) NSTAR Gas 3.03% Series U First Mortgage Bonds 40.0 October 2021 November 2051 (2) (1) On August 13, 2021, Eversource Parent issued $350 million of floating rate Series T Senior Notes with a maturity date of August 15, 2023. The notes have a coupon rate based on Compounded SOFR plus 0.25%. The notes had an interest rate of 0.30% as of December 31, 2021. (2) The use of proceeds from these various issuances refinanced existing indebtedness, funded capital expenditures and were for general corporate purposes. The EGMA indebtedness that was refinanced included $309.4 million of long-term debt.
Schedule of Maturities of Long-Term Debt Outstanding	Long-term debt maturities on debt outstanding for the years 2022 through 2026 and thereafter are shown below. These amounts exclude PSNH rate reduction bonds, CYAPC pre-1983 spent nuclear fuel obligation, net unamortized premiums, discounts and debt issuance costs, and other fair value adjustments as of December 31, 2021: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2022 $ 1,175.4 $ — $ 400.0 $ — 2023 2,008.4 400.0 80.0 325.0 2024 1,050.1 139.8 — — 2025 1,400.2 400.0 250.0 — 2026 940.2 — 300.0 — Thereafter 11,630.0 3,280.0 2,990.0 850.0 Total $ 18,204.3 $ 4,219.8 $ 4,020.0 $ 1,175.0

RATE REDUCTION BONDS AND VARI_2

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES (Tables)	12 Months Ended
	Dec. 31, 2021
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) As of December 31, PSNH Balance Sheets: 2021 2020 Restricted Cash - Current Portion (included in Current Assets) $ 31.1 $ 36.8 Restricted Cash - Long-Term Portion (included in Other Long-Term Assets) 3.2 2.1 Securitized Stranded Cost (included in Regulatory Assets) 478.9 522.1 Other Regulatory Liabilities (included in Regulatory Liabilities) 5.4 9.1 Accrued Interest (included in Other Current Liabilities) 7.5 8.0 Rate Reduction Bonds - Current Portion 43.2 43.2 Rate Reduction Bonds - Long-Term Portion 453.7 496.9 (Millions of Dollars) PSNH Income Statements: For the Years Ended December 31, 2021 2020 2019 Amortization of RRB Principal (included in Amortization of Regulatory Assets, Net) $ 43.2 $ 43.2 $ 43.0 Interest Expense on RRB Principal (included in Interest Expense) 18.4 19.7 21.1
Schedule Of Rate Reduction Bonds, Principal And Interest Payments	Estimated principal and interest payments on RRBs as of December 31, 2021, is summarized annually through 2026 and thereafter as follows: (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Eversource $ 43.2 $ 43.2 $ 43.2 $ 43.2 $ 43.2 $ 280.9 $ 496.9

EMPLOYEE BENEFITS (Tables)

EMPLOYEE BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets	The following tables provide information on the plan benefit obligations, fair values of plan assets, and funded status: Pension and SERP As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Change in Benefit Obligation: Benefit Obligation as of Beginning of Year $ (7,045.3) $ (1,477.3) $ (1,517.9) $ (748.7) $ (6,321.7) $ (1,331.3) $ (1,397.3) $ (692.6) Service Cost (85.8) (23.0) (15.8) (8.9) (76.2) (21.8) (15.4) (8.2) Interest Cost (130.0) (27.3) (26.8) (14.5) (177.8) (37.3) (38.6) (19.4) Actuarial Gain/(Loss) 177.1 127.8 20.8 14.7 (658.2) (152.3) (139.5) (62.1) Benefits Paid - Pension 309.5 64.6 68.7 34.7 279.3 63.6 59.4 33.5 Benefits Paid - Lump Sum 34.7 — 15.6 — 23.4 — 13.1 — Benefits Paid - SERP 10.1 0.3 0.2 0.4 7.3 0.3 0.2 0.4 Employee Transfers — 4.0 6.8 1.3 — 1.5 0.2 (0.3) Increase due to acquisition of CMA — — — — (121.4) — — — Benefit Obligation as of End of Year $ (6,729.7) $ (1,330.9) $ (1,448.4) $ (721.0) $ (7,045.3) $ (1,477.3) $ (1,517.9) $ (748.7) Change in Pension Plan Assets: Fair Value of Pension Plan Assets as of $ 5,409.2 $ 1,043.1 $ 1,345.1 $ 593.7 $ 4,968.6 $ 986.2 $ 1,288.8 $ 551.6 Employer Contributions 180.0 98.9 30.0 — 109.6 23.2 0.7 19.5 Actual Return on Pension Plan Assets 1,250.5 250.4 312.0 136.9 512.3 98.8 128.3 55.8 Benefits Paid - Pension (309.5) (64.6) (68.7) (34.7) (279.3) (63.6) (59.4) (33.5) Benefits Paid - Lump Sum (34.7) — (15.6) — (23.4) — (13.1) — Employee Transfers — (4.0) (6.8) (1.3) — (1.5) (0.2) 0.3 Increase due to acquisition of CMA — — — — 121.4 — — — Fair Value of Pension Plan Assets as of End of Year $ 6,495.5 $ 1,323.8 $ 1,596.0 $ 694.6 $ 5,409.2 $ 1,043.1 $ 1,345.1 $ 593.7 Funded Status as of December 31st $ (234.2) $ (7.1) $ 147.6 $ (26.4) $ (1,636.1) $ (434.2) $ (172.8) $ (155.0) PBOP As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Change in Benefit Obligation: Benefit Obligation as of Beginning of Year $ (993.9) $ (178.6) $ (260.5) $ (109.5) $ (899.0) $ (172.7) $ (258.3) $ (93.0) Service Cost (13.5) (2.3) (2.4) (1.2) (10.2) (1.7) (2.1) (0.9) Interest Cost (17.4) (3.2) (4.4) (1.8) (24.6) (4.4) (6.6) (2.8) Actuarial Gain/(Loss) 81.4 5.8 11.5 14.6 (82.8) (8.6) (7.4) (19.0) Benefits Paid 51.7 10.9 16.3 5.6 50.2 10.1 14.9 6.1 Employee Transfers — 1.9 1.1 — — (1.3) (1.0) 0.1 Impact of Acquisition of CMA 7.4 — — — (27.5) — — — Benefit Obligation as of End of Year $ (884.3) $ (165.5) $ (238.4) $ (92.3) $ (993.9) $ (178.6) $ (260.5) $ (109.5) Change in Plan Assets: Fair Value of Plan Assets as of Beginning of Year $ 1,004.1 $ 134.1 $ 464.6 $ 79.4 $ 935.9 $ 126.3 $ 424.4 $ 76.0 Actual Return on Plan Assets 183.2 24.1 84.2 14.2 116.5 15.7 53.3 9.3 Employer Contributions 2.3 — — — 1.9 — — — Benefits Paid (51.3) (10.9) (16.3) (5.6) (50.2) (10.1) (14.9) (6.1) Employee Transfers — (1.6) (2.5) — — 2.2 1.8 0.2 Fair Value of Plan Assets as of End of Year $ 1,138.3 $ 145.7 $ 530.0 $ 88.0 $ 1,004.1 $ 134.1 $ 464.6 $ 79.4 Funded Status as of December 31st $ 254.0 $ (19.8) $ 291.6 $ (4.3) $ 10.2 $ (44.5) $ 204.1 $ (30.1)
Schedule of Defined Benefit Plans	As of December 31, 2021 and 2020, the accumulated benefit obligation for the Pension and SERP Plans is as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2021 $ 6,337.3 $ 1,241.1 $ 1,376.1 $ 670.3 2020 6,669.4 1,356.4 1,449.4 707.2
Schedule of Assumptions Used	The following actuarial assumptions were used in calculating the Pension, SERP and PBOP Plans' year end funded status: Pension and SERP PBOP As of December 31, As of December 31, 2021 2020 2021 2020 Discount Rate 2.8% — 3.0% 2.4% — 2.7% 2.91% — 2.92% 2.5% — 2.6% Compensation/Progression Rate 3.5% — 4.0% 3.5% — 4.0% N/A The following actuarial assumptions were used to calculate Pension, SERP and PBOP expense amounts: Pension and SERP PBOP For the Years Ended December 31, For the Years Ended December 31, 2021 2020 2019 2021 2020 2019 Discount Rate 1.5% — 3.0% 2.6% — 3.5% 2.7% — 3.6% 1.8% — 3.1% 2.7% — 3.6% 3.9% — 4.6% Expected Long-Term Rate of Return 8.25% 8.25% 8.25% 8.25% 8.25% 8.25% Compensation/Progression Rate 3.5% — 4.0% 3.5% — 4.0% 3.5% — 4.0% N/A N/A N/A
Schedule of Net Benefit Costs	The components of net periodic benefit plan expense/(income) for the Pension, SERP and PBOP Plans, prior to amounts capitalized as Property, Plant and Equipment or deferred as regulatory assets/(liabilities) for future recovery or refund, are shown below. The service cost component of net periodic benefit plan expense/(income), less the capitalized portion, is included in Operations and Maintenance expense on the statements of income. The remaining components of net periodic benefit plan 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 intercompany allocations of net periodic benefit plan expense/(income), as these amounts are cash settled on a short-term basis. Pension and SERP PBOP For the Year Ended December 31, 2021 For the Year Ended December 31, 2021 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 85.8 $ 23.0 $ 15.8 $ 8.9 $ 13.5 $ 2.3 $ 2.4 $ 1.2 Interest Cost 130.0 27.3 26.8 14.5 17.4 3.2 4.4 1.8 Expected Return on Plan Assets (437.5) (86.8) (108.1) (47.5) (79.1) (10.3) (36.9) (6.1) Actuarial Loss 243.9 45.5 61.6 20.7 8.9 1.8 2.4 0.7 Prior Service Cost/(Credit) 1.4 — 0.3 — (21.2) 1.1 (17.0) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 23.6 $ 9.0 $ (3.6) $ (3.4) $ (60.5) $ (1.9) $ (44.7) $ (2.0) Intercompany Expense/(Income) Allocations N/A $ 8.0 $ 8.8 $ 2.7 N/A $ (1.6) $ (1.9) $ (0.6) Pension and SERP PBOP For the Year Ended December 31, 2020 For the Year Ended December 31, 2020 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 76.2 $ 21.8 $ 15.4 $ 8.2 $ 10.2 $ 1.7 $ 2.1 $ 0.9 Interest Cost 177.8 37.3 38.6 19.4 24.6 4.4 6.6 2.8 Expected Return on Plan Assets (400.3) (79.2) (103.0) (44.7) (73.6) (9.9) (34.0) (5.7) Actuarial Loss 202.0 39.2 55.2 15.6 8.4 1.1 2.5 0.8 Prior Service Cost/(Credit) 1.2 — 0.3 — (21.2) 1.1 (17.0) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 56.9 $ 19.1 $ 6.5 $ (1.5) $ (51.6) $ (1.6) $ (39.8) $ (0.8) Intercompany Expense/(Income) Allocations N/A $ 9.1 $ 8.9 $ 2.9 N/A $ (1.1) $ (1.4) $ (0.5) Pension and SERP PBOP For the Year Ended December 31, 2019 For the Year Ended December 31, 2019 (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Service Cost $ 67.7 $ 18.0 $ 14.6 $ 7.1 $ 7.8 $ 1.4 $ 1.7 $ 0.7 Interest Cost 219.0 45.7 49.0 24.0 32.7 6.3 9.5 3.4 Expected Return on Plan Assets (367.1) (73.2) (97.1) (40.7) (66.8) (9.2) (30.2) (5.4) Actuarial Loss 143.2 26.9 44.7 10.6 8.3 1.3 3.3 0.3 Prior Service Cost/(Credit) 0.9 — 0.3 — (23.5) 1.1 (16.9) 0.4 Total Net Periodic Benefit Plan Expense/(Income) $ 63.7 $ 17.4 $ 11.5 $ 1.0 $ (41.5) $ 0.9 $ (32.6) $ (0.6) Intercompany Expense/(Income) Allocations N/A $ 8.5 $ 8.0 $ 2.3 N/A $ (0.9) $ (1.2) $ (0.4)
Schedule of Amounts Recognized in Regulatory Assets and OCI	The following is a summary of the changes in plan assets and benefit obligations recognized in Regulatory Assets and Other Comprehensive Income (OCI) as well as amounts in Regulatory Assets and OCI that were reclassified as net periodic benefit expense during the years presented: Pension and SERP PBOP Regulatory Assets OCI Regulatory Assets OCI For the Years Ended December 31, For the Years Ended December 31, (Millions of Dollars) 2021 2020 (1) 2021 2020 2021 2020 (1) 2021 2020 Actuarial (Gains)/Losses Arising During the Year $ (961.7) $ 553.1 $ (28.4) $ 24.3 $ (181.5) $ 39.1 $ (4.0) $ 1.3 Actuarial Losses Reclassified as Net Periodic Benefit Expense (231.2) (194.3) (12.7) (7.7) (8.5) (8.0) (0.4) (0.4) Prior Service Cost Arising During the Year — 2.0 — — — — — — Prior Service (Cost)/Credit Reclassified as Net Periodic (1.3) (1.0) (0.1) (0.2) 21.1 21.3 0.1 (0.1) (1) Amounts include the impact of the CMA asset acquisition beginning October 9, 2020. The following is a summary of the remaining Regulatory Assets and Accumulated Other Comprehensive Income amounts that have not been recognized as components of net periodic benefit expense as of December 31, 2021 and 2020: Regulatory Assets as of December 31, AOCI as of December 31, (Millions of Dollars) 2021 2020 2021 2020 Pension and SERP Actuarial Loss $ 1,427.3 $ 2,620.2 $ 66.3 $ 107.4 Prior Service Cost 5.3 6.6 0.6 0.7 PBOP Actuarial Loss $ 45.0 $ 235.0 $ 3.5 $ 7.9 Prior Service (Credit)/Cost (130.1) (151.2) 1.0 0.9
Schedule of Expected Benefit Payments	The following benefit payments, which reflect expected future service, are expected to be paid by the Pension, SERP and PBOP Plans: (Millions of Dollars) 2022 2023 2024 2025 2026 2027 - 2031 Pension and SERP $ 359.6 $ 367.4 $ 405.0 $ 381.2 $ 384.3 $ 1,918.2 PBOP 56.4 56.2 55.9 55.3 54.3 254.6
Schedule of Allocation of Plan Assets	These long-term rates of return are based on the assumed rates of return for the target asset allocations as follows: As of December 31, 2021 2020 Eversource Pension Plan and PBOP Plan Eversource Pension Plan and PBOP Plan Target Asset Allocation Assumed Rate of Return Target Asset Allocation Assumed Rate of Return Equity Securities: United States 15.0 % 8.5 % 15.0 % 8.5 % Global 10.0 % 8.75 % 10.0 % 8.75 % Non-United States 8.0 % 8.5 % 8.0 % 8.5 % Emerging Markets 4.0 % 10.0 % 4.0 % 10.0 % Debt Securities: Fixed Income 13.0 % 4.0 % 13.0 % 4.0 % Public High Yield Fixed Income 4.0 % 6.5 % 4.0 % 6.5 % Private Debt 13.0 % 9.0 % 15.0 % 9.0 % Private Equity 18.0 % 12.0 % 15.0 % 12.0 % Real Assets 15.0 % 7.5 % 16.0 % 7.5 % The following table presents, by asset category, the Pension and PBOP Plan assets recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Pension Plan Fair Value Measurements as of December 31, (Millions of Dollars) 2021 2020 Asset Category: Level 1 Level 2 Uncategorized Total Level 1 Level 2 Uncategorized Total Equity Securities $ 722.5 $ — $ 1,385.2 $ 2,107.7 $ 630.8 $ — $ 1,321.7 $ 1,952.5 Fixed Income 139.6 233.8 1,689.1 2,062.5 113.6 265.6 1,402.5 1,781.7 Private Equity — — 1,702.7 1,702.7 22.3 — 1,175.4 1,197.7 Real Assets 218.3 — 702.8 921.1 158.4 — 580.8 739.2 Total $ 1,080.4 $ 233.8 $ 5,479.8 $ 6,794.0 $ 925.1 $ 265.6 $ 4,480.4 $ 5,671.1 Less: 401(h) PBOP Assets (1) (298.5) (261.9) Total Pension Assets $ 6,495.5 $ 5,409.2 PBOP Plan Fair Value Measurements as of December 31, (Millions of Dollars) 2021 2020 Asset Category: Level 1 Level 2 Uncategorized Total Level 1 Level 2 Uncategorized Total Equity Securities $ 191.4 $ — $ 248.3 $ 439.7 $ 176.5 $ — $ 217.8 $ 394.3 Fixed Income 49.7 45.2 125.5 220.4 16.0 43.2 152.9 212.1 Private Equity — — 58.7 58.7 — — 31.5 31.5 Real Assets 90.0 — 31.0 121.0 82.1 — 22.2 104.3 Total $ 331.1 $ 45.2 $ 463.5 $ 839.8 $ 274.6 $ 43.2 $ 424.4 $ 742.2 Add: 401(h) PBOP Assets (1) 298.5 261.9 Total PBOP Assets $ 1,138.3 $ 1,004.1 (1) The assets of the Pension Plan include a 401(h) account that has been allocated to provide health and welfare postretirement benefits under the PBOP Plan.
Schedule of Defined Contribution Plans	The total Eversource 401k Plan employer matching contributions, including the K-Vantage contributions, were as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH 2021 $ 55.5 $ 7.0 $ 12.2 $ 4.3 2020 49.4 6.6 11.8 4.1 2019 41.6 5.5 10.3 3.5
Summary of Share Transactions	A summary of RSU transactions is as follows: RSUs Weighted Average Outstanding as of December 31, 2020 674,218 $ 63.42 Granted 165,930 $ 81.89 Shares Issued (223,484) $ 69.03 Forfeited (22,041) $ 83.86 Outstanding as of December 31, 2021 594,623 $ 65.70 Performance Shares Weighted Average Outstanding as of December 31, 2020 447,805 $ 69.93 Granted 286,645 $ 76.08 Shares Issued (256,914) $ 56.88 Forfeited (13,029) $ 84.28 Outstanding as of December 31, 2021 464,507 $ 80.54
Schedule of Compensation Expense and Income Tax Benefit	The total compensation expense and associated future income tax benefits recognized by Eversource, CL&P, NSTAR Electric and PSNH for share-based compensation awards were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Compensation Expense $ 28.2 $ 33.9 $ 27.3 Future Income Tax Benefit 7.3 8.9 7.0 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Compensation Expense $ 8.8 $ 9.0 $ 3.0 $ 10.9 $ 11.3 $ 3.6 $ 9.8 $ 9.7 $ 3.3 Future Income Tax Benefit 2.3 2.3 0.8 2.9 3.0 1.0 2.5 2.5 0.8
Schedule of Other Retirement Benefits	The liability and expense amounts are as follows: Eversource (Millions of Dollars) As of and For the Years Ended December 31, 2021 2020 2019 Actuarially-Determined Liability $ 42.8 $ 45.7 $ 52.0 Other Retirement Benefits Expense 2.2 3.3 2.7 As of and For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Actuarially-Determined Liability $ 0.2 $ 0.1 $ 1.5 $ 0.2 $ 0.1 $ 1.7 $ 0.2 $ 0.1 $ 1.7 Other Retirement Benefits Expense 0.7 0.7 0.3 1.2 1.1 0.5 1.0 0.9 0.4

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	The components of income tax expense are as follows: Eversource (Millions of Dollars) For the Years Ended December 31, 2021 2020 2019 Current Income Taxes: Federal $ 21.5 $ 73.6 $ 56.9 State (21.6) 19.1 10.5 Total Current (0.1) 92.7 67.4 Deferred Income Taxes, Net: Federal 199.7 173.5 138.4 State 147.4 83.7 71.4 Total Deferred 347.1 257.2 209.8 Investment Tax Credits, Net (2.8) (3.7) (3.7) Income Tax Expense $ 344.2 $ 346.2 $ 273.5 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Current Income Taxes: Federal $ 15.0 $ 52.3 $ 43.1 $ 12.0 $ 53.9 $ 20.6 $ 68.4 $ 82.6 $ 22.9 State (7.0) 6.2 10.8 (6.1) 6.9 3.8 15.4 18.2 2.2 Total Current 8.0 58.5 53.9 5.9 60.8 24.4 83.8 100.8 25.1 Deferred Income Taxes, Net: Federal 76.3 16.3 (14.9) 101.1 33.8 (1.3) 35.2 0.1 5.8 State 47.6 41.2 0.4 43.4 38.8 8.6 18.8 27.0 10.1 Total Deferred 123.9 57.5 (14.5) 144.5 72.6 7.3 54.0 27.1 15.9 Investment Tax Credits, Net (0.6) (1.7) — (0.7) (2.6) — (0.8) (2.6) — Income Tax Expense $ 131.3 $ 114.3 $ 39.4 $ 149.7 $ 130.8 $ 31.7 $ 137.0 $ 125.3 $ 41.0
Summary of Reconciliation Between Income Tax Expense and Expected Tax	A reconciliation between income tax expense and the expected tax expense at the statutory rate is as follows: Eversource (Millions of Dollars, except percentages) For the Years Ended December 31, 2021 2020 2019 Income Before Income Tax Expense $ 1,572.3 $ 1,558.9 $ 1,190.1 Statutory Federal Income Tax Expense at 21% 330.2 327.4 249.9 Tax Effect of Differences: Depreciation (18.1) (11.1) 1.9 Investment Tax Credit Amortization (2.8) (3.7) (3.7) State Income Taxes, Net of Federal Impact 54.4 44.9 24.6 Dividends on ESOP (5.1) (5.1) (5.1) Tax Asset Valuation Allowance/Reserve Adjustments 44.6 33.4 40.1 Excess Stock Benefit (4.0) (6.6) (1.5) EDIT Amortization (69.1) (48.7) (37.4) Other, Net 14.1 15.7 4.7 Income Tax Expense $ 344.2 $ 346.2 $ 273.5 Effective Tax Rate 21.9 % 22.2 % 23.0 % For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars, except percentages) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Income Before Income Tax Expense $ 533.0 $ 590.9 $ 189.8 $ 607.6 $ 575.8 $ 179.0 $ 547.8 $ 557.3 $ 175.0 Statutory Federal Income Tax Expense at 21% 111.9 124.1 39.9 127.6 120.9 37.6 115.0 117.0 36.8 Tax Effect of Differences: Depreciation (6.4) (3.4) (0.2) 0.4 (3.7) (1.4) (0.2) (3.0) (0.8) Investment Tax Credit Amortization (0.6) (1.7) — (0.7) (2.6) — (0.8) (2.6) — State Income Taxes, Net of Federal Impact (4.6) 37.5 8.9 (1.2) 36.0 9.8 2.5 35.7 9.8 Tax Asset Valuation 36.7 — — 30.7 — — 24.5 — — Excess Stock Benefit (1.5) (1.4) (0.5) (2.3) (2.3) (0.8) (0.5) (0.5) (0.2) EDIT Amortization (9.8) (43.2) (10.5) (9.0) (20.4) (15.4) (5.8) (22.9) (4.0) Other, Net 5.6 2.4 1.8 4.2 2.9 1.9 2.3 1.6 (0.6) Income Tax Expense $ 131.3 $ 114.3 $ 39.4 $ 149.7 $ 130.8 $ 31.7 $ 137.0 $ 125.3 $ 41.0 Effective Tax Rate 24.6 % 19.3 % 20.8 % 24.6 % 22.7 % 17.7 % 25.0 % 22.5 % 23.4 %
Schedule of Accumulated Deferred Income Tax Obligations	The tax effects of temporary differences that give rise to the net accumulated deferred income tax obligations are as follows: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Eversource CL&P NSTAR PSNH Deferred Tax Assets: Employee Benefits $ 270.8 $ 23.9 $ 40.3 $ 14.1 $ 602.4 $ 144.5 $ 79.8 $ 56.6 Derivative Liabilities 76.8 76.8 — — 92.6 91.8 — — Regulatory Deferrals - Liabilities 390.7 90.9 215.4 24.3 259.8 30.2 161.8 13.4 Allowance for Uncollectible Accounts 104.1 48.8 21.5 6.2 87.5 42.3 20.9 4.6 Tax Effect - Tax Regulatory Liabilities 783.4 328.2 254.3 100.9 810.9 331.4 271.8 105.2 Net Operating Loss Carryforwards 7.5 — — — 12.7 — — — Purchase Accounting Adjustment 67.2 — — — 54.5 — — — Other 196.6 103.9 21.7 22.9 200.3 100.9 14.3 19.8 Total Deferred Tax Assets 1,897.1 672.5 553.2 168.4 2,120.7 741.1 548.6 199.6 Less: Valuation Allowance 61.5 44.5 — — 48.3 33.7 — — Net Deferred Tax Assets $ 1,835.6 $ 628.0 $ 553.2 $ 168.4 $ 2,072.4 $ 707.4 $ 548.6 $ 199.6 Deferred Tax Liabilities: Accelerated Depreciation and Other $ 4,426.0 $ 1,509.5 $ 1,553.7 $ 482.9 $ 4,153.6 $ 1,438.1 $ 1,489.4 $ 453.8 Property Tax Accruals 88.1 40.5 33.7 6.3 88.7 39.0 37.0 5.8 Regulatory Amounts: Regulatory Deferrals - Assets 1,260.3 438.3 337.6 198.4 1,376.7 444.8 324.4 263.4 Tax Effect - Tax Regulatory Assets 257.8 181.4 10.9 8.3 244.6 174.4 11.3 8.6 Goodwill Regulatory Asset - 1999 Merger 81.4 — 69.9 — 86.0 — 73.8 — Derivative Assets 14.9 14.9 — — 17.8 17.8 — — Other 304.2 5.5 126.9 10.5 200.3 1.6 72.6 5.6 Total Deferred Tax Liabilities $ 6,432.7 $ 2,190.1 $ 2,132.7 $ 706.4 $ 6,167.7 $ 2,115.7 $ 2,008.5 $ 737.2
Summary of Tax Credits and Loss Carryforwards	The following table provides the amounts and expiration dates of state tax credit and loss carryforwards and federal tax credit and net operating loss carryforwards: As of December 31, 2021 2020 (Millions of Dollars) Eversource CL&P NSTAR PSNH Expiration Range Eversource CL&P NSTAR PSNH Expiration Range State Net Operating Loss $ 138.3 $ — $ — $ — 2021 - 2040 $ 183.4 $ — $ — $ — 2021 - 2040 State Tax Credit 197.7 137.0 — — 2021 - 2026 186.6 133.4 — — 2020 - 2025 State Charitable Contribution 23.7 — — — 2021 - 2025 10.2 — — — 2020 - 2024
Summary of Income Tax Contingencies	A reconciliation of the activity in unrecognized tax benefits, all of which would impact the effective tax rate if recognized, is as follows: (Millions of Dollars) Eversource CL&P Balance as of January 1, 2019 $ 45.9 $ 18.2 Gross Increases - Current Year 12.1 4.0 Gross Increases - Prior Year 3.4 3.3 Lapse of Statute of Limitations (6.4) (2.4) Balance as of December 31, 2019 55.0 23.1 Gross Increases - Current Year 11.9 4.6 Gross Increases - Prior Year 1.4 0.7 Lapse of Statute of Limitations (6.5) (2.6) Balance as of December 31, 2020 61.8 25.8 Gross Increases - Current Year 11.3 3.8 Gross Decreases - Prior Year (0.3) (0.6) Lapse of Statute of Limitations (7.0) (2.8) Balance as of December 31, 2021 $ 65.8 $ 26.2
Summary of Income Tax Examinations	The following table summarizes Eversource, CL&P, NSTAR Electric, and PSNH's tax years that remain subject to examination by major tax jurisdictions as of December 31, 2021: Description Tax Years Federal 2021 Connecticut 2018 - 2021 Massachusetts 2018 - 2021 New Hampshire 2018 - 2021

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Environmental Loss Contingencies by Site	A reconciliation of the activity in the environmental reserves is as follows: (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Balance as of January 1, 2020 $ 81.0 $ 11.4 $ 8.0 $ 7.5 Increase Due to CMA Asset Acquisition 22.9 — — — Additions 8.4 4.2 0.7 — Payments/Reductions (9.9) (3.3) (4.0) (0.4) Balance as of December 31, 2020 102.4 12.3 4.7 7.1 Additions 23.4 4.4 — — Payments/Reductions (10.4) (2.8) (1.4) (0.8) Balance as of December 31, 2021 $ 115.4 $ 13.9 $ 3.3 $ 6.3 The number of environmental sites for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: Eversource CL&P NSTAR Electric PSNH 2021 61 14 11 9 2020 63 15 12 9
Schedule of Estimated Future Annual Costs of Long term Contractual Agreement	The estimated future annual costs of significant executed, non-cancelable, long-term contractual arrangements in effect as of December 31, 2021 are as follows: Eversource (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 755.4 $ 700.7 $ 696.4 $ 718.7 $ 714.3 $ 3,571.4 $ 7,156.9 Natural Gas Procurement 377.9 323.6 270.5 265.5 250.4 1,517.2 3,005.1 Purchased Power and Capacity 76.0 87.1 86.7 75.1 2.9 9.8 337.6 Peaker CfDs 26.1 38.9 39.4 36.7 29.9 63.3 234.3 Transmission Support Commitments 16.0 17.8 20.6 22.4 22.6 22.6 122.0 Total $ 1,251.4 $ 1,168.1 $ 1,113.6 $ 1,118.4 $ 1,020.1 $ 5,184.3 $ 10,855.9 CL&P (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 586.2 $ 592.1 $ 592.0 $ 593.9 $ 591.9 $ 2,752.2 $ 5,708.3 Purchased Power and Capacity 72.1 83.4 83.8 72.3 0.1 — 311.7 Peaker CfDs 26.1 38.9 39.4 36.7 29.9 63.3 234.3 Transmission Support Commitments 6.3 7.0 8.1 8.8 8.9 8.9 48.0 Total $ 690.7 $ 721.4 $ 723.3 $ 711.7 $ 630.8 $ 2,824.4 $ 6,302.3 NSTAR Electric (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 102.9 $ 78.3 $ 75.7 $ 76.1 $ 76.4 $ 492.3 $ 901.7 Purchased Power and Capacity 3.0 2.9 2.9 2.8 2.8 9.8 24.2 Transmission Support Commitments 6.3 7.0 8.1 8.9 8.9 8.9 48.1 Total $ 112.2 $ 88.2 $ 86.7 $ 87.8 $ 88.1 $ 511.0 $ 974.0 PSNH (Millions of Dollars) 2022 2023 2024 2025 2026 Thereafter Total Renewable Energy $ 66.3 $ 30.3 $ 28.7 $ 48.7 $ 46.0 $ 326.9 $ 546.9 Purchased Power and Capacity 0.9 0.8 — — — — 1.7 Transmission Support Commitments 3.4 3.8 4.4 4.7 4.8 4.8 25.9 Total $ 70.6 $ 34.9 $ 33.1 $ 53.4 $ 50.8 $ 331.7 $ 574.5 The total costs incurred under these agreements were as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Renewable Energy $ 609.2 $ 584.2 $ 320.8 Natural Gas Procurement 712.7 453.4 448.5 Purchased Power and Capacity 56.4 62.7 62.1 Peaker CfDs 24.3 22.7 13.0 Transmission Support Commitments 15.4 22.1 21.8 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Renewable Energy $ 457.1 $ 84.7 $ 67.4 $ 426.3 $ 88.8 $ 69.1 $ 160.6 $ 89.9 $ 70.3 Purchased Power and Capacity 53.1 3.0 0.3 59.3 3.1 0.3 50.4 5.1 6.6 Peaker CfDs 24.3 — — 22.7 — — 13.0 — — Transmission Support Commitments 6.1 6.0 3.3 8.7 8.7 4.7 8.6 8.6 4.6
Schedule of Guarantor Obligations	The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries and affiliates to external parties: As of December 31, 2021 Company (Obligor) Description Maximum Exposure Expiration Dates North East Offshore LLC Construction-related purchase agreements with third-party contractors (1) $ 1,080.6 (1) Sunrise Wind LLC Construction-related purchase agreements with third-party contractors (2) 382.3 2026 Revolution Wind, LLC Construction-related purchase agreements with third-party contractors (3) 150.9 2027 South Fork Wind, LLC Construction-related purchase agreements with third-party contractors (4) 125.2 2023 - 2026 Eversource Investment LLC Funding and indemnification obligations of North East Offshore LLC (5) — (5) Sunrise Wind LLC OREC capacity production (6) 2.2 (6) Bay State Wind LLC Real estate purchase 2.5 2022 South Fork Wind, LLC Transmission interconnection 1.2 — Various Surety bonds (7) 54.7 2022 - 2023 Eversource Service Lease payments for real estate 0.8 2024 (1) Eversource parent issued guarantees on behalf of its 50 percent-owned affiliate, North East Offshore LLC (NEO), under which Eversource parent agreed to guarantee 50 percent of NEO’s performance of obligations under certain purchase agreements with third-party contactors, in an aggregate amount not to exceed $1.3 billion with an expiration date in 2025. Eversource parent also issued a separate guarantee to Ørsted on behalf of NEO, under which Eversource parent agreed to guarantee 50 percent of NEO’s payment obligations under certain offshore wind project construction-related agreements with Ørsted in an aggregate amount not to exceed $62.5 million and expiring upon full performance of the guaranteed obligation. Any amounts paid under this guarantee to Ørsted will count toward, but not increase, the maximum amount of the Funding Guarantee described in Note 5, below. The guarantee expires upon the full performance of the guaranteed obligations. (2) Eversource parent issued a guaranty on behalf of its 50 percent-owned affiliate, Sunrise Wind LLC, whereby Eversource parent will guarantee Sunrise Wind LLC's performance of certain obligations, in an aggregate amount not to exceed $420.6 million, in connection with a construction-related purchase agreement. Eversource parent’s obligations under the guarantee expire upon the earlier of (i) April 2026 and (ii) full performance of the guaranteed obligations. (3) Eversource parent issued a guaranty on behalf of its 50 percent-owned affiliate, Revolution Wind, LLC, whereby Eversource parent will guarantee Revolution Wind, LLC's performance of certain obligations, in an aggregate amount not to exceed $158.9 million, in connection with a construction-related purchase agreement. Eversource parent’s obligations under the guarantee expire upon the earlier of (i) November 2027 and (ii) full performance of the guaranteed obligations. (4) Eversource parent issued three guarantees on behalf of its 50 percent-owned affiliate, South Fork Wind, LLC, whereby Eversource parent will guarantee South Fork Wind, LLC's performance of certain obligations in connection with three construction-related purchase agreements. Under these guarantees, Eversource parent will guarantee South Fork Wind, LLC's performance of certain obligations, in a total aggregate amount not to exceed $137.2 million. Eversource parent’s obligations under these guarantees expire upon the earlier of (i) dates ranging from October 2023 and August 2026 and (ii) full performance of the guaranteed obligations. (5) Eversource parent issued a guarantee (Funding Guarantee) on behalf of Eversource Investment LLC (EI), its wholly-owned subsidiary that holds a 50 percent ownership interest in NEO, under which Eversource parent agreed to guarantee certain funding obligations and certain indemnification payments of EI under the Amended and Restated Limited Liability Company Operating Agreement of NEO, in an amount not to exceed $910 million. The guaranteed obligations include payment of EI's funding obligations during the construction phase of NEO’s underlying offshore wind projects and indemnification obligations associated with third party credit support for its investment in NEO. Eversource parent’s obligations under the Funding Guarantee expire upon the full performance of the guaranteed obligations. (6) Eversource parent issued a guarantee on behalf of its 50 percent-owned affiliate, Sunrise Wind LLC, whereby Eversource parent will guarantee 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. The guarantee expires upon the full performance of the guaranteed obligations.

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Components of Lease Cost	The components of lease cost, prior to amounts capitalized, are as follows: Eversource For the Years Ended December 31, (Millions of Dollars) 2021 2020 2019 Finance Lease Cost: Amortization of Right-of-use-Assets $ 4.6 $ 2.6 $ 1.7 Interest on Lease Liabilities 3.9 1.4 1.2 Total Finance Lease Cost 8.5 4.0 2.9 Operating Lease Cost 12.2 11.1 11.7 Variable Lease Cost 61.0 57.8 60.5 Total Lease Cost $ 81.7 $ 72.9 $ 75.1 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR PSNH CL&P NSTAR PSNH CL&P NSTAR PSNH Finance Lease Cost: Amortization of Right-of-use-Assets $ 0.5 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 $ 0.7 $ 0.2 $ 0.1 Interest on Lease Liabilities 0.1 0.6 — 0.3 0.6 — 0.6 0.6 — Total Finance Lease Cost 0.6 0.8 0.1 1.0 0.8 0.1 1.3 0.8 0.1 Operating Lease Cost 0.3 2.3 0.1 0.6 2.1 0.1 0.5 3.4 0.1 Variable Lease Cost 16.2 — 44.8 12.2 — 45.6 13.3 — 47.2 Total Lease Cost $ 17.1 $ 3.1 $ 45.0 $ 13.8 $ 2.9 $ 45.8 $ 15.1 $ 4.2 $ 47.4
Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases is as follows: As of December 31, 2021 As of December 31, 2020 (Millions of Dollars) Balance Sheet Classification Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Operating Leases: Right-of-use-Assets, Net Other Long-Term Assets $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Operating Lease Liabilities Current Portion Other Current Liabilities $ 10.0 $ 0.1 $ 1.1 $ — $ 9.5 $ 0.2 $ 0.7 $ — Long-Term Other Long-Term Liabilities 37.2 — 23.2 0.3 45.7 0.1 22.9 0.3 Total Operating Lease Liabilities $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 55.2 $ 0.3 $ 23.6 $ 0.3 Finance Leases: Right-of-use-Assets, Net Property, Plant and Equipment, Net $ 58.0 $ — $ 3.3 $ 0.7 $ 60.5 $ 0.7 $ 3.5 $ 0.8 Finance Lease Liabilities Current Portion Other Current Liabilities $ 3.9 $ — $ — $ 0.1 $ 5.0 $ 1.4 $ — $ 0.1 Long-Term Other Long-Term Liabilities 55.4 — 4.9 0.6 57.6 — 4.8 0.7 Total Finance Lease Liabilities $ 59.3 $ — $ 4.9 $ 0.7 $ 62.6 $ 1.4 $ 4.8 $ 0.8
Other Information Related to Leases	Other information related to leases is as follows: As of December 31, 2021 2020 Eversource CL&P NSTAR Electric PSNH Eversource CL&P NSTAR Electric PSNH Weighted-Average Remaining Lease Term (Years): Operating Leases 13 7 18 7 10 3 19 8 Finance Leases 16 — 20 7 17 1 21 8 Weighted-Average Discount Rate (Percentage): Operating Leases 4.1 % 3.0 % 4.0 % 3.7 % 4.0 % 2.4 % 4.1 % 3.7 % Finance Leases 2.7 % — % 2.9 % 3.5 % 2.9 % 10.5 % 2.9 % 3.5 % (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2021 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 12.1 $ 0.3 $ 2.1 $ 0.1 Operating Cash Flows from Finance Leases 3.4 0.1 0.6 — Financing Cash Flows from Finance Leases 4.1 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.1 — 1.9 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.3 — — — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2020 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 10.9 $ 0.6 $ 1.8 $ 0.1 Operating Cash Flows from Finance Leases 1.7 0.3 0.6 — Financing Cash Flows from Finance Leases 2.8 1.6 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 0.6 0.1 0.2 — Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 0.7 — 0.3 — (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH For the Year Ended December 31, 2019 Cash Paid for Amounts Included in the Measurement of Lease Liabilities: Operating Cash Flows from Operating Leases $ 11.4 $ 0.4 $ 1.6 $ 0.1 Operating Cash Flows from Finance Leases 1.2 0.6 0.6 — Financing Cash Flows from Finance Leases 2.6 1.4 — 0.1 Supplemental Non-Cash Information on Lease Liabilities: Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities 2.9 1.0 0.1 0.2 Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities 2.0 — — —
Future Minimum Lease Payments under Long-Term Finance Leases	Future minimum lease payments, excluding variable costs, under long-term leases, as of December 31, 2021 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource NSTAR Electric PSNH Year Ending December 31, 2022 $ 11.1 $ 0.1 $ 2.1 $ 0.1 $ 6.0 $ 0.6 $ 0.1 2023 7.6 — 2.1 0.1 5.2 0.7 0.1 2024 6.1 — 2.1 — 5.3 0.7 0.1 2025 3.2 — 1.7 — 5.2 0.6 0.1 2026 2.5 — 1.7 — 4.7 0.6 0.1 Thereafter 27.8 — 25.3 0.1 56.0 12.4 0.3 Future lease payments 58.3 0.1 35.0 0.3 82.4 15.6 0.8 Less amount representing interest 11.1 — 10.7 — 23.1 10.7 0.1 Present value of future minimum lease payments $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 59.3 $ 4.9 $ 0.7
Future Minimum Lease Payments under Long-Term Operating Leases	Future minimum lease payments, excluding variable costs, under long-term leases, as of December 31, 2021 are as follows: Operating Leases Finance Leases (Millions of Dollars) Eversource CL&P NSTAR Electric PSNH Eversource NSTAR Electric PSNH Year Ending December 31, 2022 $ 11.1 $ 0.1 $ 2.1 $ 0.1 $ 6.0 $ 0.6 $ 0.1 2023 7.6 — 2.1 0.1 5.2 0.7 0.1 2024 6.1 — 2.1 — 5.3 0.7 0.1 2025 3.2 — 1.7 — 5.2 0.6 0.1 2026 2.5 — 1.7 — 4.7 0.6 0.1 Thereafter 27.8 — 25.3 0.1 56.0 12.4 0.3 Future lease payments 58.3 0.1 35.0 0.3 82.4 15.6 0.8 Less amount representing interest 11.1 — 10.7 — 23.1 10.7 0.1 Present value of future minimum lease payments $ 47.2 $ 0.1 $ 24.3 $ 0.3 $ 59.3 $ 4.9 $ 0.7

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Carrying Amounts and Estimated Fair Values of Financial Instruments	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 Fair Carrying Fair Carrying Fair As of December 31, 2021: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 166.3 $ 116.2 $ 122.3 $ 43.0 $ 44.0 $ — $ — Long-Term Debt 18,216.7 19,636.3 4,215.4 4,848.9 3,985.4 4,453.5 1,163.8 1,220.6 Rate Reduction Bonds 496.9 543.3 — — — — 496.9 543.3 As of December 31, 2020: Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 169.1 $ 116.2 $ 123.4 $ 43.0 $ 45.7 $ — $ — Long-Term Debt 16,179.1 18,420.1 3,914.8 4,800.9 3,643.2 4,294.0 1,099.1 1,207.0 Rate Reduction Bonds 540.1 603.4 — — — — 540.1 603.4

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Tables)	12 Months Ended
	Dec. 31, 2021
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 Year Ended December 31, 2021 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Qualified Unrealized Defined Total Qualified Unrealized Defined Total Balance as of January 1st $ (1.4) $ 1.1 $ (76.1) $ (76.4) $ (3.0) $ 0.7 $ (62.8) $ (65.1) OCI Before Reclassifications — (0.7) 24.1 23.4 — 0.4 (19.6) (19.2) Amounts Reclassified from AOCI 1.0 — 9.7 10.7 1.6 — 6.3 7.9 Net OCI 1.0 (0.7) 33.8 34.1 1.6 0.4 (13.3) (11.3) Balance as of December 31st $ (0.4) $ 0.4 $ (42.3) $ (42.3) $ (1.4) $ 1.1 $ (76.1) $ (76.4)
Schedule of Amounts Reclassified from AOCI by Component	The following table sets forth the amounts reclassified from AOCI by component and the impacted line item on the statements of income: Amounts Reclassified from AOCI Eversource (Millions of Dollars) For the Years Ended December 31, Statements of Income 2021 2020 2019 Qualified Cash Flow Hedging Instruments $ (1.7) $ (2.5) $ (2.5) Interest Expense Tax Effect 0.7 0.9 1.1 Income Tax Expense Qualified Cash Flow Hedging Instruments, Net of Tax $ (1.0) $ (1.6) $ (1.4) Defined Benefit Plan Costs: Amortization of Actuarial Losses $ (13.1) $ (8.1) $ (5.7) Other Income, Net (1) Amortization of Prior Service Credit/(Cost) — (0.3) (1.8) Other Income, Net (1) Total Defined Benefit Plan Costs (13.1) (8.4) (7.5) Tax Effect 3.4 2.1 1.9 Income Tax Expense Defined Benefit Plan Costs, Net of Tax $ (9.7) $ (6.3) $ (5.6) Total Amounts Reclassified from AOCI, Net of Tax $ (10.7) $ (7.9) $ (7.0) (1) These amounts are included in the computation of net periodic Pension, SERP and PBOP costs. See Note 1M, "Summary of Significant Accounting Policies – Other Income, Net" and Note 11A, "Employee Benefits – Pension Benefits and Postretirement Benefits Other Than Pension," for further information.

COMMON SHARES (Tables)

COMMON SHARES (Tables)	12 Months Ended
	Dec. 31, 2021
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 Par Value Authorized as of December 31, 2021 and 2020 Issued as of December 31, 2021 2020 Eversource $ 5 380,000,000 357,818,402 357,818,402 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 Details of preferred stock not subject to mandatory redemption are as follows (in millions, except in redemption price and shares): Redemption Price Shares Outstanding as of December 31, As of December 31, Series 2021 2020 2021 2020 CL&P $1.90 Series of 1947 $ 52.50 163,912 163,912 $ 8.2 $ 8.2 $2.00 Series of 1947 $ 54.00 336,088 336,088 16.8 16.8 $2.04 Series of 1949 $ 52.00 100,000 100,000 5.0 5.0 $2.20 Series of 1949 $ 52.50 200,000 200,000 10.0 10.0 3.90% Series of 1949 $ 50.50 160,000 160,000 8.0 8.0 $2.06 Series E of 1954 $ 51.00 200,000 200,000 10.0 10.0 $2.09 Series F of 1955 $ 51.00 100,000 100,000 5.0 5.0 4.50% Series of 1956 $ 50.75 104,000 104,000 5.2 5.2 4.96% Series of 1958 $ 50.50 100,000 100,000 5.0 5.0 4.50% Series of 1963 $ 50.50 160,000 160,000 8.0 8.0 5.28% Series of 1967 $ 51.43 200,000 200,000 10.0 10.0 $3.24 Series G of 1968 $ 51.84 300,000 300,000 15.0 15.0 6.56% Series of 1968 $ 51.44 200,000 200,000 10.0 10.0 Total CL&P 2,324,000 2,324,000 $ 116.2 $ 116.2 NSTAR Electric 4.25% Series of 1956 $ 103.625 180,000 180,000 $ 18.0 $ 18.0 4.78% Series of 1958 $ 102.80 250,000 250,000 25.0 25.0 Total NSTAR Electric 430,000 430,000 $ 43.0 $ 43.0 Fair Value Adjustment due to Merger with NSTAR (3.6) (3.6) Other 6.00% Series of 1958 $ 100.00 23 23 $ — $ — Total Eversource - Noncontrolling Interest - Preferred Stock of Subsidiaries $ 155.6 $ 155.6

PREFERRED STOCK NOT SUBJECT T_2

PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Preferred Stock Not Subject to Mandatory Redemption	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 Par Value Authorized as of December 31, 2021 and 2020 Issued as of December 31, 2021 2020 Eversource $ 5 380,000,000 357,818,402 357,818,402 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 Details of preferred stock not subject to mandatory redemption are as follows (in millions, except in redemption price and shares): Redemption Price Shares Outstanding as of December 31, As of December 31, Series 2021 2020 2021 2020 CL&P $1.90 Series of 1947 $ 52.50 163,912 163,912 $ 8.2 $ 8.2 $2.00 Series of 1947 $ 54.00 336,088 336,088 16.8 16.8 $2.04 Series of 1949 $ 52.00 100,000 100,000 5.0 5.0 $2.20 Series of 1949 $ 52.50 200,000 200,000 10.0 10.0 3.90% Series of 1949 $ 50.50 160,000 160,000 8.0 8.0 $2.06 Series E of 1954 $ 51.00 200,000 200,000 10.0 10.0 $2.09 Series F of 1955 $ 51.00 100,000 100,000 5.0 5.0 4.50% Series of 1956 $ 50.75 104,000 104,000 5.2 5.2 4.96% Series of 1958 $ 50.50 100,000 100,000 5.0 5.0 4.50% Series of 1963 $ 50.50 160,000 160,000 8.0 8.0 5.28% Series of 1967 $ 51.43 200,000 200,000 10.0 10.0 $3.24 Series G of 1968 $ 51.84 300,000 300,000 15.0 15.0 6.56% Series of 1968 $ 51.44 200,000 200,000 10.0 10.0 Total CL&P 2,324,000 2,324,000 $ 116.2 $ 116.2 NSTAR Electric 4.25% Series of 1956 $ 103.625 180,000 180,000 $ 18.0 $ 18.0 4.78% Series of 1958 $ 102.80 250,000 250,000 25.0 25.0 Total NSTAR Electric 430,000 430,000 $ 43.0 $ 43.0 Fair Value Adjustment due to Merger with NSTAR (3.6) (3.6) Other 6.00% Series of 1958 $ 100.00 23 23 $ — $ — Total Eversource - Noncontrolling Interest - Preferred Stock of Subsidiaries $ 155.6 $ 155.6

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
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 Years Ended December 31, 2021 2020 2019 Net Income Attributable to Common Shareholders $ 1,220.5 $ 1,205.2 $ 909.1 Weighted Average Common Shares Outstanding: Basic 343,972,926 338,836,147 321,416,086 Dilutive Effect of: Share-Based Compensation Awards and Other 658,130 738,994 762,215 Equity Forward Sale Agreement — 271,921 763,335 Total Dilutive Effect 658,130 1,010,915 1,525,550 Diluted 344,631,056 339,847,062 322,941,636 Basic EPS $ 3.55 $ 3.56 $ 2.83 Diluted EPS $ 3.54 $ 3.55 $ 2.81

REVENUES (Tables)

REVENUES (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following tables present operating revenues disaggregated by revenue source: For the Year Ended December 31, 2021 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,989.8 $ 1,000.3 $ — $ 133.5 $ — $ — $ 5,123.6 Commercial 2,486.1 497.6 — 62.8 — (5.1) 3,041.4 Industrial 345.3 167.2 — 4.3 — (17.1) 499.7 Total Retail Tariff Sales Revenues 6,821.2 1,665.1 — 200.6 — (22.2) 8,664.7 Wholesale Transmission Revenues — — 1,751.3 — 86.6 (1,384.7) 453.2 Wholesale Market Sales Revenues 575.8 82.1 — 3.9 — — 661.8 Other Revenues from Contracts with Customers 78.1 5.1 13.6 7.5 1,267.4 (1,257.7) 114.0 Reserve for Revenues Subject to Refund (71.1) — (5.0) (2.6) — — (78.7) Total Revenues from Contracts with Customers 7,404.0 1,752.3 1,759.9 209.4 1,354.0 (2,664.6) 9,815.0 Alternative Revenue Programs 14.7 37.0 (126.1) 1.5 — 114.6 41.7 Other Revenues 4.9 0.3 0.8 0.4 — — 6.4 Total Operating Revenues $ 7,423.6 $ 1,789.6 $ 1,634.6 $ 211.3 $ 1,354.0 $ (2,550.0) $ 9,863.1 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,951.5 $ 644.9 $ — $ 145.1 $ — $ — $ 4,741.5 Commercial 2,353.4 361.9 — 62.4 — (4.8) 2,772.9 Industrial 327.1 107.4 — 4.8 — (13.7) 425.6 Total Retail Tariff Sales Revenues 6,632.0 1,114.2 — 212.3 — (18.5) 7,940.0 Wholesale Transmission Revenues — — 1,557.3 — 74.2 (1,290.6) 340.9 Wholesale Market Sales Revenues 327.3 43.0 — 3.8 — — 374.1 Other Revenues from Contracts with Customers 79.3 5.7 13.3 3.5 1,161.7 (1,152.0) 111.5 Total Revenues from Contracts with Customers 7,038.6 1,162.9 1,570.6 219.6 1,235.9 (2,461.1) 8,766.5 Alternative Revenue Programs 88.1 44.7 (35.2) (4.7) — 37.1 130.0 Other Revenues 5.6 1.1 0.7 0.5 — — 7.9 Total Operating Revenues $ 7,132.3 $ 1,208.7 $ 1,536.1 $ 215.4 $ 1,235.9 $ (2,424.0) $ 8,904.4 For the Year Ended December 31, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Revenues from Contracts with Customers Retail Tariff Sales Residential $ 3,723.7 $ 555.1 $ — $ 132.3 $ — $ — $ 4,411.1 Commercial 2,584.8 347.6 — 63.9 — (4.3) 2,992.0 Industrial 331.8 96.9 — 4.5 — (11.6) 421.6 Total Retail Tariff Sales Revenues 6,640.3 999.6 — 200.7 — (15.9) 7,824.7 Wholesale Transmission Revenues — — 1,293.3 — 61.3 (1,085.2) 269.4 Wholesale Market Sales Revenues 215.7 55.4 — 4.1 — — 275.2 Other Revenues from Contracts with Customers 56.1 9.0 13.2 4.2 967.2 (969.0) 80.7 Total Revenues from Contracts with Customers 6,912.1 1,064.0 1,306.5 209.0 1,028.5 (2,070.1) 8,450.0 Alternative Revenue Programs 45.9 (4.9) 81.8 4.6 — (74.2) 53.2 Other Revenues 18.5 3.1 0.7 1.0 — — 23.3 Total Operating Revenues $ 6,976.5 $ 1,062.2 $ 1,389.0 $ 214.6 $ 1,028.5 $ (2,144.3) $ 8,526.5 For the Years Ended December 31, 2021 2020 2019 (Millions of Dollars) CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH CL&P NSTAR Electric PSNH Revenues from Contracts with Customers Retail Tariff Sales Residential $ 1,994.2 $ 1,375.8 $ 619.8 $ 2,011.1 $ 1,365.8 $ 574.6 $ 1,837.1 $ 1,322.1 $ 564.5 Commercial 890.6 1,265.0 332.2 878.3 1,176.8 299.9 922.9 1,349.4 314.6 Industrial 131.4 119.1 94.8 137.5 106.4 83.2 138.3 115.8 77.7 Total Retail Tariff Sales Revenues 3,016.2 2,759.9 1,046.8 3,026.9 2,649.0 957.7 2,898.3 2,787.3 956.8 Wholesale Transmission Revenues 863.3 616.3 271.7 754.8 576.5 226.0 587.1 517.3 188.9 Wholesale Market Sales Revenues 408.8 109.2 57.8 230.1 58.4 38.8 105.1 73.1 37.5 Other Revenues from Contracts 26.7 56.2 11.3 32.9 43.6 14.2 36.4 18.7 15.6 (Reserve for)/Amortization of Revenues (76.1) — — — — 4.6 — — 1.3 Total Revenues from Contracts 4,238.9 3,541.6 1,387.6 4,044.7 3,327.5 1,241.3 3,626.9 3,396.4 1,200.1 Alternative Revenue Programs (78.9) (15.1) (17.4) (4.2) 54.5 2.6 77.5 41.6 8.6 Other Revenues 0.4 3.4 1.9 2.2 3.5 0.6 10.3 7.0 1.9 Eliminations (523.0) (473.5) (194.9) (495.2) (444.4) (165.4) (482.1) (400.4) (144.7) Total Operating Revenues $ 3,637.4 $ 3,056.4 $ 1,177.2 $ 3,547.5 $ 2,941.1 $ 1,079.1 $ 3,232.6 $ 3,044.6 $ 1,065.9

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Summary of Segment Information and Segmented Total Assets	Eversource's segment information is as follows: For the Year Ended December 31, 2021 Eversource (Millions of Dollars) Electric Natural Gas Electric Transmission Water Distribution Other Eliminations Total Operating Revenues $ 7,423.6 $ 1,789.6 $ 1,634.6 $ 211.3 $ 1,354.0 $ (2,550.0) $ 9,863.1 Depreciation and Amortization (737.8) (142.3) (300.3) (46.1) (113.1) 4.6 (1,335.0) Other Operating Expenses (5,970.0) (1,345.4) (496.2) (101.4) (1,170.4) 2,548.6 (6,534.8) Operating Income 715.8 301.9 838.1 63.8 70.5 3.2 1,993.3 Interest Expense (236.4) (58.6) (133.2) (32.0) (168.8) 46.6 (582.4) Interest Income 20.7 4.5 2.2 — 46.0 (47.8) 25.6 Other Income, Net 78.1 17.9 19.8 3.3 1,363.9 (1,347.3) 135.7 Income Tax (Expense)/Benefit (103.5) (60.9) (179.4) 1.7 (2.1) — (344.2) Net Income 474.7 204.8 547.5 36.8 1,309.5 (1,345.3) 1,228.0 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 470.1 $ 204.8 $ 544.6 $ 36.8 $ 1,309.5 $ (1,345.3) $ 1,220.5 Total Assets (as of) $ 25,411.2 $ 7,215.9 $ 12,377.8 $ 2,551.1 $ 22,674.7 $ (21,738.6) $ 48,492.1 Cash Flows Used for Investments in Plant $ 1,053.3 $ 721.1 $ 1,024.1 $ 137.2 $ 239.4 $ — $ 3,175.1 For the Year Ended December 31, 2020 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Operating Revenues $ 7,132.3 $ 1,208.7 $ 1,536.1 $ 215.4 $ 1,235.9 $ (2,424.0) $ 8,904.4 Depreciation and Amortization (657.0) (87.9) (278.1) (44.2) (93.5) 1.6 (1,159.1) Other Operating Expenses (5,642.3) (913.8) (470.0) (86.6) (1,071.9) 2,428.0 (5,756.6) Operating Income 833.0 207.0 788.0 84.6 70.5 5.6 1,988.7 Interest Expense (216.0) (40.0) (126.8) (32.9) (161.0) 38.3 (538.4) Interest Income 3.2 0.9 4.7 — 37.8 (41.8) 4.8 Other Income, Net 58.0 3.1 23.3 2.0 1,382.9 (1,365.5) 103.8 Income Tax (Expense)/Benefit (129.6) (36.9) (183.8) (12.5) 16.6 — (346.2) Net Income 548.6 134.1 505.4 41.2 1,346.8 (1,363.4) 1,212.7 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 544.0 $ 134.1 $ 502.5 $ 41.2 $ 1,346.8 $ (1,363.4) $ 1,205.2 Total Assets (as of) $ 24,981.9 $ 6,450.5 $ 11,695.0 $ 2,375.2 $ 22,089.4 $ (21,492.4) $ 46,099.6 Cash Flows Used for Investments in Plant $ 1,079.0 $ 494.4 $ 1,004.6 $ 118.8 $ 246.2 $ — $ 2,943.0 For the Year Ended December 31, 2019 Eversource (Millions of Dollars) Electric Natural Gas Electric Water Distribution Other Eliminations Total Operating Revenues $ 6,976.5 $ 1,062.2 $ 1,389.0 $ 214.6 $ 1,028.5 $ (2,144.3) $ 8,526.5 Depreciation and Amortization (651.3) (68.3) (253.3) (46.9) (63.2) 2.3 (1,080.7) Impairment of Northern Pass Transmission — — (239.6) — — — (239.6) Other Operating Expenses (5,525.1) (830.8) (411.2) (101.0) (891.3) 2,143.7 (5,615.7) Operating Income 800.1 163.1 484.9 66.7 74.0 1.7 1,590.5 Interest Expense (206.4) (47.4) (125.7) (34.6) (170.3) 51.2 (533.2) Interest Income 13.3 0.1 1.5 — 48.7 (50.8) 12.8 Other Income, Net 46.8 1.6 29.2 0.4 945.3 (903.3) 120.0 Income Tax (Expense)/Benefit (135.9) (21.2) (130.5) 2.4 11.7 — (273.5) Net Income 517.9 96.2 259.4 34.9 909.4 (901.2) 916.6 Net Income Attributable to Noncontrolling Interests (4.6) — (2.9) — — — (7.5) Net Income Attributable to Common Shareholders $ 513.3 $ 96.2 $ 256.5 $ 34.9 $ 909.4 $ (901.2) $ 909.1 Cash Flows Used for Investments in Plant $ 1,104.2 $ 460.2 $ 987.0 $ 118.0 $ 242.1 $ — $ 2,911.5

ACQUISITION OF ASSETS OF COLU_2

ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Preliminary Allocation of the Cash Purchase Price	The allocation of the cash purchase price as of October 9, 2020 is as follows: (Millions of Dollars) Current Assets $ 138 Restricted Cash 57 PP&E 1,182 Goodwill 52 Other Noncurrent Assets, excluding Goodwill 131 Other Current Liabilities (81) Other Noncurrent Liabilities (310) Cash Purchase Price $ 1,169
Summary of Unaudited Pro Forma Financial Information	The following unaudited pro forma financial information reflects the pro forma combined results of operations of Eversource and the CMA business acquired and reflects the amortization of purchase price adjustments assuming the acquisition had taken place on January 1, 2019. The unaudited pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of Eversource. Pro forma net income excludes the impact of assets and liabilities not assumed by Eversource, such as amounts directly associated with the GLI incident, and non-recurring costs associated with the transaction. For the Years Ended December 31, (Pro forma amounts in millions, except share amounts) 2020 2019 Operating Revenues $ 9,273 $ 9,103 Net Income Attributable to Common Shareholders 1,265 909 Basic EPS 3.73 2.83 Diluted EPS 3.72 2.82

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill by Reportable Segment	The following table presents goodwill by reportable segment: (Millions of Dollars) Electric Electric Natural Gas Water Distribution Total Balance as of January 1, 2020 $ 2,544 $ 577 $ 399 $ 907 $ 4,427 Acquisition of CMA Assets — — 42 — 42 Sale of Hingham water system — — — (23) (23) Balance as of December 31, 2020 $ 2,544 $ 577 $ 441 $ 884 $ 4,446 CMA Measurement Period Adjustments — — 10 — 10 Acquisition of NESC — — — 21 21 Balance as of December 31, 2021 $ 2,544 $ 577 $ 451 $ 905 $ 4,477

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Thousands, customer in Millions	Oct. 09, 2020USD ($)	Dec. 31, 2021USD ($)customerutilityMW	Dec. 31, 2020USD ($)MW	Dec. 31, 2019USD ($)$ / shares
Summary of Accounting Policies [Line Items]
Number of electric and natural gas customers | customer		4.4
Goodwill		$ 4,477,269	$ 4,445,988	$ 4,427,000
Amount of power to be purchased under capacity-related contract (up to) (in MW) | MW			675
Pre-tax impairment charge		0	$ 0	239,644
Allowance for uncollectible accounts for late fees and other receivable amounts		417,406	358,851	224,800
Charitable contributions			6,400
Increase to operating cash inflows in accounts payable		29,201	(122,567)	(14,866)
Increase to investing cash outflows in investments in property, plant and equipment		3,175,080	2,942,996	2,911,489
Electric Transmission
Summary of Accounting Policies [Line Items]
Goodwill		577,000	577,000	577,000
Energy Relief Fund
Summary of Accounting Policies [Line Items]
Restricted cash		$ 41,500
Northern Pass Transmission
Summary of Accounting Policies [Line Items]
Amount of power to be purchased under capacity-related contract (up to) (in MW) | MW		1,090
Pre-tax impairment charge				318,000
After-tax impact of impairment charge				$ (204,400)
After-tax impact of impairment charge (in dollars per share) | $ / shares				$ (0.64)
Northern Pass Transmission | Electric Transmission
Summary of Accounting Policies [Line Items]
Pre-tax impairment charge				$ 239,600
Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		$ 191,300	164,100	81,500
CMA
Summary of Accounting Policies [Line Items]
Purchase price	$ 1,100,000
Target working capital amount	68,600
Goodwill	$ 52,000
The Connecticut Light and Power Company
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		$ 181,319	157,447	97,300
Period of accounts receivable recoverable under financial or medical duress		180 days
Maximum loans receivable outstanding		$ 55,000
Loans transferred receivable current		10,500	12,900
Loans transferred receivable non-current		8,300	9,500
Tax remittance to state for energy efficiency funds				21,400
Long term receivable		25,000	25,000
Increase to operating cash inflows in accounts payable		(24,895)	17,028	(102,344)
Increase to investing cash outflows in investments in property, plant and equipment		790,083	833,973	917,532
The Connecticut Light and Power Company | Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		$ 36,700	28,300	17,200
Yankee Gas Services Company
Summary of Accounting Policies [Line Items]
Period of accounts receivable recoverable under financial or medical duress		90 days
NSTAR Electric Company
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		$ 97,005	91,583	75,400
Long term receivable		5,500	5,500
Increase to operating cash inflows in accounts payable		(31,650)	(25,573)	22,659
Increase to investing cash outflows in investments in property, plant and equipment		960,949	907,000	861,391
NSTAR Electric Company | Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		53,700	51,900	31,500
Public Service Company of New Hampshire
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts		24,331	17,157	10,500
Long term receivable		3,800	3,800
Increase to operating cash inflows in accounts payable		3,256	(27,270)	(12,281)
Increase to investing cash outflows in investments in property, plant and equipment		$ 326,379	342,586	308,993
Connecticut, Massachusetts and New Hampshire
Summary of Accounting Policies [Line Items]
Number of regulated utilities | utility		10
Restatement Adjustment
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts			23,800
Restatement Adjustment | Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts				2,200
Restatement Adjustment | The Connecticut Light and Power Company
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts			22,200
Restatement Adjustment | The Connecticut Light and Power Company | Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts				900
Restatement Adjustment | NSTAR Electric Company
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts			(1,300)
Restatement Adjustment | NSTAR Electric Company | Retail Non Hardship Wholesaleand Other Receivables
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts				$ 300
Restatement Adjustment | Public Service Company of New Hampshire
Summary of Accounting Policies [Line Items]
Allowance for uncollectible accounts for late fees and other receivable amounts			$ 300
COVID 19
Summary of Accounting Policies [Line Items]
Accounts receivable, allowance for uncollectible accounts increase (decrease)		$ 24,100
Allowance for uncollectible accounts for late fees and other receivable amounts		55,300
COVID 19 | The Connecticut Light and Power Company
Summary of Accounting Policies [Line Items]
Accounts receivable, allowance for uncollectible accounts increase (decrease)		20,100
Allowance for uncollectible accounts for late fees and other receivable amounts		23,900
COVID 19 | NSTAR Electric Company
Summary of Accounting Policies [Line Items]
Accounts receivable, allowance for uncollectible accounts increase (decrease)		(1,300)
Allowance for uncollectible accounts for late fees and other receivable amounts		9,000
COVID 19 | Public Service Company of New Hampshire
Summary of Accounting Policies [Line Items]
Decrease in deferral cost		600
COVID 19 | Natural Gas Businesses
Summary of Accounting Policies [Line Items]
Accounts receivable, allowance for uncollectible accounts increase (decrease)		6,600
Allowance for uncollectible accounts for late fees and other receivable amounts		$ 21,400

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Allowance for Uncollectible Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	$ 358,851	$ 224,800
Increase due to CMA acquisition		24,200
Uncollectible Expense	60,886	53,461	$ 63,446
Uncollectible Costs Deferred	110,600	97,000
Write-Offs	(129,700)	(78,000)
Recoveries Collected	16,700	13,600
Balance as of December 31, 2020	417,406	358,851	224,800
Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	23,800
Balance as of December 31, 2020		23,800
Hardship Accounts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	194,800	143,300
Increase due to CMA acquisition		0
Uncollectible Expense	0	0
Uncollectible Costs Deferred	51,900	43,100
Write-Offs	(22,000)	(14,700)
Recoveries Collected	1,400	1,500
Balance as of December 31, 2020	226,100	194,800	143,300
Hardship Accounts | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		21,600
Balance as of December 31, 2020			21,600
Retail Non Hardship Wholesaleand Other Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	164,100	81,500
Increase due to CMA acquisition		24,200
Uncollectible Expense	60,900	53,500
Uncollectible Costs Deferred	58,700	53,900
Write-Offs	(107,700)	(63,300)
Recoveries Collected	15,300	12,100
Balance as of December 31, 2020	191,300	164,100	81,500
Retail Non Hardship Wholesaleand Other Receivables | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		2,200
Balance as of December 31, 2020			2,200
The Connecticut Light and Power Company
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	157,447	97,300
Increase due to CMA acquisition		0
Uncollectible Expense	13,495	12,882	15,948
Uncollectible Costs Deferred	57,800	49,000
Write-Offs	(54,200)	(29,700)
Recoveries Collected	6,800	5,700
Balance as of December 31, 2020	181,319	157,447	97,300
The Connecticut Light and Power Company | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	22,200
Balance as of December 31, 2020		22,200
The Connecticut Light and Power Company | Hardship Accounts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	129,100	80,100
Increase due to CMA acquisition		0
Uncollectible Expense	0	0
Uncollectible Costs Deferred	32,300	38,200
Write-Offs	(18,000)	(11,900)
Recoveries Collected	1,200	1,400
Balance as of December 31, 2020	144,600	129,100	80,100
The Connecticut Light and Power Company | Hardship Accounts | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		21,300
Balance as of December 31, 2020			21,300
The Connecticut Light and Power Company | Retail Non Hardship Wholesaleand Other Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	28,300	17,200
Increase due to CMA acquisition		0
Uncollectible Expense	13,500	12,900
Uncollectible Costs Deferred	25,500	10,800
Write-Offs	(36,200)	(17,800)
Recoveries Collected	5,600	4,300
Balance as of December 31, 2020	36,700	28,300	17,200
The Connecticut Light and Power Company | Retail Non Hardship Wholesaleand Other Receivables | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		900
Balance as of December 31, 2020			900
NSTAR Electric Company
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	91,583	75,400
Increase due to CMA acquisition		0
Uncollectible Expense	16,649	15,293	25,079
Uncollectible Costs Deferred	20,100	24,700
Write-Offs	(37,000)	(27,200)
Recoveries Collected	5,700	4,700
Balance as of December 31, 2020	97,005	91,583	75,400
NSTAR Electric Company | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	(1,300)
Balance as of December 31, 2020		(1,300)
NSTAR Electric Company | Hardship Accounts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	39,700	43,900
Increase due to CMA acquisition		0
Uncollectible Expense	0	0
Uncollectible Costs Deferred	4,300	(1,700)
Write-Offs	(700)	(900)
Recoveries Collected	0	0
Balance as of December 31, 2020	43,300	39,700	43,900
NSTAR Electric Company | Hardship Accounts | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		(1,600)
Balance as of December 31, 2020			(1,600)
NSTAR Electric Company | Retail Non Hardship Wholesaleand Other Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	51,900	31,500
Increase due to CMA acquisition		0
Uncollectible Expense	16,600	15,300
Uncollectible Costs Deferred	15,800	26,400
Write-Offs	(36,300)	(26,300)
Recoveries Collected	5,700	4,700
Balance as of December 31, 2020	53,700	51,900	31,500
NSTAR Electric Company | Retail Non Hardship Wholesaleand Other Receivables | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020		300
Balance as of December 31, 2020			300
Public Service Company of New Hampshire
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	17,157	10,500
Increase due to CMA acquisition		0
Uncollectible Expense	13,113	5,164	6,726
Uncollectible Costs Deferred	3,100	7,400
Write-Offs	(10,000)	(6,900)
Recoveries Collected	900	700
Balance as of December 31, 2020	24,331	17,157	$ 10,500
Public Service Company of New Hampshire | Restatement Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of January 1, 2020	$ 300
Balance as of December 31, 2020		$ 300

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES -Transfer of Energy Efficiency Loans (Details) - The Connecticut Light and Power Company - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loans receivable outstanding	$ 55
Loans transferred receivable current	10.5	$ 12.9
Loans transferred receivable non-current	$ 8.3	$ 9.5

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fuel, Materials, Supplies and Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, Inventory [Line Items]
Total	$ 267.5	$ 265.6
Fuel
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	56.2	38.2
Materials and Supplies
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	148.9	151.3
RECs
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	62.4	76.1
The Connecticut Light and Power Company
Public Utilities, Inventory [Line Items]
Total	60.3	57.9
The Connecticut Light and Power Company | Fuel
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	0	0
The Connecticut Light and Power Company | Materials and Supplies
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	60.3	57.9
The Connecticut Light and Power Company | RECs
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	0	0
NSTAR Electric Company
Public Utilities, Inventory [Line Items]
Total	116.7	133.9
NSTAR Electric Company | Fuel
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	0	0
NSTAR Electric Company | Materials and Supplies
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	55	62.1
NSTAR Electric Company | RECs
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	61.7	71.8
Public Service Company of New Hampshire
Public Utilities, Inventory [Line Items]
Total	25.9	26.8
Public Service Company of New Hampshire | Fuel
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	0	0
Public Service Company of New Hampshire | Materials and Supplies
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	25.2	22.5
Public Service Company of New Hampshire | RECs
Public Utilities, Inventory [Line Items]
Other inventory, capitalized costs, gross	$ 0.7	$ 4.3

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Operating Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Accounting Policies [Line Items]
Natural gas and fuel costs	$ 718.6	$ 464.2	$ 462.1

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of AFUDC and Weighted Average AFUDC (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of Other Operating Costs and Expense [Line Items]
Borrowed Funds	$ 18.4	$ 23.7	$ 25.6
Equity Funds	37.3	42	45
Total AFUDC	$ 55.7	$ 65.7	$ 70.6
Average AFUDC Rate	4.20%	5.00%	5.40%
The Connecticut Light and Power Company
Components of Other Operating Costs and Expense [Line Items]
Borrowed Funds	$ 2.9	$ 6.6	$ 7.1
Equity Funds	7.7	13.8	13.2
Total AFUDC	$ 10.6	$ 20.4	$ 20.3
Average AFUDC Rate	5.00%	5.90%	6.30%
NSTAR Electric Company
Components of Other Operating Costs and Expense [Line Items]
Borrowed Funds	$ 9	$ 9.1	$ 10.4
Equity Funds	20.4	21.5	19.8
Total AFUDC	$ 29.4	$ 30.6	$ 30.2
Average AFUDC Rate	4.90%	5.70%	5.70%
Public Service Company of New Hampshire
Components of Other Operating Costs and Expense [Line Items]
Borrowed Funds	$ 0.8	$ 2.1	$ 2.8
Equity Funds	1.6	4.2	3.4
Total AFUDC	$ 2.4	$ 6.3	$ 6.2
Average AFUDC Rate	2.50%	4.70%	4.60%

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Accounting Policies [Line Items]
Other Income, Net	$ 161,282	$ 108,590	$ 132,777
Unrealized gain associated with investment	14,200	14,200	42,200
Renewable Energy Fund
Summary of Accounting Policies [Line Items]
Other-than-temporary impairment		2,800
Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other Income, Net	84,400	44,400	31,300
AFUDC Equity
Summary of Accounting Policies [Line Items]
Other Income, Net	37,300	42,000	45,000
Equity in Earnings of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other Income, Net	14,200	14,200	42,200
Unrealized gain associated with investment	2,100	2,400	20,400
Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other Income, Net	(200)	1,100	800
Interest Income
Summary of Accounting Policies [Line Items]
Other Income, Net	25,600	4,800	12,800
Other
Summary of Accounting Policies [Line Items]
Other Income, Net	0	2,100	700
The Connecticut Light and Power Company
Summary of Accounting Policies [Line Items]
Other Income, Net	30,187	20,774	17,531
The Connecticut Light and Power Company | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other Income, Net	15,200	3,800	500
The Connecticut Light and Power Company | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other Income, Net	7,700	13,800	13,200
The Connecticut Light and Power Company | Equity in Earnings of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other Income, Net	0	0	100
The Connecticut Light and Power Company | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other Income, Net	1,300	1,100	2,300
The Connecticut Light and Power Company | Interest Income
Summary of Accounting Policies [Line Items]
Other Income, Net	5,900	2,000	1,500
The Connecticut Light and Power Company | Other
Summary of Accounting Policies [Line Items]
Other Income, Net	100	100	(100)
NSTAR Electric Company
Summary of Accounting Policies [Line Items]
Other Income, Net	74,844	52,017	44,577
NSTAR Electric Company | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other Income, Net	40,200	29,300	23,500
NSTAR Electric Company | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other Income, Net	20,400	21,500	19,800
NSTAR Electric Company | Equity in Earnings of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other Income, Net	400	400	700
NSTAR Electric Company | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other Income, Net	100	(800)	(400)
NSTAR Electric Company | Interest Income
Summary of Accounting Policies [Line Items]
Other Income, Net	13,400	900	700
NSTAR Electric Company | Other
Summary of Accounting Policies [Line Items]
Other Income, Net	300	700	300
Public Service Company of New Hampshire
Summary of Accounting Policies [Line Items]
Other Income, Net	14,565	13,786	19,222
Public Service Company of New Hampshire | Pension, SERP and PBOP Non-Service Income Components
Summary of Accounting Policies [Line Items]
Other Income, Net	10,300	7,000	4,900
Public Service Company of New Hampshire | AFUDC Equity
Summary of Accounting Policies [Line Items]
Other Income, Net	1,600	4,200	3,400
Public Service Company of New Hampshire | Equity in Earnings of Unconsolidated Affiliates
Summary of Accounting Policies [Line Items]
Other Income, Net	0	0	0
Public Service Company of New Hampshire | Investment Income/(Loss)
Summary of Accounting Policies [Line Items]
Other Income, Net	100	100	300
Public Service Company of New Hampshire | Interest Income
Summary of Accounting Policies [Line Items]
Other Income, Net	2,400	2,400	10,500
Public Service Company of New Hampshire | Other
Summary of Accounting Policies [Line Items]
Other Income, Net	$ 200	$ 100	$ 100

SUMMARY OF SIGNIFICANT ACCOU_11

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Other Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Accounting Policies [Line Items]
Excise and sales taxes	$ 181.9	$ 170.6	$ 163.1
The Connecticut Light and Power Company
Summary of Accounting Policies [Line Items]
Excise and sales taxes	$ 158.1	$ 149.9	$ 141.1

SUMMARY OF SIGNIFICANT ACCOU_12

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Paid During the Year for:
Interest, Net of Amounts Capitalized	$ 568.7	$ 518	$ 532.4
Income Taxes	121.6	48.9	56
Non-Cash Investing Activities:
Plant additionsincluded in accounts payable (as of)	467.9	367.2	379.4
The Connecticut Light and Power Company
Cash Paid During the Year for:
Interest, Net of Amounts Capitalized	161.5	149	144.6
Income Taxes	38.4	10.9	80.6
Non-Cash Investing Activities:
Plant additionsincluded in accounts payable (as of)	110.6	101.8	111.3
NSTAR Electric Company
Cash Paid During the Year for:
Interest, Net of Amounts Capitalized	141.6	129.4	121.9
Income Taxes	74.2	110.7	77.9
Non-Cash Investing Activities:
Plant additionsincluded in accounts payable (as of)	120	103.2	116.4
Public Service Company of New Hampshire
Cash Paid During the Year for:
Interest, Net of Amounts Capitalized	56.5	54.5	56.9
Income Taxes	51.1	34.2	3.4
Non-Cash Investing Activities:
Plant additionsincluded in accounts payable (as of)	$ 68.7	$ 33.3	$ 49.9

SUMMARY OF SIGNIFICANT ACCOU_13

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	$ 66,773	$ 106,599
Cash and Restricted Cash as reported on the Statements of Cash Flows	221,008	264,950	$ 117,063	$ 209,324
The Connecticut Light and Power Company
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	55,804	90,801
Cash and Restricted Cash as reported on the Statements of Cash Flows	74,788	99,809	4,971	91,613
NSTAR Electric Company
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	745	102
Cash and Restricted Cash as reported on the Statements of Cash Flows	18,179	17,410	6,312	14,659
Public Service Company of New Hampshire
Restricted Cash and Cash Equivalents Items [Line Items]
Cash as reported on the Balance Sheets	15	141
Cash and Restricted Cash as reported on the Statements of Cash Flows	35,126	39,555	$ 36,688	$ 52,723
Special Deposits
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	78,200	73,600
Special Deposits | The Connecticut Light and Power Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	18,700	8,700
Special Deposits | NSTAR Electric Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	17,400	17,200
Special Deposits | Public Service Company of New Hampshire
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	31,400	36,800
Marketable Securities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	31,300	41,200
Marketable Securities | The Connecticut Light and Power Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	300	300
Marketable Securities | NSTAR Electric Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	100	100
Marketable Securities | Public Service Company of New Hampshire
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	500	600
Other Long-Term Assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	44,700	43,600
Other Long-Term Assets | The Connecticut Light and Power Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	0	0
Other Long-Term Assets | NSTAR Electric Company
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 0	0
Other Long-Term Assets | Public Service Company of New Hampshire
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash		$ 2,100

REGULATORY ACCOUNTING - Compone

REGULATORY ACCOUNTING - Components of Regulatory Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 5,715,800	$ 6,569,900
Less:  Current Portion	1,129,093	1,076,556
Total Long-Term Regulatory Assets	4,586,709	5,493,330
Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	1,481,000	2,794,200
Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	790,700	747,100
Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	478,900	522,100
Storm Costs, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	1,102,700	765,600
Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	1,050,500	850,500
Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	249,200	296,300
Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	297,800	314,700
Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	115,000	118,400
Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	150,000	161,000
The Connecticut Light and Power Company
Regulatory Assets [Line Items]
Total Regulatory Assets	2,084,800	2,211,800
Less:  Current Portion	371,609	345,622
Total Long-Term Regulatory Assets	1,713,161	1,866,152
The Connecticut Light and Power Company | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	272,400	632,300
The Connecticut Light and Power Company | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	470,500	458,900
The Connecticut Light and Power Company | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
The Connecticut Light and Power Company | Storm Costs, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	695,600	515,100
The Connecticut Light and Power Company | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	333,600	246,600
The Connecticut Light and Power Company | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	249,200	293,100
The Connecticut Light and Power Company | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
The Connecticut Light and Power Company | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	33,600	32,100
The Connecticut Light and Power Company | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	29,900	33,700
NSTAR Electric Company
Regulatory Assets [Line Items]
Total Regulatory Assets	1,579,200	1,703,900
Less:  Current Portion	443,956	399,882
Total Long-Term Regulatory Assets	1,135,231	1,304,019
NSTAR Electric Company | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	395,500	690,000
NSTAR Electric Company | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	112,600	110,400
NSTAR Electric Company | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
NSTAR Electric Company | Storm Costs, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	341,300	186,400
NSTAR Electric Company | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	376,600	332,200
NSTAR Electric Company | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
NSTAR Electric Company | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	255,700	270,200
NSTAR Electric Company | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	59,800	58,600
NSTAR Electric Company | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	37,700	56,100
Public Service Company of New Hampshire
Regulatory Assets [Line Items]
Total Regulatory Assets	786,400	989,100
Less:  Current Portion	107,169	115,852
Total Long-Term Regulatory Assets	679,182	873,203
Public Service Company of New Hampshire | Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	118,900	267,600
Public Service Company of New Hampshire | Income Taxes, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	17,500	15,200
Public Service Company of New Hampshire | Securitized Stranded Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	478,900	522,100
Public Service Company of New Hampshire | Storm Costs, Net
Regulatory Assets [Line Items]
Total Regulatory Assets	65,800	64,100
Public Service Company of New Hampshire | Regulatory Tracker Mechanisms
Regulatory Assets [Line Items]
Total Regulatory Assets	85,400	95,300
Public Service Company of New Hampshire | Derivative Liabilities
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Public Service Company of New Hampshire | Goodwill-related
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Public Service Company of New Hampshire | Asset Retirement Obligations
Regulatory Assets [Line Items]
Total Regulatory Assets	4,100	3,900
Public Service Company of New Hampshire | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 15,800	$ 20,900

REGULATORY ACCOUNTING - Narrati

REGULATORY ACCOUNTING - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Oct. 01, 2021	Sep. 01, 2021	May 06, 2021	May 08, 2018
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	$ 252,500,000	$ 196,900,000
Regulatory assets	5,715,800,000	6,569,900,000
Deferred costs related to uncollectible expense	33,000,000	15,800,000
Regulatory Liabilities	602,432,000	389,430,000
FERC ROE Complaints
Regulatory Assets [Line Items]
Cumulative pre-tax reserves which include impact of refunds given to customers	39,100,000
COVID 19
Regulatory Assets [Line Items]
Deferred costs	39,800,000	24,000,000
Deferred Storm Restoration Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	1,010,000,000
Deferred Storm Restoration Costs | Tropical Storm Isaias
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	$ 251,000,000
Goodwill-related
Regulatory Assets [Line Items]
Recovery period	40 years
Remaining amortization	18 years
Regulatory assets	$ 297,800,000	314,700,000
Storm Costs, Net
Regulatory Assets [Line Items]
Regulatory assets	1,102,700,000	765,600,000
Public Service Company of New Hampshire
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	3,400,000	4,300,000
Regulatory assets	786,400,000	989,100,000
Equity return not recorded on the balance sheet	5,000,000	5,100,000
Regulatory Liabilities	120,176,000	58,756,000
Public Service Company of New Hampshire | FERC ROE Complaints
Regulatory Assets [Line Items]
Cumulative pre-tax reserves which include impact of refunds given to customers	3,100,000
Public Service Company of New Hampshire | Deferred Storm Restoration Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	61,000,000
Public Service Company of New Hampshire | Goodwill-related
Regulatory Assets [Line Items]
Regulatory assets	0	0
Public Service Company of New Hampshire | Storm Costs, Net
Regulatory Assets [Line Items]
Regulatory assets	65,800,000	64,100,000
The Connecticut Light and Power Company
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	114,900,000	84,100,000
Regulatory assets	2,084,800,000	2,211,800,000
Deferred costs related to uncollectible expense	19,000,000	4,700,000
Equity return not recorded on the balance sheet		200,000
Regulatory Liabilities	266,489,000	137,166,000
The Connecticut Light and Power Company | CL&P Rate Adjustment Mechanisms (RAM)
Regulatory Assets [Line Items]
Recovery of cumulative under-recoveries		193,000,000
The Connecticut Light and Power Company | FERC ROE Complaints
Regulatory Assets [Line Items]
Cumulative pre-tax reserves which include impact of refunds given to customers	21,400,000
The Connecticut Light and Power Company | Unfavorable Regulatory Action
Regulatory Assets [Line Items]
Regulatory Liabilities	75,000,000
Loss contingency, estimate of possible earnings impact, non-compliance with performance standards				$ 28,400,000	$ 28,400,000
Customer credits			$ 65,000,000
Customer assistance initiatives			$ 10,000,000
The Connecticut Light and Power Company | Deferred Pre-Staging And Storm Restoration Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	232,000,000	344,000,000
The Connecticut Light and Power Company | Deferred Storm Restoration Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	643,000,000
The Connecticut Light and Power Company | Deferred Storm Restoration Costs | Tropical Storm Isaias
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	234,000,000
The Connecticut Light and Power Company | Goodwill-related
Regulatory Assets [Line Items]
Regulatory assets	0	0
The Connecticut Light and Power Company | Storm Costs, Net
Regulatory Assets [Line Items]
Regulatory assets	695,600,000	515,100,000
NSTAR Electric Company
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	85,000,000	69,800,000
Regulatory assets	1,579,200,000	1,703,900,000
Deferred costs related to uncollectible expense	11,200,000	11,900,000
Regulatory Liabilities	228,248,000	164,761,000
NSTAR Electric Company | FERC ROE Complaints
Regulatory Assets [Line Items]
Cumulative pre-tax reserves which include impact of refunds given to customers	14,600,000
NSTAR Electric Company | Deferred Storm Restoration Costs
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	308,000,000
Amount of regulatory recovery not yet approved		7,200,000
Pre-tax benefit to earnings from settlement agreement	15,600,000	15,600,000
NSTAR Electric Company | Goodwill-related
Regulatory Assets [Line Items]
Regulatory assets	255,700,000	270,200,000
NSTAR Electric Company | Storm Costs, Net
Regulatory Assets [Line Items]
Regulatory assets	$ 341,300,000	$ 186,400,000
Rate Reduction Bonds | Public Service Company of New Hampshire
Regulatory Assets [Line Items]
Amount of securitized rate reduction bonds issued						$ 635,700,000

REGULATORY ACCOUNTING - Compo_2

REGULATORY ACCOUNTING - Components of Regulatory Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 4,468,700	$ 4,240,200
Less:  Current Portion	602,432	389,430
Total Long-Term Regulatory Liabilities	3,866,251	3,850,781
EDIT due to Tax Cuts and Jobs Act of 2017
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	2,685,200	2,778,600
Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	649,600	624,800
Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	133,500	83,600
Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	448,400	366,500
AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	81,000	76,800
CL&P Settlement Agreement and Storm Performance Penalty
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	81,300	0
Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	389,700	309,900
The Connecticut Light and Power Company
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,459,800	1,342,100
Less:  Current Portion	266,489	137,166
Total Long-Term Regulatory Liabilities	1,193,259	1,204,942
The Connecticut Light and Power Company | EDIT due to Tax Cuts and Jobs Act of 2017
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	996,100	1,010,700
The Connecticut Light and Power Company | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	100,100	98,400
The Connecticut Light and Power Company | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
The Connecticut Light and Power Company | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	182,000	148,900
The Connecticut Light and Power Company | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	43,200	44,600
The Connecticut Light and Power Company | CL&P Settlement Agreement and Storm Performance Penalty
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	81,300	0
The Connecticut Light and Power Company | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	57,100	39,500
NSTAR Electric Company
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	1,787,300	1,715,200
Less:  Current Portion	228,248	164,761
Total Long-Term Regulatory Liabilities	1,559,072	1,550,390
NSTAR Electric Company | EDIT due to Tax Cuts and Jobs Act of 2017
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	984,500	1,044,000
NSTAR Electric Company | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	381,000	363,600
NSTAR Electric Company | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	107,400	72,500
NSTAR Electric Company | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	185,100	139,700
NSTAR Electric Company | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	37,800	32,200
NSTAR Electric Company | CL&P Settlement Agreement and Storm Performance Penalty
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
NSTAR Electric Company | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	91,500	63,200
Public Service Company of New Hampshire
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	501,600	442,000
Less:  Current Portion	120,176	58,756
Total Long-Term Regulatory Liabilities	381,366	383,183
Public Service Company of New Hampshire | EDIT due to Tax Cuts and Jobs Act of 2017
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	359,200	371,500
Public Service Company of New Hampshire | Cost of Removal
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	17,200	12,900
Public Service Company of New Hampshire | Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Public Service Company of New Hampshire | Regulatory Tracker Mechanisms
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	107,000	47,800
Public Service Company of New Hampshire | AFUDC - Transmission
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Public Service Company of New Hampshire | CL&P Settlement Agreement and Storm Performance Penalty
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Public Service Company of New Hampshire | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 18,200	$ 9,800

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION - Investment in Utility Property, Plant and Equipment By Asset (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Distribution - Electric	$ 17,679,100	$ 16,703,200
Distribution - Natural Gas	6,694,800	6,111,200
Transmission - Electric	12,882,400	11,954,000
Distribution - Water	1,900,900	1,743,100
Solar	200,900	201,500
Utility	39,358,100	36,713,000
Other	1,469,500	1,269,000
Property, Plant and Equipment, Gross	40,827,600	37,982,000
Less:  Accumulated Depreciation
Utility	(8,885,200)	(8,476,300)
Other	(580,100)	(477,600)
Total Accumulated Depreciation	(9,465,300)	(8,953,900)
Property, Plant and Equipment, Net	31,362,300	29,028,100
Construction Work in Progress	2,015,400	1,854,400
Total Property, Plant and Equipment, Net	33,377,650	30,882,523
The Connecticut Light and Power Company
Property, Plant and Equipment [Line Items]
Distribution - Electric	7,117,600	6,820,700
Transmission - Electric	5,859,000	5,512,000
Solar	0	0
Property, Plant and Equipment, Gross	12,976,600	12,332,700
Less:  Accumulated Depreciation
Total Accumulated Depreciation	(2,572,100)	(2,475,400)
Property, Plant and Equipment, Net	10,404,500	9,857,300
Construction Work in Progress	399,000	377,300
Total Property, Plant and Equipment, Net	10,803,543	10,234,556
NSTAR Electric Company
Property, Plant and Equipment [Line Items]
Distribution - Electric	8,105,500	7,544,400
Transmission - Electric	5,090,500	4,701,300
Solar	200,900	201,500
Property, Plant and Equipment, Gross	13,396,900	12,447,200
Less:  Accumulated Depreciation
Total Accumulated Depreciation	(3,227,300)	(3,074,100)
Property, Plant and Equipment, Net	10,169,600	9,373,100
Construction Work in Progress	707,000	750,000
Total Property, Plant and Equipment, Net	10,876,614	10,123,062
Public Service Company of New Hampshire
Property, Plant and Equipment [Line Items]
Distribution - Electric	2,496,200	2,378,400
Transmission - Electric	1,934,600	1,742,400
Solar	0	0
Property, Plant and Equipment, Gross	4,430,800	4,120,800
Less:  Accumulated Depreciation
Total Accumulated Depreciation	(908,400)	(848,900)
Property, Plant and Equipment, Net	3,522,400	3,271,900
Construction Work in Progress	134,100	102,400
Total Property, Plant and Equipment, Net	$ 3,656,462	$ 3,374,270

PROPERTY, PLANT AND EQUIPMENT_4

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION -Narrative (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total Assets (as of)		$ 46,099,598	$ 48,492,144
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Hingham Water System
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 63,900
Goodwill	23,600
Proceeds from the sale of Hingham Water System	$ 110,500
Pre-tax gain (loss) on sale of property, plant and equipment		16,000
After-tax gain (loss) on the sale of property, plant and equipment		3,500
Eversource Gas Company of Massachusetts
Property, Plant and Equipment [Line Items]
Total Assets (as of)		$ 1,200,000

PROPERTY, PLANT AND EQUIPMENT_5

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION - Schedule of Aggregate Composite Depreciation Rates (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Composite depreciation rate for plant in service	3.10%	3.00%	3.00%
The Connecticut Light and Power Company
Property, Plant and Equipment [Line Items]
Composite depreciation rate for plant in service	2.80%	2.80%	2.80%
NSTAR Electric Company
Property, Plant and Equipment [Line Items]
Composite depreciation rate for plant in service	2.80%	2.80%	2.80%
Public Service Company of New Hampshire
Property, Plant and Equipment [Line Items]
Composite depreciation rate for plant in service	3.10%	2.80%	2.80%

PROPERTY, PLANT AND EQUIPMENT_6

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION - Schedule of Average Remaining Useful Lives of Depreciable Assets (Details)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Distribution - Electric	33 years 4 months 24 days
Distribution - Natural Gas	39 years 6 months
Transmission - Electric	40 years 2 months 12 days
Distribution - Water	38 years 6 months
Solar	24 years 2 months 12 days
Other	11 years 2 months 12 days
Computer Software, Hardware and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of property, plant and equipment	5 years
Computer Software, Hardware and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of property, plant and equipment	15 years
Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life of property, plant and equipment	40 years
The Connecticut Light and Power Company
Property, Plant and Equipment [Line Items]
Distribution - Electric	35 years 3 months 18 days
Transmission - Electric	36 years 6 months
NSTAR Electric Company
Property, Plant and Equipment [Line Items]
Distribution - Electric	33 years 1 month 6 days
Transmission - Electric	45 years 1 month 6 days
Solar	24 years 2 months 12 days
Public Service Company of New Hampshire
Property, Plant and Equipment [Line Items]
Distribution - Electric	29 years 8 months 12 days
Transmission - Electric	40 years 9 months 18 days

DERIVATIVE INSTRUMENTS - Schedu

DERIVATIVE INSTRUMENTS - Schedule of Gross Fair Value of Contracts (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Level 2 | Current Derivative Liabilities
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	$ 0	$ (3.3)
Netting	0	0.1
Net Amount Recorded as a Derivative	0	(3.2)
The Connecticut Light and Power Company | Level 3 | Current Derivative Assets
Current and Long-Term Derivative Assets
Commodity Supply and Price Risk Management	14.7	13.7
Netting	(1)	(0.4)
Net Amount Recorded as a Derivative	13.7	13.3
The Connecticut Light and Power Company | Level 3 | Long-Term Derivative Assets
Current and Long-Term Derivative Assets
Commodity Supply and Price Risk Management	46.9	58.7
Netting	(0.9)	(1.8)
Net Amount Recorded as a Derivative	46	56.9
The Connecticut Light and Power Company | Level 3 | Current Derivative Liabilities
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(73.5)	(68.8)
Netting	0	0
Net Amount Recorded as a Derivative	(73.5)	(68.8)
The Connecticut Light and Power Company | Level 3 | Long-Term Derivative Liabilities
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(235.4)	(294.5)
Netting	0	0
Net Amount Recorded as a Derivative	$ (235.4)	$ (294.5)

DERIVATIVE INSTRUMENTS - Deriva

DERIVATIVE INSTRUMENTS - Derivative Contracts at Fair Value (Details) MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)MMBTUMW	Dec. 31, 2019USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts by United Illuminated Company (as a percentage)	20.00%
Amount of power to be purchased under capacity-related contract (up to) (in MW) | MW		675
Amount of natural gas to be purchased under futures contracts (in MMBtu) | MMBTU		8.9
Loss deferred as regulatory costs | $	$ 7.1	$ 21.2	$ 20.7
The Connecticut Light and Power Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts (as a percentage)	80.00%
Minimum | Level 3
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts	5.00%
Minimum | Level 3 | The Connecticut Light and Power Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts	9.30%
Weighted Average | Level 3
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts	8.20%

DERIVATIVE INSTRUMENTS - Unobse

DERIVATIVE INSTRUMENTS - Unobservable Inputs Utilized (Details) - The Connecticut Light and Power Company - Level 3 - $ / KWmo	Dec. 31, 2021	Dec. 31, 2020
Capacity Prices | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	2.61	4.30
Capacity Prices | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input		5.30
Capacity Prices | Weighted Average
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	2.61	4.63
Forward Reserve | Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	0.50	0.54
Forward Reserve | Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	1.15	0.90
Forward Reserve | Weighted Average
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative measurement input	0.82	0.72

DERIVATIVE INSTRUMENTS - Variat

DERIVATIVE INSTRUMENTS - Variations Using Significant unobservable Inputs (Details) - Level 3 - The Connecticut Light and Power Company - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (293.1)	$ (329.2)
Net Realized/Unrealized Losses Included in Regulatory Assets	(8.5)	(17.9)
Settlements	52.4	54
Ending balance	$ (249.2)	$ (293.1)

MARKETABLE SECURITIES - Equity

MARKETABLE SECURITIES - Equity Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Equity securities	$ 40.2	$ 40.9
Unrealized gains recorded in other income	4.4	3.7
CYAPC and YAEC
Debt Securities, Available-for-sale [Line Items]
Equity securities	214	205.1
Marketable securities held in nuclear decommissioning trusts	$ 189.9	$ 192.5

MARKETABLE SECURITIES - Availab

MARKETABLE SECURITIES - Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Amortized Cost	$ 214.5	$ 213.1
Pre-Tax Unrealized Gains	5.1	11.2
Pre-Tax Unrealized Losses	(0.2)	(0.1)
Fair Value	$ 219.4	$ 224.2

MARKETABLE SECURITIES - Contrac

MARKETABLE SECURITIES - Contractual Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Amortized Cost
Less than one year	$ 32.2
One to five years	60.5
Six to ten years	35.7
Greater than ten years	86.1
Amortized Cost	214.5	$ 213.1
Fair Value
Less than one year	32.2
One to five years	61.4
Six to ten years	36.8
Greater than ten years	89
Total Debt Securities	$ 219.4	$ 224.2

MARKETABLE SECURITIES - Fair Va

MARKETABLE SECURITIES - Fair Value Measurement (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	$ 473.6	$ 470.2
Level 1
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	285.5	287.2
Level 1 | Mutual Funds and Equities
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	254.2	246
Level 1 | Money Market Funds
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	31.3	41.2
Level 2
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	188.1	183
Level 2 | U.S. Government Issued Debt Securities (Agency and Treasury)
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	81.3	72.9
Level 2 | Corporate Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	65.3	63.8
Level 2 | Asset-Backed Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	12.6	11.9
Level 2 | Municipal Bonds
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	12.3	24
Level 2 | Other Fixed Income Securities
Debt and Equity Securities, FV-NI [Line Items]
Total Marketable Securities	$ 16.6	$ 10.4

INVESTMENTS IN UNCONSOLIDATED_3

INVESTMENTS IN UNCONSOLIDATED AFFILIATES - Summary of Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affilitates	$ 1,436,293	$ 1,107,143
Offshore Wind Business - North East Offshore
Schedule of Equity Method Investments [Line Items]
Ownership interest	50.00%
Investments in unconsolidated affilitates	$ 1,213,600	887,100
Natural Gas Pipeline - Algonquin Gas Transmission, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest	15.00%
Investments in unconsolidated affilitates	$ 121,900	125,200
Renewable Energy Investment Fund
Schedule of Equity Method Investments [Line Items]
Ownership interest	90.00%
Investments in unconsolidated affilitates	$ 76,500	71,600
Other
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affilitates	$ 24,300	$ 23,200

INVESTMENTS IN UNCONSOLIDATED_4

INVESTMENTS IN UNCONSOLIDATED AFFILIATES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)company	Dec. 31, 2020USD ($)company	Dec. 31, 2019USD ($)	Feb. 08, 2019
Schedule of Equity Method Investments [Line Items]
Equity in earnings of unconsolidated affiliates, net of impairment	$ 14,200	$ 14,200	$ 42,200
Dividends received from equity method investees	$ 21,600	$ 21,800	48,900
Number of companies that transmit hydro electricity imported from The Hydro-Quebec System in Canada | company	2	2
Payments to acquire investments	$ 327,385	$ 239,673	$ 416,337
Offshore Wind Business - North East Offshore
Schedule of Equity Method Investments [Line Items]
Carrying amount of equity method investments in excess of the underlying equity in net assets	300,400	$ 264,100
Goodwill	$ 168,900
Ownership interest	50.00%
Revolution Wind And South Fork Wind
Schedule of Equity Method Investments [Line Items]
Ownership interest				50.00%
Hydro-Quebec System
Schedule of Equity Method Investments [Line Items]
Ownership interest	14.50%	14.50%
Payments to acquire investments	$ 9,000	$ 8,600
Renewable Energy Fund
Schedule of Equity Method Investments [Line Items]
Other-than-temporary impairment		$ 2,800

ASSET RETIREMENT OBLIGATIONS -

ASSET RETIREMENT OBLIGATIONS - Schedule of Reconciliation of Beginning and Ending Balance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of Beginning of Year	$ 499.7	$ 489.5
Liability Assumed Upon CMA Asset Acquisition	0	20.1
Liabilities Incurred During the Year	0	2.1
Liabilities Settled During the Year	(23.9)	(21.8)
Accretion	29.4	28.9
Revisions in Estimated Cash Flows	(5.1)	(19.1)
Balance as of End of Year	500.1	499.7
The Connecticut Light and Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of Beginning of Year	33.4	32
Liability Assumed Upon CMA Asset Acquisition	0	0
Liabilities Incurred During the Year	0	0
Liabilities Settled During the Year	(0.6)	(0.7)
Accretion	2.2	2.1
Revisions in Estimated Cash Flows	0	0
Balance as of End of Year	35	33.4
NSTAR Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of Beginning of Year	91.8	97.5
Liability Assumed Upon CMA Asset Acquisition	0	0
Liabilities Incurred During the Year	0	2.1
Liabilities Settled During the Year	0	(1)
Accretion	4	4.3
Revisions in Estimated Cash Flows	1.7	(11.1)
Balance as of End of Year	97.5	91.8
Public Service Company of New Hampshire
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of Beginning of Year	4.4	4.2
Liability Assumed Upon CMA Asset Acquisition	0	0
Liabilities Incurred During the Year	0	0
Liabilities Settled During the Year	0	0
Accretion	0.3	0.2
Revisions in Estimated Cash Flows	0	0
Balance as of End of Year	$ 4.7	$ 4.4

ASSET RETIREMENT OBLIGATIONS _2

ASSET RETIREMENT OBLIGATIONS - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Asset Retirement Obligation [Line Items]
Asset retirement obligations	$ 500.1	$ 499.7	$ 489.5
CYAPC and YAEC
Schedule of Asset Retirement Obligation [Line Items]
Asset retirement obligations	$ 325.9	$ 330.3

SHORT-TERM DEBT - Narrative (De

SHORT-TERM DEBT - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 03, 2021	Dec. 18, 2019
Commercial Paper | Eversource
Short-term Debt [Line Items]
Amount of commercial paper program	$ 2,000,000,000
Line of Credit
Short-term Debt [Line Items]
Amount outstanding during period	0	$ 0
Line of Credit | Eversource
Short-term Debt [Line Items]
Amount of commercial paper program	$ 2,000,000,000
Debt instrument term	5 years
The Connecticut Light and Power Company
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency			$ 600,000,000
The Connecticut Light and Power Company | Unsecured Debt
Short-term Debt [Line Items]
Period of maturity restricting provisions of debt	10 years
Total capitalization (as a percentage)	10.00%
Capacity available under preferred stock provisions	$ 963,600,000
The Connecticut Light and Power Company | Line of Credit
Short-term Debt [Line Items]
Amount of commercial paper program	450,000,000
Borrowings outstanding	0
NSTAR Electric Company
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency				$ 655,000,000
Notes payable to related parties	0	21,300,000
NSTAR Electric Company | Commercial Paper
Short-term Debt [Line Items]
Amount of commercial paper program	650,000,000
NSTAR Electric Company | Line of Credit
Short-term Debt [Line Items]
Amount of commercial paper program	$ 650,000,000
Debt instrument term	5 years
Public Service Company of New Hampshire
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency	$ 408,000,000
Notes payable to related parties	$ 110,600,000	$ 46,300,000
Public Service Company of New Hampshire | Short Term Debt Authorization Calculation
Short-term Debt [Line Items]
Interest rate	10.00%
Short-term debt borrowing calculation approved by regulatory agency	$ 60,000,000
Public Service Company of New Hampshire | Line of Credit
Short-term Debt [Line Items]
Amount of commercial paper program	$ 300,000,000

SHORT-TERM DEBT - Schedule of D

SHORT-TERM DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Borrowings Outstanding	$ 1,505,450	$ 1,249,325
Eversource Parent Commercial Paper Program
Line of Credit Facility [Line Items]
Borrowings Outstanding	1,342,950	1,054,325
Commercial Paper | Eversource Parent Commercial Paper Program
Line of Credit Facility [Line Items]
Borrowings Outstanding	1,343,000	1,054,300
Available Borrowing Capacity	$ 657,000	$ 945,700
Weighted-Average Interest Rate (as a percentage)	0.31%	0.25%
Commercial Paper | NSTAR Electric Company
Line of Credit Facility [Line Items]
Borrowings Outstanding	$ 162,500	$ 195,000
Available Borrowing Capacity	$ 487,500	$ 455,000
Weighted-Average Interest Rate (as a percentage)	0.14%	0.16%

LONG-TERM DEBT - Schedule of Lo

LONG-TERM DEBT - Schedule of Long-Term Debt Outstanding (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Oct. 31, 2021	Aug. 31, 2021	Jun. 30, 2021	May 31, 2021	Mar. 31, 2021	Dec. 31, 2020	Aug. 31, 2020
Debt Instrument [Line Items]
Long-Term Debt	$ 17,023,577						$ 15,125,876
Less Amounts due in One Year	(1,193,097)						(1,053,186)
Senior Notes
Debt Instrument [Line Items]
Unamortized Premiums and Discounts, Net	43,400						46,500
Unamortized Debt Issuance Costs	(36,300)						(32,000)
Long-Term Debt	17,023,600						15,125,900
Pre-1983 Spent Nuclear Fuel Obligation (CYAPC)
Debt Instrument [Line Items]
Long-Term Debt	11,700						11,700
Fair Value Adjustment
Debt Instrument [Line Items]
Long-Term Debt	43,800						74,700
Fair Value Adjustment - Current Portion
Debt Instrument [Line Items]
Long-Term Debt	(17,700)						(31,000)
Loans Payable
Debt Instrument [Line Items]
Less Amounts due in One Year	(775,400)						(490,200)
Total Other Long-Term Debt
Debt Instrument [Line Items]
Long-Term Debt	8,059,000						7,000,800
Eversource
Debt Instrument [Line Items]
Long-Term Debt	5,395,840						5,128,322
Less Amounts due in One Year	(767,681)						(473,933)
Eversource | Unsecured Debt | Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050
Debt Instrument [Line Items]
Long-Term Debt	$ 6,100,000						5,550,000
Eversource | Unsecured Debt | Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050 | Minimum
Debt Instrument [Line Items]
Interest rate	0.30%
Eversource | Unsecured Debt | Eversource Parent - Senior Notes 0.300% - 4.250% due 2022 - 2050 | Maximum
Debt Instrument [Line Items]
Interest rate	4.25%
The Connecticut Light and Power Company
Debt Instrument [Line Items]
Long-Term Debt	$ 4,215,379						3,914,835
The Connecticut Light and Power Company | 4.375% Fixed Rate Tax Exempt due 2028
Debt Instrument [Line Items]
Long-Term Debt	0						120,500
The Connecticut Light and Power Company | First Mortgage Bonds
Debt Instrument [Line Items]
Long-Term Debt	4,219,800						3,794,800
Unamortized Premiums and Discounts, Net	23,100						25,900
Unamortized Debt Issuance Costs	(27,500)						(26,400)
Long-Term Debt	$ 4,215,400						3,914,800
The Connecticut Light and Power Company | First Mortgage Bonds | 7.875% 1994 Series D due 2024
Debt Instrument [Line Items]
Interest rate	7.875%
Long-Term Debt	$ 139,800						139,800
The Connecticut Light and Power Company | First Mortgage Bonds | 5.750% 2004 Series B due 2034
Debt Instrument [Line Items]
Interest rate	5.75%
Long-Term Debt	$ 130,000						130,000
The Connecticut Light and Power Company | First Mortgage Bonds | 5.625% 2005 Series B due 2035
Debt Instrument [Line Items]
Interest rate	5.625%
Long-Term Debt	$ 100,000						100,000
The Connecticut Light and Power Company | First Mortgage Bonds | 6.350% 2006 Series A due 2036
Debt Instrument [Line Items]
Interest rate	6.35%
Long-Term Debt	$ 250,000						250,000
The Connecticut Light and Power Company | First Mortgage Bonds | 5.750% 2007 Series B due 2037
Debt Instrument [Line Items]
Interest rate	5.75%
Long-Term Debt	$ 150,000						150,000
The Connecticut Light and Power Company | First Mortgage Bonds | 6.375% 2007 Series D due 2037
Debt Instrument [Line Items]
Interest rate	6.375%
Long-Term Debt	$ 100,000						100,000
The Connecticut Light and Power Company | First Mortgage Bonds | 2.500% 2013 Series A due 2023
Debt Instrument [Line Items]
Interest rate	2.50%
Long-Term Debt	$ 400,000						400,000
The Connecticut Light and Power Company | First Mortgage Bonds | 4.300% 2014 Series A due 2044
Debt Instrument [Line Items]
Interest rate	4.30%
Long-Term Debt	$ 475,000						475,000
The Connecticut Light and Power Company | First Mortgage Bonds | 4.150% 2015 Series A due 2045
Debt Instrument [Line Items]
Interest rate	4.15%
Long-Term Debt	$ 350,000						350,000
The Connecticut Light and Power Company | First Mortgage Bonds | 3.200% 2017 Series A due 2027
Debt Instrument [Line Items]
Interest rate	3.20%
Long-Term Debt	$ 500,000						500,000
The Connecticut Light and Power Company | First Mortgage Bonds | 4.000% 2018 Series A due 2048
Debt Instrument [Line Items]
Interest rate	4.00%
Long-Term Debt	$ 800,000						800,000
The Connecticut Light and Power Company | First Mortgage Bonds | 0.750% 2020 Series A due 2025
Debt Instrument [Line Items]
Interest rate	0.75%
Long-Term Debt	$ 400,000						400,000
The Connecticut Light and Power Company | First Mortgage Bonds | 2.050% 2021 Series A due 2031
Debt Instrument [Line Items]
Interest rate	2.05%
Long-Term Debt	$ 425,000						0
NSTAR Electric Company
Debt Instrument [Line Items]
Long-Term Debt	3,585,399						3,393,221
Less Amounts due in One Year	(400,000)						(250,000)
NSTAR Electric Company | Unsecured Debt
Debt Instrument [Line Items]
Long-Term Debt	3,800,000						3,200,000
Less Amounts due in One Year	(400,000)						(250,000)
Unamortized Premiums and Discounts, Net	(11,200)						(6,800)
Unamortized Debt Issuance Costs	(23,400)						(20,000)
Long-Term Debt	$ 3,585,400						3,393,200
NSTAR Electric Company | Unsecured Debt | 5.750% due 2036
Debt Instrument [Line Items]
Interest rate	5.75%
Long-Term Debt	$ 200,000						200,000
NSTAR Electric Company | Unsecured Debt | 5.500% due 2040
Debt Instrument [Line Items]
Interest rate	5.50%
Long-Term Debt	$ 300,000						300,000
NSTAR Electric Company | Unsecured Debt | 2.375% due 2022
Debt Instrument [Line Items]
Interest rate	2.375%
Long-Term Debt	$ 400,000						400,000
NSTAR Electric Company | Unsecured Debt | 4.400% due 2044
Debt Instrument [Line Items]
Interest rate	4.40%
Long-Term Debt	$ 300,000						300,000
NSTAR Electric Company | Unsecured Debt | 3.250% due 2025
Debt Instrument [Line Items]
Interest rate	3.25%
Long-Term Debt	$ 250,000						250,000
NSTAR Electric Company | Unsecured Debt | 2.700% due 2026
Debt Instrument [Line Items]
Interest rate	2.70%
Long-Term Debt	$ 250,000						250,000
NSTAR Electric Company | Unsecured Debt | 3.200% due 2027
Debt Instrument [Line Items]
Interest rate	3.20%
Long-Term Debt	$ 700,000						700,000
NSTAR Electric Company | Unsecured Debt | 3.250% due 2029
Debt Instrument [Line Items]
Interest rate	3.25%
Long-Term Debt	$ 400,000						400,000
NSTAR Electric Company | Unsecured Debt | 3.950% due 2030
Debt Instrument [Line Items]
Interest rate	3.95%
Long-Term Debt	$ 400,000						400,000
NSTAR Electric Company | Unsecured Debt | 3.100% due 2051
Debt Instrument [Line Items]
Interest rate					3.10%
Long-Term Debt	300,000						0
NSTAR Electric Company | Unsecured Debt | 1.950% due 2031
Debt Instrument [Line Items]
Interest rate			1.95%
Long-Term Debt	300,000						0
NSTAR Electric Company | Senior Notes
Debt Instrument [Line Items]
Long-Term Debt	$ 220,000						470,000
NSTAR Electric Company | Senior Notes | 5.900% Senior Notes Series B due 2034
Debt Instrument [Line Items]
Interest rate	5.90%
Long-Term Debt	$ 50,000						50,000
NSTAR Electric Company | Senior Notes | 6.700% Senior Notes Series D due 2037
Debt Instrument [Line Items]
Interest rate	6.70%
Long-Term Debt	$ 40,000						40,000
NSTAR Electric Company | Senior Notes | 3.500% Senior Notes Series F due 2021
Debt Instrument [Line Items]
Interest rate				3.50%
Long-Term Debt	$ 0						250,000
NSTAR Electric Company | Senior Notes | 3.880% Senior Notes Series G due 2023
Debt Instrument [Line Items]
Interest rate	3.88%
Long-Term Debt	$ 80,000						80,000
NSTAR Electric Company | Senior Notes | 2.750% Senior Notes Series H due 2026
Debt Instrument [Line Items]
Interest rate	2.75%
Long-Term Debt	$ 50,000						50,000
Public Service Company of New Hampshire
Debt Instrument [Line Items]
Long-Term Debt	1,163,833						817,070
Less Amounts due in One Year	0						(282,000)
Public Service Company of New Hampshire | First Mortgage Bonds
Debt Instrument [Line Items]
Long-Term Debt	1,175,000						1,107,000
Less Amounts due in One Year	0						(282,000)
Unamortized Premiums and Discounts, Net	(2,600)						(1,500)
Unamortized Debt Issuance Costs	(8,600)						(6,400)
Long-Term Debt	$ 1,163,800						817,100
Public Service Company of New Hampshire | First Mortgage Bonds | 5.600% Series M due 2035
Debt Instrument [Line Items]
Interest rate	5.60%
Long-Term Debt	$ 50,000						50,000
Public Service Company of New Hampshire | First Mortgage Bonds | 4.050% Series Q due 2021
Debt Instrument [Line Items]
Interest rate						4.05%
Long-Term Debt	0						122,000
Public Service Company of New Hampshire | First Mortgage Bonds | 3.200% Series R due 2021
Debt Instrument [Line Items]
Interest rate				3.20%
Long-Term Debt	$ 0						160,000
Public Service Company of New Hampshire | First Mortgage Bonds | 3.500% Series S due 2023
Debt Instrument [Line Items]
Interest rate	3.50%
Long-Term Debt	$ 325,000						325,000
Public Service Company of New Hampshire | First Mortgage Bonds | 3.600% Series T due 2049
Debt Instrument [Line Items]
Interest rate	3.60%
Long-Term Debt	$ 300,000						300,000
Public Service Company of New Hampshire | First Mortgage Bonds | 2.400% Series U due 2050
Debt Instrument [Line Items]
Interest rate								2.40%
Long-Term Debt	150,000						150,000
Public Service Company of New Hampshire | First Mortgage Bonds | 2.200% Series V due 2031
Debt Instrument [Line Items]
Interest rate				2.20%
Long-Term Debt	350,000						0
Yankee Gas | First Mortgage Bonds | Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051
Debt Instrument [Line Items]
Long-Term Debt	$ 765,000						640,000
Yankee Gas | First Mortgage Bonds | Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 | Minimum
Debt Instrument [Line Items]
Interest rate	1.38%
Yankee Gas | First Mortgage Bonds | Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 | Maximum
Debt Instrument [Line Items]
Interest rate	8.48%
NSTAR Gas | First Mortgage Bonds | NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051
Debt Instrument [Line Items]
Long-Term Debt	$ 580,000						500,000
NSTAR Gas | First Mortgage Bonds | NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 | Minimum
Debt Instrument [Line Items]
Interest rate		2.25%
NSTAR Gas | First Mortgage Bonds | NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 | Maximum
Debt Instrument [Line Items]
Interest rate	7.11%
EGMA | First Mortgage Bonds | EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051
Debt Instrument [Line Items]
Long-Term Debt	$ 550,000						0
EGMA | First Mortgage Bonds | EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051 | Minimum
Debt Instrument [Line Items]
Interest rate	2.11%
EGMA | First Mortgage Bonds | EGMA - First Mortgage Bonds: 2.110% - 2.920% due 2031 - 2051 | Maximum
Debt Instrument [Line Items]
Interest rate	2.92%
Aquarion | Unsecured Debt | Aquarion - Senior Notes 4.000% due 2024
Debt Instrument [Line Items]
Long-Term Debt	$ 360,000						360,000
Aquarion | Unsecured Debt | Aquarion - Senior Notes 4.000% due 2024 | Maximum
Debt Instrument [Line Items]
Interest rate	4.00%
Aquarion | Unsecured Debt | Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051
Debt Instrument [Line Items]
Long-Term Debt	$ 394,900						335,200
Aquarion | Unsecured Debt | Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051 | Minimum
Debt Instrument [Line Items]
Interest rate	0.00%
Aquarion | Unsecured Debt | Aquarion - Unsecured Notes 0% - 6.430% due 2023 - 2051 | Maximum
Debt Instrument [Line Items]
Interest rate	6.43%
Aquarion | Secured Debt | Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044
Debt Instrument [Line Items]
Long-Term Debt	$ 39,600						$ 35,900
Aquarion | Secured Debt | Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044 | Minimum
Debt Instrument [Line Items]
Interest rate	1.296%
Aquarion | Secured Debt | Aquarion - Secured Debt 1.296% - 9.290% due 2022 - 2044 | Maximum
Debt Instrument [Line Items]
Interest rate	9.29%

LONG-TERM DEBT - Schedule of Is

LONG-TERM DEBT - Schedule of Issuances and Repayments (Details) - USD ($) $ in Thousands

Aug. 13, 2021

Oct. 31, 2021

Sep. 30, 2021

Aug. 31, 2021

Jun. 30, 2021

Apr. 30, 2021

Mar. 31, 2021

Feb. 28, 2021

May 31, 2020

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

May 31, 2021

Debt Instrument [Line Items]

Repayments of debt

$ (1,142,500)

$ (327,236)

$ (801,078)

Senior Notes

Debt Instrument [Line Items]

Long-term debt

17,023,600

15,125,900

The Connecticut Light and Power Company

Debt Instrument [Line Items]

Repayments of debt

$ (120,500)

0

(250,000)

The Connecticut Light and Power Company | Senior Notes | 4.38% Series A PCRB

Debt Instrument [Line Items]

Interest rate

4.38%

4.375%

Repayments of debt

$ (120,500)

The Connecticut Light and Power Company | PSNH 4.050% Series Q First Mortgage Bond

Debt Instrument [Line Items]

Long-term debt

$ 4,215,400

3,914,800

The Connecticut Light and Power Company | PSNH 4.050% Series Q First Mortgage Bond | 2.050% 2021 Series A due 2031

Debt Instrument [Line Items]

Interest rate

2.05%

Issuance

$ 425,000

NSTAR Electric Company

Debt Instrument [Line Items]

Repayments of debt

$ (250,000)

(95,000)

0

NSTAR Electric Company | Senior Notes | 3.500% Senior Notes Series F due 2021

Debt Instrument [Line Items]

Interest rate

3.50%

Repayments of debt

$ (250,000)

NSTAR Electric Company | Unsecured Debt [Member]

Debt Instrument [Line Items]

Long-term debt

3,585,400

3,393,200

NSTAR Electric Company | Unsecured Debt [Member] | 3.100% due 2051

Debt Instrument [Line Items]

Interest rate

3.10%

Issuance

$ 300,000

NSTAR Electric Company | Unsecured Debt [Member] | 1.950% due 2031

Debt Instrument [Line Items]

Interest rate

1.95%

Issuance

$ 300,000

Public Service Company of New Hampshire

Debt Instrument [Line Items]

Repayments of debt

(282,000)

0

(150,000)

Public Service Company of New Hampshire | PSNH 4.050% Series Q First Mortgage Bond

Debt Instrument [Line Items]

Long-term debt

$ 1,163,800

817,100

Public Service Company of New Hampshire | PSNH 4.050% Series Q First Mortgage Bond | 4.050% Series Q due 2021

Debt Instrument [Line Items]

Interest rate

4.05%

Repayments of debt

$ (122,000)

Public Service Company of New Hampshire | PSNH 4.050% Series Q First Mortgage Bond | 3.200% Series R due 2021

Debt Instrument [Line Items]

Interest rate

3.20%

Repayments of debt

$ (160,000)

Public Service Company of New Hampshire | PSNH 4.050% Series Q First Mortgage Bond | 2.200% Series V due 2031

Debt Instrument [Line Items]

Interest rate

2.20%

Issuance

$ 350,000

Aquarion | Senior Notes | Aquarion Water Company of Connecticut 3.31% Senior Notes

Debt Instrument [Line Items]

Interest rate

3.31%

Issuance

$ 100,000

Aquarion | Senior Notes | Aquarion Water Company of Connecticut 5.50% Notes

Debt Instrument [Line Items]

Interest rate

5.50%

Repayments of debt

$ (40,000)

Yankee Gas | Senior Notes | Yankee Gas 2.88% Series T First Mortgage Bonds

Debt Instrument [Line Items]

Interest rate

2.88%

Issuance

$ 35,000

Yankee Gas | PSNH 4.050% Series Q First Mortgage Bond | Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051

Debt Instrument [Line Items]

Issuance

$ 90,000

Yankee Gas | PSNH 4.050% Series Q First Mortgage Bond | Yankee Gas - First Mortgage Bonds: 1.380% - 8.480% due 2022 - 2051 | Minimum

Debt Instrument [Line Items]

Interest rate

1.38%

EGMA | Senior Notes

Debt Instrument [Line Items]

Refinanced amount

$ 309,400

EGMA | Senior Notes | EGMA 2.11% Series A First Mortgage Bonds

Debt Instrument [Line Items]

Issuance

310,000

EGMA | Senior Notes | EGMA 2.92% Series B First Mortgage Bonds

Debt Instrument [Line Items]

Issuance

$ 240,000

NSTAR Gas | Senior Notes | NSTAR Gas 3.03% Series U First Mortgage Bonds

Debt Instrument [Line Items]

Interest rate

3.03%

Issuance

$ 40,000

NSTAR Gas | PSNH 4.050% Series Q First Mortgage Bond | NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051

Debt Instrument [Line Items]

Issuance

$ 40,000

NSTAR Gas | PSNH 4.050% Series Q First Mortgage Bond | NSTAR Gas - First Mortgage Bonds: 2.250% - 7.110% due 2025 - 2051 | Minimum

Debt Instrument [Line Items]

Interest rate

2.25%

Eversource

Debt Instrument [Line Items]

Repayments of debt

$ (450,000)

$ 0

$ (350,000)

Eversource | Senior Notes | Eversource Parent 2.50% Series I Senior Notes

Debt Instrument [Line Items]

Interest rate

2.50%

Repayments of debt

$ (450,000)

Eversource | Senior Notes | Eversource Parent 2.55% Series S Senior Notes

Debt Instrument [Line Items]

Interest rate

2.55%

Issuance

$ 350,000

Eversource | Senior Notes | Eversource Parent 1.40% Series U Senior Notes

Debt Instrument [Line Items]

Interest rate

1.40%

Issuance

$ 300,000

Eversource | Senior Notes | Eversource Parent Variable Rate Series T Senior Notes

Debt Instrument [Line Items]

Interest rate

0.30%

Issuance

$ 350,000

$ 350,000

Eversource | Senior Notes | Eversource Parent Variable Rate Series T Senior Notes | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate

Debt Instrument [Line Items]

Basis spread on compounded SOFR

0.25%

LONG-TERM DEBT - Narrative (Det

LONG-TERM DEBT - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 10, 2021	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt	$ 17,023,577			$ 15,125,876
Interest included in payment to settle spent nuclear fuel obligation				8,700
Pre-1983 Spent Nuclear Fuel Obligation (CYAPC)
Debt Instrument [Line Items]
Long-term debt	11,700			11,700
NSTAR Electric Company
Debt Instrument [Line Items]
Amount of long-term debt requested for issuance			$ 1,600,000
Long-term debt	$ 3,585,399			$ 3,393,221
Massachusetts Department of Public Utilities
Debt Instrument [Line Items]
Amount of long-term debt requested for issuance		$ 725,000

LONG-TERM DEBT - Schedule of _2

LONG-TERM DEBT - Schedule of Long-term Debt Maturities (Details) $ in Millions	Dec. 31, 2021USD ($)
Debt Instrument [Line Items]
2022	$ 1,175.4
2023	2,008.4
2024	1,050.1
2025	1,400.2
2026	940.2
Thereafter	11,630
Total	18,204.3
The Connecticut Light and Power Company
Debt Instrument [Line Items]
2022	0
2023	400
2024	139.8
2025	400
2026	0
Thereafter	3,280
Total	4,219.8
NSTAR Electric Company
Debt Instrument [Line Items]
2022	400
2023	80
2024	0
2025	250
2026	300
Thereafter	2,990
Total	4,020
Public Service Company of New Hampshire
Debt Instrument [Line Items]
2022	0
2023	325
2024	0
2025	0
2026	0
Thereafter	850
Total	$ 1,175

RATE REDUCTION BONDS AND VARI_3

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Narrative (Details) - Public Service Company of New Hampshire - Rate Reduction Bonds	May 08, 2018USD ($)
Debt Instrument [Line Items]
Amount of securitized rate reduction bonds issued	$ 635,700,000
Weighted average interest rate	3.66%

RATE REDUCTION BONDS AND VARI_4

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	$ 5,715,800	$ 6,569,900
Regulatory Liabilities	3,866,251	3,850,781
Accrued Interest (included in Other Current Liabilities)	830,620	809,214
Rate Reduction Bonds - Current Portion	43,210	43,210
Rate Reduction Bonds - Long-Term Portion	453,702	496,912
Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	478,900	522,100
Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	150,000	161,000
Special Deposits
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	78,200	73,600
Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	44,700	43,600
Public Service Company of New Hampshire
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	786,400	989,100
Regulatory Liabilities	381,366	383,183
Accrued Interest (included in Other Current Liabilities)	63,005	58,487
Rate Reduction Bonds - Current Portion	43,210	43,210
Rate Reduction Bonds - Long-Term Portion	453,702	496,912
Public Service Company of New Hampshire | Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	478,900	522,100
Public Service Company of New Hampshire | Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	15,800	20,900
Public Service Company of New Hampshire | Special Deposits
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	31,400	36,800
Public Service Company of New Hampshire | Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash		2,100
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire
Condensed Balance Sheet Statements, Captions [Line Items]
Rate Reduction Bonds - Current Portion	43,200	43,200
Rate Reduction Bonds - Long-Term Portion	453,700	496,900
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire | Securitized Stranded Costs
Condensed Balance Sheet Statements, Captions [Line Items]
Securitized Stranded Cost (included in Regulatory Assets)	478,900	522,100
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire | Other Regulatory Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Regulatory Liabilities	5,400	9,100
Accrued Interest (included in Other Current Liabilities)	7,500	8,000
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire | Special Deposits
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	31,100	36,800
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire | Other Long-Term Assets
Condensed Balance Sheet Statements, Captions [Line Items]
Restricted Cash	$ 3,200	$ 2,100

RATE REDUCTION BONDS AND VARI_5

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Income Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Interest Expense on RRB Principal (included in Interest Expense)	$ 582,334	$ 538,452	$ 533,197
Public Service Company of New Hampshire
Condensed Income Statements, Captions [Line Items]
Amortization of Regulatory Assets, Net	86,832	52,804	57,732
Interest Expense on RRB Principal (included in Interest Expense)	56,998	58,127	60,666
Variable Interest Entity, Primary Beneficiary | Public Service Company of New Hampshire | Rate Reduction Bonds
Condensed Income Statements, Captions [Line Items]
Amortization of Regulatory Assets, Net	43,200	43,200	43,000
Interest Expense on RRB Principal (included in Interest Expense)	$ 18,400	$ 19,700	$ 21,100

RATE REDUCTION BONDS AND VARI_6

RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES- Rate Reduction Bonds, Principal and Interest Payments (Details) $ in Millions	Dec. 31, 2021USD ($)
Debt Disclosure [Abstract]
2022	$ 43.2
2023	43.2
2024	43.2
2025	43.2
2026	43.2
Thereafter	280.9
Total	$ 496.9

EMPLOYEE BENEFITS - Schedule of

EMPLOYEE BENEFITS - Schedule of Pension Benefit Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	$ (7,045.3)	$ (6,321.7)
Service Cost	(85.8)	(76.2)	$ (67.7)
Interest Cost	(130)	(177.8)	(219)
Actuarial Gain/(Loss)	177.1	(658.2)
Benefits Paid	309.5	279.3
Benefits Paid - Lump Sum	34.7	23.4
Benefits Paid - SERP	10.1	7.3
Employee Transfers	0	0
Increase due to acquisition of CMA	0	(121.4)
Benefit Obligation as of End of Year	(6,729.7)	(7,045.3)	(6,321.7)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	5,409.2	4,968.6
Employer Contributions	180	109.6
Actual Return on Plan Assets	1,250.5	512.3
Benefits Paid - Pension	(309.5)	(279.3)
Benefits Paid - Lump Sum	(34.7)	(23.4)
Employee Transfers	0	0
Increase due to acquisition of CMA	0	121.4
Fair Value of Plan Assets as of End of Year	6,495.5	5,409.2	4,968.6
Funded Status as of December 31st	(234.2)	(1,636.1)
Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(993.9)	(899)
Service Cost	(13.5)	(10.2)	(7.8)
Interest Cost	(17.4)	(24.6)	(32.7)
Actuarial Gain/(Loss)	81.4	(82.8)
Benefits Paid	51.7	50.2
Employee Transfers	0	0
Increase due to acquisition of CMA	7.4	(27.5)
Benefit Obligation as of End of Year	(884.3)	(993.9)	(899)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	1,004.1	935.9
Employer Contributions	2.3	1.9
Actual Return on Plan Assets	183.2	116.5
Benefits Paid - Pension	(51.3)	(50.2)
Employee Transfers	0	0
Fair Value of Plan Assets as of End of Year	1,138.3	1,004.1	935.9
Funded Status as of December 31st	254	10.2
The Connecticut Light and Power Company | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(1,477.3)	(1,331.3)
Service Cost	(23)	(21.8)	(18)
Interest Cost	(27.3)	(37.3)	(45.7)
Actuarial Gain/(Loss)	127.8	(152.3)
Benefits Paid	64.6	63.6
Benefits Paid - Lump Sum	0	0
Benefits Paid - SERP	0.3	0.3
Employee Transfers	4	1.5
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(1,330.9)	(1,477.3)	(1,331.3)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	1,043.1	986.2
Employer Contributions	98.9	23.2
Actual Return on Plan Assets	250.4	98.8
Benefits Paid - Pension	(64.6)	(63.6)
Benefits Paid - Lump Sum	0	0
Employee Transfers	(4)	(1.5)
Increase due to acquisition of CMA	0	0
Fair Value of Plan Assets as of End of Year	1,323.8	1,043.1	986.2
Funded Status as of December 31st	(7.1)	(434.2)
The Connecticut Light and Power Company | Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(178.6)	(172.7)
Service Cost	(2.3)	(1.7)	(1.4)
Interest Cost	(3.2)	(4.4)	(6.3)
Actuarial Gain/(Loss)	5.8	(8.6)
Benefits Paid	10.9	10.1
Employee Transfers	1.9	(1.3)
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(165.5)	(178.6)	(172.7)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	134.1	126.3
Employer Contributions	0	0
Actual Return on Plan Assets	24.1	15.7
Benefits Paid - Pension	(10.9)	(10.1)
Employee Transfers	(1.6)	2.2
Fair Value of Plan Assets as of End of Year	145.7	134.1	126.3
Funded Status as of December 31st	(19.8)	(44.5)
NSTAR Electric Company | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(1,517.9)	(1,397.3)
Service Cost	(15.8)	(15.4)	(14.6)
Interest Cost	(26.8)	(38.6)	(49)
Actuarial Gain/(Loss)	20.8	(139.5)
Benefits Paid	68.7	59.4
Benefits Paid - Lump Sum	15.6	13.1
Benefits Paid - SERP	0.2	0.2
Employee Transfers	6.8	0.2
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(1,448.4)	(1,517.9)	(1,397.3)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	1,345.1	1,288.8
Employer Contributions	30	0.7
Actual Return on Plan Assets	312	128.3
Benefits Paid - Pension	(68.7)	(59.4)
Benefits Paid - Lump Sum	(15.6)	(13.1)
Employee Transfers	(6.8)	(0.2)
Increase due to acquisition of CMA	0	0
Fair Value of Plan Assets as of End of Year	1,596	1,345.1	1,288.8
Funded Status as of December 31st	147.6	(172.8)
NSTAR Electric Company | Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(260.5)	(258.3)
Service Cost	(2.4)	(2.1)	(1.7)
Interest Cost	(4.4)	(6.6)	(9.5)
Actuarial Gain/(Loss)	11.5	(7.4)
Benefits Paid	16.3	14.9
Employee Transfers	1.1	(1)
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(238.4)	(260.5)	(258.3)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	464.6	424.4
Employer Contributions	0	0
Actual Return on Plan Assets	84.2	53.3
Benefits Paid - Pension	(16.3)	(14.9)
Employee Transfers	(2.5)	1.8
Fair Value of Plan Assets as of End of Year	530	464.6	424.4
Funded Status as of December 31st	291.6	204.1
Public Service Company of New Hampshire | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(748.7)	(692.6)
Service Cost	(8.9)	(8.2)	(7.1)
Interest Cost	(14.5)	(19.4)	(24)
Actuarial Gain/(Loss)	14.7	(62.1)
Benefits Paid	34.7	33.5
Benefits Paid - Lump Sum	0	0
Benefits Paid - SERP	0.4	0.4
Employee Transfers	1.3	(0.3)
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(721)	(748.7)	(692.6)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	593.7	551.6
Employer Contributions	0	19.5
Actual Return on Plan Assets	136.9	55.8
Benefits Paid - Pension	(34.7)	(33.5)
Benefits Paid - Lump Sum	0	0
Employee Transfers	(1.3)	0.3
Increase due to acquisition of CMA	0	0
Fair Value of Plan Assets as of End of Year	694.6	593.7	551.6
Funded Status as of December 31st	(26.4)	(155)
Public Service Company of New Hampshire | Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation as of Beginning of Year	(109.5)	(93)
Service Cost	(1.2)	(0.9)	(0.7)
Interest Cost	(1.8)	(2.8)	(3.4)
Actuarial Gain/(Loss)	14.6	(19)
Benefits Paid	5.6	6.1
Employee Transfers	0	0.1
Increase due to acquisition of CMA	0	0
Benefit Obligation as of End of Year	(92.3)	(109.5)	(93)
Change in Pension Plan Assets:
Fair Value of Plan Assets as of Beginning of Year	79.4	76
Employer Contributions	0	0
Actual Return on Plan Assets	14.2	9.3
Benefits Paid - Pension	(5.6)	(6.1)
Employee Transfers	0	0.2
Fair Value of Plan Assets as of End of Year	88	79.4	$ 76
Funded Status as of December 31st	$ (4.3)	$ (30.1)

EMPLOYEE BENEFITS - Pension Pla

EMPLOYEE BENEFITS - Pension Plan Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Liability	$ 242,463	$ 1,653,788
Expected long-term rate of return	7.00%	7.00%
The Connecticut Light and Power Company
Defined Contribution Plan Disclosure [Line Items]
Liability	$ 26,820	$ 478,325
Public Service Company of New Hampshire
Defined Contribution Plan Disclosure [Line Items]
Liability	30,184	184,715
Pension Plan
Defined Contribution Plan Disclosure [Line Items]
Increase in liability due to amendment in pension plan	286,800	603,000
Funded status of plan	$ (234,200)	$ (1,636,100)
Expected long-term rate of return	8.25%	8.25%	8.25%
Pension Plan | The Connecticut Light and Power Company
Defined Contribution Plan Disclosure [Line Items]
Funded status of plan	$ (7,100)	$ (434,200)
Pension Plan | Public Service Company of New Hampshire
Defined Contribution Plan Disclosure [Line Items]
Funded status of plan	(26,400)	(155,000)
Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Increase in liability due to amendment in pension plan	29,800	68,300
Funded status of plan	$ 254,000	$ 10,200
Expected long-term rate of return	8.25%	8.25%	8.25%
Estimated future employer contributions in next fiscal year	$ 2,400
Other Postretirement Benefits Plan | The Connecticut Light and Power Company
Defined Contribution Plan Disclosure [Line Items]
Funded status of plan	(19,800)	$ (44,500)
Other Postretirement Benefits Plan | Public Service Company of New Hampshire
Defined Contribution Plan Disclosure [Line Items]
Funded status of plan	(4,300)	(30,100)
Other Current Liabilities
Defined Contribution Plan Disclosure [Line Items]
Funded status of plan	9,700	6,800
Other Long-Term Assets | Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Prepaid asset	272,000	34,700
Accrued Pension, SERP and PBOP | Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Liability	18,000	$ 24,500
Minimum | Pension Plan
Defined Contribution Plan Disclosure [Line Items]
Estimated future employer contributions in next fiscal year	100,000
Maximum | Pension Plan
Defined Contribution Plan Disclosure [Line Items]
Estimated future employer contributions in next fiscal year	$ 175,000
Pre-65 Plan | Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	6.50%
Ultimate rate	5.00%
Pre-65 Plan | Minimum | Other Postretirement Benefits Plan | Aquarion
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	3.50%	3.50%
Pre-65 Plan | Maximum | Other Postretirement Benefits Plan | Aquarion
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	6.20%	6.50%
Post-65 Plan | Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Ultimate rate	3.50%
Eversource Service Pension and PBOP Plans
Defined Contribution Plan Disclosure [Line Items]
Assumed rate of return	8.25%
Aquarion Plans
Defined Contribution Plan Disclosure [Line Items]
Assumed rate of return	7.00%

EMPLOYEE BENEFITS - Schedule _2

EMPLOYEE BENEFITS - Schedule of Funded Status (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 6,337.3	$ 6,669.4
The Connecticut Light and Power Company
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	1,241.1	1,356.4
NSTAR Electric Company
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	1,376.1	1,449.4
Public Service Company of New Hampshire
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 670.3	$ 707.2

EMPLOYEE BENEFITS - Schedule _3

EMPLOYEE BENEFITS - Schedule of Actuarial Assumptions (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	2.80%	2.40%
Compensation/Progression Rate	3.50%	3.50%
Pension Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	3.00%	2.70%
Compensation/Progression Rate	4.00%	4.00%
Other Postretirement Benefits Plan | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	2.91%	2.50%
Other Postretirement Benefits Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	2.92%	2.60%
Pre-65 Plan | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Health care trend rate	6.50%

EMPLOYEE BENEFITS - Schedule _4

EMPLOYEE BENEFITS - Schedule of Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 85.8	$ 76.2	$ 67.7
Interest Cost	130	177.8	219
Expected Return on Plan Assets	(437.5)	(400.3)	(367.1)
Actuarial Loss	243.9	202	143.2
Prior Service Cost/(Credit)	1.4	1.2	0.9
Total Net Periodic Benefit Plan Expense/(Income)	23.6	56.9	63.7
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	13.5	10.2	7.8
Interest Cost	17.4	24.6	32.7
Expected Return on Plan Assets	(79.1)	(73.6)	(66.8)
Actuarial Loss	8.9	8.4	8.3
Prior Service Cost/(Credit)	(21.2)	(21.2)	(23.5)
Total Net Periodic Benefit Plan Expense/(Income)	(60.5)	(51.6)	(41.5)
The Connecticut Light and Power Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	23	21.8	18
Interest Cost	27.3	37.3	45.7
Expected Return on Plan Assets	(86.8)	(79.2)	(73.2)
Actuarial Loss	45.5	39.2	26.9
Prior Service Cost/(Credit)	0	0	0
Total Net Periodic Benefit Plan Expense/(Income)	9	19.1	17.4
Intercompany Expense/(Income) Allocations	8	9.1	8.5
The Connecticut Light and Power Company | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	2.3	1.7	1.4
Interest Cost	3.2	4.4	6.3
Expected Return on Plan Assets	(10.3)	(9.9)	(9.2)
Actuarial Loss	1.8	1.1	1.3
Prior Service Cost/(Credit)	1.1	1.1	1.1
Total Net Periodic Benefit Plan Expense/(Income)	(1.9)	(1.6)	0.9
Intercompany Expense/(Income) Allocations	(1.6)	(1.1)	(0.9)
NSTAR Electric Company | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	15.8	15.4	14.6
Interest Cost	26.8	38.6	49
Expected Return on Plan Assets	(108.1)	(103)	(97.1)
Actuarial Loss	61.6	55.2	44.7
Prior Service Cost/(Credit)	0.3	0.3	0.3
Total Net Periodic Benefit Plan Expense/(Income)	(3.6)	6.5	11.5
Intercompany Expense/(Income) Allocations	8.8	8.9	8
NSTAR Electric Company | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	2.4	2.1	1.7
Interest Cost	4.4	6.6	9.5
Expected Return on Plan Assets	(36.9)	(34)	(30.2)
Actuarial Loss	2.4	2.5	3.3
Prior Service Cost/(Credit)	(17)	(17)	(16.9)
Total Net Periodic Benefit Plan Expense/(Income)	(44.7)	(39.8)	(32.6)
Intercompany Expense/(Income) Allocations	(1.9)	(1.4)	(1.2)
Public Service Company of New Hampshire | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	8.9	8.2	7.1
Interest Cost	14.5	19.4	24
Expected Return on Plan Assets	(47.5)	(44.7)	(40.7)
Actuarial Loss	20.7	15.6	10.6
Prior Service Cost/(Credit)	0	0	0
Total Net Periodic Benefit Plan Expense/(Income)	(3.4)	(1.5)	1
Intercompany Expense/(Income) Allocations	2.7	2.9	2.3
Public Service Company of New Hampshire | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	1.2	0.9	0.7
Interest Cost	1.8	2.8	3.4
Expected Return on Plan Assets	(6.1)	(5.7)	(5.4)
Actuarial Loss	0.7	0.8	0.3
Prior Service Cost/(Credit)	0.4	0.4	0.4
Total Net Periodic Benefit Plan Expense/(Income)	(2)	(0.8)	(0.6)
Intercompany Expense/(Income) Allocations	$ (0.6)	$ (0.5)	$ (0.4)

EMPLOYEE BENEFITS - Schedule _5

EMPLOYEE BENEFITS - Schedule of Assumptions used To Calculate Pension and SERP and PBOP (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Expected Long-Term Rate of Return	7.00%	7.00%
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Expected Long-Term Rate of Return	8.25%	8.25%	8.25%
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Expected Long-Term Rate of Return	8.25%	8.25%	8.25%
Minimum | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	1.50%	2.60%	2.70%
Compensation/Progression Rate	3.50%	3.50%	3.50%
Minimum | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	1.80%	2.70%	3.90%
Maximum | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	3.00%	3.50%	3.60%
Compensation/Progression Rate	4.00%	4.00%
Maximum | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	3.10%	3.60%	4.60%

EMPLOYEE BENEFITS - Summary of

EMPLOYEE BENEFITS - Summary of Changes in Plan Assets and Benefit Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension Plan
Net Regulatory Assets [Abstract]
Actuarial (Gains)/Losses Arising During the Year	$ (961.7)	$ 553.1
Actuarial Losses Reclassified as Net Periodic Benefit Expense	(231.2)	(194.3)
Prior Service Cost Arising During the Year	0	2
Prior Service (Cost)/Credit Reclassified as Net Periodic Benefit (Expense)/Income	(1.3)	(1)
Actuarial Loss	1,427.3	2,620.2
Prior Service Cost	5.3	6.6
OCI
Actuarial (Gains)/Losses Arising During the Year	(28.4)	24.3
Actuarial Losses Reclassified as Net Periodic Benefit Expense	(12.7)	(7.7)
Prior Service Cost Arising During the Year	0	0
Prior Service (Cost)/Credit Reclassified as Net Periodic Benefit (Expense)/Income	(0.1)	(0.2)
Actuarial Loss	66.3	107.4
Prior Service Cost	0.6	0.7
Other Postretirement Benefits Plan
Net Regulatory Assets [Abstract]
Actuarial (Gains)/Losses Arising During the Year	(181.5)	39.1
Actuarial Losses Reclassified as Net Periodic Benefit Expense	(8.5)	(8)
Prior Service Cost Arising During the Year	0	0
Prior Service (Cost)/Credit Reclassified as Net Periodic Benefit (Expense)/Income	21.1	21.3
Actuarial Loss	45	235
Prior Service Cost	(130.1)	(151.2)
OCI
Actuarial (Gains)/Losses Arising During the Year	(4)	1.3
Actuarial Losses Reclassified as Net Periodic Benefit Expense	(0.4)	(0.4)
Prior Service Cost Arising During the Year	0	0
Prior Service (Cost)/Credit Reclassified as Net Periodic Benefit (Expense)/Income	0.1	(0.1)
Actuarial Loss	3.5	7.9
Prior Service Cost	$ 1	$ 0.9

EMPLOYEE BENEFITS - Schedule _6

EMPLOYEE BENEFITS - Schedule of Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2021USD ($)
Pension Plan
Defined Contribution Plan Disclosure [Line Items]
2022	$ 359.6
2023	367.4
2024	405
2025	381.2
2026	384.3
2027 - 2031	1,918.2
Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
2022	56.4
2023	56.2
2024	55.9
2025	55.3
2026	54.3
2027 - 2031	$ 254.6

EMPLOYEE BENEFITS - Schedule _7

EMPLOYEE BENEFITS - Schedule of Long-term Rates of Return on Pension and PBOP (Details)	Dec. 31, 2021	Dec. 31, 2020
United States
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	15.00%	15.00%
Assumed Rate of Return	8.50%	8.50%
Global
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	10.00%	10.00%
Assumed Rate of Return	8.75%	8.75%
Non-United States
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	8.00%	8.00%
Assumed Rate of Return	8.50%	8.50%
Emerging Markets
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	4.00%	4.00%
Assumed Rate of Return	10.00%	10.00%
Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	13.00%	13.00%
Assumed Rate of Return	4.00%	4.00%
Public High Yield Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	4.00%	4.00%
Assumed Rate of Return	6.50%	6.50%
Private Debt
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	13.00%	15.00%
Assumed Rate of Return	9.00%	9.00%
Private Equity
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	18.00%	15.00%
Assumed Rate of Return	12.00%	12.00%
Real Assets
Defined Contribution Plan Disclosure [Line Items]
Target Asset Allocation	15.00%	16.00%
Assumed Rate of Return	7.50%	7.50%

EMPLOYEE BENEFITS - Schedule _8

EMPLOYEE BENEFITS - Schedule of Asset Category (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 6,495.5	$ 5,409.2	$ 4,968.6
Uncategorized	5,479.8	4,480.4
Pension Plan | Total Assets Before 401
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	6,794	5,671.1
Pension Plan | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	2,107.7	1,952.5
Uncategorized	1,385.2	1,321.7
Pension Plan | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	2,062.5	1,781.7
Uncategorized	1,689.1	1,402.5
Pension Plan | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	1,702.7	1,197.7
Uncategorized	1,702.7	1,175.4
Pension Plan | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	921.1	739.2
Uncategorized	702.8	580.8
Pension Plan | 401 PBOP Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	(298.5)	(261.9)
Pension Plan | Level 1
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	1,080.4	925.1
Pension Plan | Level 1 | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	722.5	630.8
Pension Plan | Level 1 | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	139.6	113.6
Pension Plan | Level 1 | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	22.3
Pension Plan | Level 1 | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	218.3	158.4
Pension Plan | Level 2
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	233.8	265.6
Pension Plan | Level 2 | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Pension Plan | Level 2 | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	233.8	265.6
Pension Plan | Level 2 | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Pension Plan | Level 2 | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Other Postretirement Benefits Plan
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	1,138.3	1,004.1	$ 935.9
Uncategorized	463.5	424.4
Other Postretirement Benefits Plan | Total Assets Before 401
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	839.8	742.2
Other Postretirement Benefits Plan | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	439.7	394.3
Uncategorized	248.3	217.8
Other Postretirement Benefits Plan | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	220.4	212.1
Uncategorized	125.5	152.9
Other Postretirement Benefits Plan | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	58.7	31.5
Uncategorized	58.7	31.5
Other Postretirement Benefits Plan | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	121	104.3
Uncategorized	31	22.2
Other Postretirement Benefits Plan | 401 PBOP Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	298.5	261.9
Other Postretirement Benefits Plan | Level 1
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	331.1	274.6
Other Postretirement Benefits Plan | Level 1 | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	191.4	176.5
Other Postretirement Benefits Plan | Level 1 | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	49.7	16
Other Postretirement Benefits Plan | Level 1 | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Other Postretirement Benefits Plan | Level 1 | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	90	82.1
Other Postretirement Benefits Plan | Level 2
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	45.2	43.2
Other Postretirement Benefits Plan | Level 2 | Equity securities
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Other Postretirement Benefits Plan | Level 2 | Fixed Income
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	45.2	43.2
Other Postretirement Benefits Plan | Level 2 | Private Equity
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	0	0
Other Postretirement Benefits Plan | Level 2 | Real Assets
Defined Contribution Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 0	$ 0

EMPLOYEE BENEFITS - Defined Con

EMPLOYEE BENEFITS - Defined Contribution Plan Narrative (Details)	12 Months Ended
	Dec. 31, 2021
Defined Contribution Plan, 401K
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution (as a percentage)	100.00%
Percentage of employees' pay (up to)	3.00%
Defined Contribution Plan, Alternate Contribution 401K
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution (as a percentage)	50.00%
Percentage of employees' pay (up to)	8.00%

EMPLOYEE BENEFITS - Schedule _9

EMPLOYEE BENEFITS - Schedule of Defined Contribution Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	$ 55.5	$ 49.4	$ 41.6
The Connecticut Light and Power Company
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	7	6.6	5.5
NSTAR Electric Company
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	12.2	11.8	10.3
Public Service Company of New Hampshire
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	$ 4.3	$ 4.1	$ 3.5

EMPLOYEE BENEFITS - Share-Based

EMPLOYEE BENEFITS - Share-Based Payments Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in incentive plan (up to) (in shares)	6,700,000
Shares available for issuance under incentive plan (in shares)	2,430,716	2,876,601
Shares outstanding (in shares)	297,270
Weighted average grant date fair value of restricted stock units (in dollars per share)	$ 72.37
Total unrecognized compensation expense	$ 17.8
Period for recognition	1 year 8 months 19 days
Tax effect on total share-based payments (in percentage)	26.00%
Excess stock benefit	$ 4	$ 6.6	$ 1.5
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share)	$ 81.89	$ 88.23	$ 67.91
Shares outstanding (in shares)		379,258
Weighted average shares outstanding (in dollars per share)	$ 83.39	$ 77.13
Restricted stock units available (in shares)	219,560
Restricted stock unit fully vested (in shares)	297,353
Additional restricted stock unit expected to vest (in shares)	282,407
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share)	$ 76.08	$ 75.36	$ 68.33
Shares outstanding (in shares)	436,957	404,698
Weighted average shares outstanding (in dollars per share)	$ 81.41	$ 70.85
Restricted stock units available (in shares)	241,949
Weighted average grant date fair value of restricted stock units (in dollars per share)	$ 57.23
Restricted stock unit fully vested (in shares)	27,550
The Connecticut Light and Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense	$ 3.2
Excess stock benefit	1.5	$ 2.3	$ 0.5
NSTAR Electric Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense	5
Excess stock benefit	1.4	2.3	0.5
Public Service Company of New Hampshire
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense	1.1
Excess stock benefit	$ 0.5	$ 0.8	$ 0.2
Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of graded vesting schedule under long-term incentive program	3 years
Board Members
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of graded vesting schedule under long-term incentive program	1 year

EMPLOYEE BENEFITS - Summary o_2

EMPLOYEE BENEFITS - Summary of RSU and Share Transactions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock Units (RSUs)
Units
Beginning balance (in shares)	674,218
Granted (in shares)	165,930
Shares issued (in shares)	(223,484)
Forfeited (in shares)	(22,041)
Ending balance (in shares)	594,623	674,218
Weighted Average Grant-Date Fair Value
Beginning balance (in dollars per share)	$ 63.42
Granted (in dollars per share)	81.89	$ 88.23	$ 67.91
Shares issued (in dollars per share)	69.03
Forfeited (in dollars per share)	83.86
Ending balance (in dollars per share)	$ 65.70	$ 63.42
Performance Shares
Units
Beginning balance (in shares)	447,805
Granted (in shares)	286,645
Shares issued (in shares)	(256,914)
Forfeited (in shares)	(13,029)
Ending balance (in shares)	464,507	447,805
Weighted Average Grant-Date Fair Value
Beginning balance (in dollars per share)	$ 69.93
Granted (in dollars per share)	76.08	$ 75.36	$ 68.33
Shares issued (in dollars per share)	56.88
Forfeited (in dollars per share)	84.28
Ending balance (in dollars per share)	$ 80.54	$ 69.93

EMPLOYEE BENEFITS - Schedule_10

EMPLOYEE BENEFITS - Schedule of Compensation Expense and Income Tax Benefit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	$ 28.2	$ 33.9	$ 27.3
Future Income Tax Benefit	7.3	8.9	7
The Connecticut Light and Power Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	8.8	10.9	9.8
Future Income Tax Benefit	2.3	2.9	2.5
NSTAR Electric Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	9	11.3	9.7
Future Income Tax Benefit	2.3	3	2.5
Public Service Company of New Hampshire
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Expense	3	3.6	3.3
Future Income Tax Benefit	$ 0.8	$ 1	$ 0.8

EMPLOYEE BENEFITS - Schedule_11

EMPLOYEE BENEFITS - Schedule of Other Retirement Benefits (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarially-Determined Liability	$ 42.8	$ 45.7	$ 52
Other Retirement Benefits Expense	2.2	3.3	2.7
The Connecticut Light and Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarially-Determined Liability	0.2	0.2	0.2
Other Retirement Benefits Expense	0.7	1.2	1
NSTAR Electric Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarially-Determined Liability	0.1	0.1	0.1
Other Retirement Benefits Expense	0.7	1.1	0.9
Public Service Company of New Hampshire
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarially-Determined Liability	1.5	1.7	1.7
Other Retirement Benefits Expense	$ 0.3	$ 0.5	$ 0.4

INCOME TAXES - Components of In

INCOME TAXES - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current Income Taxes:
Federal	$ 21,500	$ 73,600	$ 56,900
State	(21,600)	19,100	10,500
Total Current	(100)	92,700	67,400
Deferred Income Taxes, Net:
Federal	199,700	173,500	138,400
State	147,400	83,700	71,400
Total Deferred	347,056	257,154	209,812
Investment Tax Credits, Net	(2,800)	(3,700)	(3,700)
Income Tax Expense	344,223	346,186	273,499
The Connecticut Light and Power Company
Current Income Taxes:
Federal	15,000	12,000	68,400
State	(7,000)	(6,100)	15,400
Total Current	8,000	5,900	83,800
Deferred Income Taxes, Net:
Federal	76,300	101,100	35,200
State	47,600	43,400	18,800
Total Deferred	123,889	144,527	54,005
Investment Tax Credits, Net	(600)	(700)	(800)
Income Tax Expense	131,273	149,702	136,971
NSTAR Electric Company
Current Income Taxes:
Federal	52,300	53,900	82,600
State	6,200	6,900	18,200
Total Current	58,500	60,800	100,800
Deferred Income Taxes, Net:
Federal	16,300	33,800	100
State	41,200	38,800	27,000
Total Deferred	57,507	72,595	27,107
Investment Tax Credits, Net	(1,700)	(2,600)	(2,600)
Income Tax Expense	114,335	130,828	125,313
Public Service Company of New Hampshire
Current Income Taxes:
Federal	43,100	20,600	22,900
State	10,800	3,800	2,200
Total Current	53,900	24,400	25,100
Deferred Income Taxes, Net:
Federal	(14,900)	(1,300)	5,800
State	400	8,600	10,100
Total Deferred	(14,530)	7,337	15,917
Investment Tax Credits, Net	0	0	0
Income Tax Expense	$ 39,433	$ 31,680	$ 40,975

INCOME TAXES - Reconciliation B

INCOME TAXES - Reconciliation Between Income Tax Expense and Expected Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Income Before Income Tax Expense	$ 1,572,269	$ 1,558,872	$ 1,190,071
Statutory Federal Income Tax Expense at 21%	330,200	327,400	249,900
Tax Effect of Differences:
Depreciation	(18,100)	(11,100)	1,900
Investment Tax Credit Amortization	(2,800)	(3,700)	(3,700)
State Income Taxes, Net of Federal Impact	54,400	44,900	24,600
Dividends on ESOP	(5,100)	(5,100)	(5,100)
Tax Asset Valuation   Allowance/Reserve Adjustments	44,600	33,400	40,100
Excess Stock Benefit	(4,000)	(6,600)	(1,500)
EDIT Amortization	(69,100)	(48,700)	(37,400)
Other, Net	14,100	15,700	4,700
Income Tax Expense	$ 344,223	$ 346,186	$ 273,499
Effective Tax Rate	21.90%	22.20%	23.00%
The Connecticut Light and Power Company
Income Tax Contingency [Line Items]
Income Before Income Tax Expense	$ 532,998	$ 607,636	$ 547,823
Statutory Federal Income Tax Expense at 21%	111,900	127,600	115,000
Tax Effect of Differences:
Depreciation	(6,400)	400	(200)
Investment Tax Credit Amortization	(600)	(700)	(800)
State Income Taxes, Net of Federal Impact	(4,600)	(1,200)	2,500
Tax Asset Valuation   Allowance/Reserve Adjustments	36,700	30,700	24,500
Excess Stock Benefit	(1,500)	(2,300)	(500)
EDIT Amortization	(9,800)	(9,000)	(5,800)
Other, Net	5,600	4,200	2,300
Income Tax Expense	$ 131,273	$ 149,702	$ 136,971
Effective Tax Rate	24.60%	24.60%	25.00%
NSTAR Electric Company
Income Tax Contingency [Line Items]
Income Before Income Tax Expense	$ 590,904	$ 575,829	$ 557,269
Statutory Federal Income Tax Expense at 21%	124,100	120,900	117,000
Tax Effect of Differences:
Depreciation	(3,400)	(3,700)	(3,000)
Investment Tax Credit Amortization	(1,700)	(2,600)	(2,600)
State Income Taxes, Net of Federal Impact	37,500	36,000	35,700
Tax Asset Valuation   Allowance/Reserve Adjustments	0	0	0
Excess Stock Benefit	(1,400)	(2,300)	(500)
EDIT Amortization	(43,200)	(20,400)	(22,900)
Other, Net	2,400	2,900	1,600
Income Tax Expense	$ 114,335	$ 130,828	$ 125,313
Effective Tax Rate	19.30%	22.70%	22.50%
Public Service Company of New Hampshire
Income Tax Contingency [Line Items]
Income Before Income Tax Expense	$ 189,771	$ 178,992	$ 175,023
Statutory Federal Income Tax Expense at 21%	39,900	37,600	36,800
Tax Effect of Differences:
Depreciation	(200)	(1,400)	(800)
Investment Tax Credit Amortization	0	0	0
State Income Taxes, Net of Federal Impact	8,900	9,800	9,800
Tax Asset Valuation   Allowance/Reserve Adjustments	0	0	0
Excess Stock Benefit	(500)	(800)	(200)
EDIT Amortization	(10,500)	(15,400)	(4,000)
Other, Net	1,800	1,900	(600)
Income Tax Expense	$ 39,433	$ 31,680	$ 40,975
Effective Tax Rate	20.80%	17.70%	23.40%

INCOME TAXES - Temporary Differ

INCOME TAXES - Temporary Differences That Give Rise To Accumulated Deferred Income Tax Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred Tax Assets:
Employee Benefits	$ 270.8	$ 602.4
Derivative Liabilities	76.8	92.6
Regulatory Deferrals - Liabilities	390.7	259.8
Allowance for Uncollectible Accounts	104.1	87.5
Tax Effect - Tax Regulatory Liabilities	783.4	810.9
Net Operating Loss Carryforwards	7.5	12.7
Purchase Accounting Adjustment	67.2	54.5
Other	196.6	200.3
Total Deferred Tax Assets	1,897.1	2,120.7
Less:  Valuation Allowance	61.5	48.3
Net Deferred Tax Assets	1,835.6	2,072.4
Deferred Tax Liabilities:
Accelerated Depreciation and Other   Plant-Related Differences	4,426	4,153.6
Property Tax Accruals	88.1	88.7
Regulatory Amounts:
Regulatory Deferrals - Assets	1,260.3	1,376.7
Tax Effect - Tax Regulatory Assets	257.8	244.6
Goodwill Regulatory Asset - 1999 Merger	81.4	86
Derivative Assets	14.9	17.8
Other	304.2	200.3
Total Deferred Tax Liabilities	6,432.7	6,167.7
The Connecticut Light and Power Company
Deferred Tax Assets:
Employee Benefits	23.9	144.5
Derivative Liabilities	76.8	91.8
Regulatory Deferrals - Liabilities	90.9	30.2
Allowance for Uncollectible Accounts	48.8	42.3
Tax Effect - Tax Regulatory Liabilities	328.2	331.4
Net Operating Loss Carryforwards	0	0
Purchase Accounting Adjustment	0	0
Other	103.9	100.9
Total Deferred Tax Assets	672.5	741.1
Less:  Valuation Allowance	44.5	33.7
Net Deferred Tax Assets	628	707.4
Deferred Tax Liabilities:
Accelerated Depreciation and Other   Plant-Related Differences	1,509.5	1,438.1
Property Tax Accruals	40.5	39
Regulatory Amounts:
Regulatory Deferrals - Assets	438.3	444.8
Tax Effect - Tax Regulatory Assets	181.4	174.4
Goodwill Regulatory Asset - 1999 Merger	0	0
Derivative Assets	14.9	17.8
Other	5.5	1.6
Total Deferred Tax Liabilities	2,190.1	2,115.7
NSTAR Electric Company
Deferred Tax Assets:
Employee Benefits	40.3	79.8
Derivative Liabilities	0	0
Regulatory Deferrals - Liabilities	215.4	161.8
Allowance for Uncollectible Accounts	21.5	20.9
Tax Effect - Tax Regulatory Liabilities	254.3	271.8
Net Operating Loss Carryforwards	0	0
Purchase Accounting Adjustment	0	0
Other	21.7	14.3
Total Deferred Tax Assets	553.2	548.6
Less:  Valuation Allowance	0	0
Net Deferred Tax Assets	553.2	548.6
Deferred Tax Liabilities:
Accelerated Depreciation and Other   Plant-Related Differences	1,553.7	1,489.4
Property Tax Accruals	33.7	37
Regulatory Amounts:
Regulatory Deferrals - Assets	337.6	324.4
Tax Effect - Tax Regulatory Assets	10.9	11.3
Goodwill Regulatory Asset - 1999 Merger	69.9	73.8
Derivative Assets	0	0
Other	126.9	72.6
Total Deferred Tax Liabilities	2,132.7	2,008.5
Public Service Company of New Hampshire
Deferred Tax Assets:
Employee Benefits	14.1	56.6
Derivative Liabilities	0	0
Regulatory Deferrals - Liabilities	24.3	13.4
Allowance for Uncollectible Accounts	6.2	4.6
Tax Effect - Tax Regulatory Liabilities	100.9	105.2
Net Operating Loss Carryforwards	0	0
Purchase Accounting Adjustment	0	0
Other	22.9	19.8
Total Deferred Tax Assets	168.4	199.6
Less:  Valuation Allowance	0	0
Net Deferred Tax Assets	168.4	199.6
Deferred Tax Liabilities:
Accelerated Depreciation and Other   Plant-Related Differences	482.9	453.8
Property Tax Accruals	6.3	5.8
Regulatory Amounts:
Regulatory Deferrals - Assets	198.4	263.4
Tax Effect - Tax Regulatory Assets	8.3	8.6
Goodwill Regulatory Asset - 1999 Merger	0	0
Derivative Assets	0	0
Other	10.5	5.6
Total Deferred Tax Liabilities	$ 706.4	$ 737.2

INCOME TAXES - Tax Credits and

INCOME TAXES - Tax Credits and Loss Carryforwards (Details) - State and Local Jurisdiction - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Federal and State Tax Credit	$ 197.7	$ 186.6
Operating Loss Carryforwards	138.3	183.4
Federal and State Charitable Contribution	23.7	10.2
The Connecticut Light and Power Company
Operating Loss Carryforwards [Line Items]
Federal and State Tax Credit	137	133.4
Operating Loss Carryforwards	0	0
Federal and State Charitable Contribution	0	0
NSTAR Electric Company
Operating Loss Carryforwards [Line Items]
Federal and State Tax Credit	0	0
Operating Loss Carryforwards	0	0
Federal and State Charitable Contribution	0	0
Public Service Company of New Hampshire
Operating Loss Carryforwards [Line Items]
Federal and State Tax Credit	0	0
Operating Loss Carryforwards	0	0
Federal and State Charitable Contribution	$ 0	$ 0

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Tax liability related to the deferral of employer payroll tax liability provision of the CARES Act	$ 19.6	$ 39
Accrued interest payable	0.1	0.1
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Valuation allowance for tax credit and operating loss carryforward	61.5	48.3
State and Local Jurisdiction | The Connecticut Light and Power Company
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	10.8	8.8
Eversource | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 13	$ 10.3

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Unrecognized Tax Benefit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 61.8	$ 55	$ 45.9
Gross Increases - Current Year	11.3	11.9	12.1
Gross Increases - Prior Year		1.4	3.4
Gross Decreases - Prior Year	(0.3)
Lapse of Statute of Limitations	(7)	(6.5)	(6.4)
Ending Balance	65.8	61.8	55
The Connecticut Light and Power Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	25.8	23.1	18.2
Gross Increases - Current Year	3.8	4.6	4
Gross Increases - Prior Year		0.7	3.3
Gross Decreases - Prior Year	(0.6)
Lapse of Statute of Limitations	(2.8)	(2.6)	(2.4)
Ending Balance	$ 26.2	$ 25.8	$ 23.1

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Schedule of Reconciliation of Activity in Environmental Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual for Environmental Loss Contingencies, Beginning Balance	$ 102.4	$ 81
Increase Due to CMA Asset Acquisition		22.9
Additions	23.4	8.4
Payments/Reductions	(10.4)	(9.9)
Accrual for Environmental Loss Contingencies, Ending Balance	115.4	102.4
The Connecticut Light and Power Company
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual for Environmental Loss Contingencies, Beginning Balance	12.3	11.4
Increase Due to CMA Asset Acquisition		0
Additions	4.4	4.2
Payments/Reductions	(2.8)	(3.3)
Accrual for Environmental Loss Contingencies, Ending Balance	13.9	12.3
NSTAR Electric Company
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual for Environmental Loss Contingencies, Beginning Balance	4.7	8
Increase Due to CMA Asset Acquisition		0
Additions	0	0.7
Payments/Reductions	(1.4)	(4)
Accrual for Environmental Loss Contingencies, Ending Balance	3.3	4.7
Public Service Company of New Hampshire
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual for Environmental Loss Contingencies, Beginning Balance	7.1	7.5
Increase Due to CMA Asset Acquisition		0
Additions	0	0
Payments/Reductions	(0.8)	(0.4)
Accrual for Environmental Loss Contingencies, Ending Balance	$ 6.3	$ 7.1

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Number of Sites and Reserves (Details) - site	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Number of Sites	61	63
The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Number of Sites	14	15
NSTAR Electric Company
Loss Contingencies [Line Items]
Number of Sites	11	12
Public Service Company of New Hampshire
Loss Contingencies [Line Items]
Number of Sites	9	9

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Environmental Matters Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)site	Dec. 31, 2020USD ($)site	Dec. 31, 2019USD ($)
Loss Contingencies [Line Items]
Number of sites | site	61	63
Reserve	$ 115.4	$ 102.4	$ 81
The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Number of sites | site	14	15
Reserve	$ 13.9	$ 12.3	11.4
NSTAR Electric Company
Loss Contingencies [Line Items]
Number of sites | site	11	12
Reserve	$ 3.3	$ 4.7	8
Public Service Company of New Hampshire
Loss Contingencies [Line Items]
Number of sites | site	9	9
Reserve	$ 6.3	$ 7.1	$ 7.5
MGP Site accrual
Loss Contingencies [Line Items]
Reserve balances related to former MGP sites	$ 105.6	$ 92.2
Environmental Sites for Which a Range of Loss Exists
Loss Contingencies [Line Items]
Number of sites | site	7
Reserve	$ 25.9
Best estimate of potential remediation costs (up to)	$ 10
Environmental Sites for Which a Range of Loss Exists | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Number of sites | site	2
Reserve	$ 3.2
Best estimate of potential remediation costs (up to)	$ 0.6
Environmental Site for Which a Range is Too Early to Determine
Loss Contingencies [Line Items]
Number of sites | site	13
Reserve	$ 16.1
Environmental Site for Which a Range is Too Early to Determine | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Number of sites | site	7
Reserve	$ 3.9
Environmental Site for Which a Range is Too Early to Determine | NSTAR Electric Company
Loss Contingencies [Line Items]
Number of sites | site	2
Reserve	$ 0.2
Evironmental Sites with Best Estimate
Loss Contingencies [Line Items]
Number of sites | site	41
Reserve	$ 73.4
Evironmental Sites with Best Estimate | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Reserve	$ 6.8
Environmental site quantity remaining | site	5
Evironmental Sites with Best Estimate | NSTAR Electric Company
Loss Contingencies [Line Items]
Reserve	$ 3.1
Environmental site quantity remaining | site	9
Evironmental Sites with Best Estimate | Public Service Company of New Hampshire
Loss Contingencies [Line Items]
Reserve	$ 6.3
Environmental site quantity remaining | site	9

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Schedule of Estimated Future Annual Costs of Long term Contractual Agreement (Details) $ in Millions	Dec. 31, 2021USD ($)
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	$ 1,251.4
2023	1,168.1
2024	1,113.6
2025	1,118.4
2026	1,020.1
Thereafter	5,184.3
Total	10,855.9
Renewable Energy
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	755.4
2023	700.7
2024	696.4
2025	718.7
2026	714.3
Thereafter	3,571.4
Total	7,156.9
Natural Gas Procurement
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	377.9
2023	323.6
2024	270.5
2025	265.5
2026	250.4
Thereafter	1,517.2
Total	3,005.1
Purchased Power and Capacity
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	76
2023	87.1
2024	86.7
2025	75.1
2026	2.9
Thereafter	9.8
Total	337.6
Peaker CfDs
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	26.1
2023	38.9
2024	39.4
2025	36.7
2026	29.9
Thereafter	63.3
Total	234.3
Transmission Support Commitments
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
2022	16
2023	17.8
2024	20.6
2025	22.4
2026	22.6
Thereafter	22.6
Total	122
The Connecticut Light and Power Company
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	690.7
2023	721.4
2024	723.3
2025	711.7
2026	630.8
Thereafter	2,824.4
Total	6,302.3
The Connecticut Light and Power Company | Renewable Energy
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	586.2
2023	592.1
2024	592
2025	593.9
2026	591.9
Thereafter	2,752.2
Total	5,708.3
The Connecticut Light and Power Company | Purchased Power and Capacity
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	72.1
2023	83.4
2024	83.8
2025	72.3
2026	0.1
Thereafter	0
Total	311.7
The Connecticut Light and Power Company | Peaker CfDs
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	26.1
2023	38.9
2024	39.4
2025	36.7
2026	29.9
Thereafter	63.3
Total	234.3
The Connecticut Light and Power Company | Transmission Support Commitments
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
2022	6.3
2023	7
2024	8.1
2025	8.8
2026	8.9
Thereafter	8.9
Total	48
NSTAR Electric Company
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	112.2
2023	88.2
2024	86.7
2025	87.8
2026	88.1
Thereafter	511
Total	974
NSTAR Electric Company | Renewable Energy
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	102.9
2023	78.3
2024	75.7
2025	76.1
2026	76.4
Thereafter	492.3
Total	901.7
NSTAR Electric Company | Purchased Power and Capacity
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	3
2023	2.9
2024	2.9
2025	2.8
2026	2.8
Thereafter	9.8
Total	24.2
NSTAR Electric Company | Transmission Support Commitments
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
2022	6.3
2023	7
2024	8.1
2025	8.9
2026	8.9
Thereafter	8.9
Total	48.1
Public Service Company of New Hampshire
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	70.6
2023	34.9
2024	33.1
2025	53.4
2026	50.8
Thereafter	331.7
Total	574.5
Public Service Company of New Hampshire | Renewable Energy
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	66.3
2023	30.3
2024	28.7
2025	48.7
2026	46
Thereafter	326.9
Total	546.9
Public Service Company of New Hampshire | Purchased Power and Capacity
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2022	0.9
2023	0.8
2024	0
2025	0
2026	0
Thereafter	0
Total	1.7
Public Service Company of New Hampshire | Transmission Support Commitments
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
2022	3.4
2023	3.8
2024	4.4
2025	4.7
2026	4.8
Thereafter	4.8
Total	$ 25.9

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES - Long-Term Contractual Arrangement Narrative (Details) MWh in Millions, $ in Millions	Oct. 31, 2020	Nov. 22, 2019megawatt	Mar. 15, 2019megawatt	Dec. 28, 2018MWh	Dec. 31, 2021USD ($)contractMW
Long-term Purchase Commitment [Line Items]
Estimated cost of energy purchase contracts					$ 10,855.9
Contract term					20 years
Construction in Progress
Long-term Purchase Commitment [Line Items]
Total construction contract cost					$ 6,700
Minimum
Long-term Purchase Commitment [Line Items]
Estimated costs under construction contract					150
Maximum
Long-term Purchase Commitment [Line Items]
Estimated costs under construction contract					415
Peaker Contracts For Differences
Long-term Purchase Commitment [Line Items]
Estimated cost of energy purchase contracts					$ 234.3
Percentage of costs and benefits borne by United Illuminated Company					20.00%
Period of payment to generation facility owner					30 years
The Connecticut Light and Power Company
Long-term Purchase Commitment [Line Items]
Estimated cost of energy purchase contracts					$ 6,302.3
The Connecticut Light and Power Company | Peaker Contracts For Differences
Long-term Purchase Commitment [Line Items]
Estimated cost of energy purchase contracts					$ 234.3
Number of capacity contracts | contract					3
Amount of peaking capacity contracts (in MW) | MW					500
Percentage of costs and benefits borne					80.00%
CL&P, NSTAR Electric and PSNH | Transmission Support Commitments
Long-term Purchase Commitment [Line Items]
Period of payment of annual operation and maintenance expense	20 years				30 years
Millstone Nuclear Power Station and Seabrook Nuclear Power Plant
Long-term Purchase Commitment [Line Items]
Estimated cost of energy purchase contracts					$ 3,300
Milestone Nuclear Power Station
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 MW) | megawatt			2,112
Milestone Nuclear Power Station | The Connecticut Light and Power Company
Long-term Purchase Commitment [Line Items]
Contract term				10 years
Percent of the facility's output required to be purchased			40.00%
Milestone Nuclear Power Station | UI
Long-term Purchase Commitment [Line Items]
Contract term				10 years
Seabrook Nuclear Power Plant
Long-term Purchase Commitment [Line Items]
Percent of the facility's output required to be purchased		18.00%
Nameplate capacity (in MW) | megawatt		1,250
Seabrook Nuclear Power Plant | The Connecticut Light and Power Company
Long-term Purchase Commitment [Line Items]
Contract term				8 years
Percent of the facility's output required to be purchased		15.00%
Seabrook Nuclear Power Plant | UI
Long-term Purchase Commitment [Line Items]
Contract term				8 years

COMMITMENTS AND CONTINGENCIES_6

COMMITMENTS AND CONTINGENCIES - Schedule of Total Costs Incurred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Long-term Purchase Commitment [Line Items]
Renewable Energy	$ 609.2	$ 584.2	$ 320.8
Natural Gas Procurement	712.7	453.4	448.5
Purchased Power and Capacity	56.4	62.7	62.1
Peaker CfDs	24.3	22.7	13
Transmission Support Commitments	15.4	22.1	21.8
The Connecticut Light and Power Company
Long-term Purchase Commitment [Line Items]
Renewable Energy	457.1	426.3	160.6
Purchased Power and Capacity	53.1	59.3	50.4
Peaker CfDs	24.3	22.7	13
Transmission Support Commitments	6.1	8.7	8.6
NSTAR Electric Company
Long-term Purchase Commitment [Line Items]
Renewable Energy	84.7	88.8	89.9
Purchased Power and Capacity	3	3.1	5.1
Peaker CfDs	0	0	0
Transmission Support Commitments	6	8.7	8.6
Public Service Company of New Hampshire
Long-term Purchase Commitment [Line Items]
Renewable Energy	67.4	69.1	70.3
Purchased Power and Capacity	0.3	0.3	6.6
Peaker CfDs	0	0	0
Transmission Support Commitments	$ 3.3	$ 4.7	$ 4.6

COMMITMENTS AND CONTINGENCIES_7

COMMITMENTS AND CONTINGENCIES - Spent Nuclear Fuel Obligations Narrative (Details) - USD ($) $ in Thousands	Mar. 25, 2021	Jun. 12, 2019	Feb. 21, 2019	May 22, 2017	Dec. 31, 2019	Jul. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Net of damages awarded		$ 500
Remaining damages sought		$ 1,000
Damages paid						$ 500
DOE settlement payment					$ 29,000		$ 0	$ 0	$ (29,000)
Yankee Companies
Guarantor Obligations [Line Items]
Damages sought	$ 120,400			$ 104,400
YAEC
Guarantor Obligations [Line Items]
Net of damages awarded					2,800
Total amount of damages awarded					5,400
MYAPC
Guarantor Obligations [Line Items]
Net of damages awarded					5,000
Total amount of damages awarded					$ 21,000
CYAPC, YAEC, And MYAPC
Guarantor Obligations [Line Items]
Net of damages awarded			$ 103,200
CYAPC
Guarantor Obligations [Line Items]
Net of damages awarded			40,700
YAEC
Guarantor Obligations [Line Items]
Net of damages awarded			28,100
MYAPC
Guarantor Obligations [Line Items]
Net of damages awarded			$ 34,400

COMMITMENTS AND CONTINGENCIES_8

COMMITMENTS AND CONTINGENCIES - Schedule of Guarantees and Indemnifications (Details) - USD ($)	Mar. 31, 2022	Jan. 31, 2022	Dec. 31, 2021	Oct. 25, 2019
Guarantor Obligations [Line Items]
Fair value of guarantees			$ 7,300,000
North East Offshore LLC
Guarantor Obligations [Line Items]
Ownership interest			50.00%
Sunrise Wind LLC
Guarantor Obligations [Line Items]
Maximum Exposure			$ 420,600,000	$ 15,400,000
Ownership interest			50.00%	50.00%
Revolution Wind, LLC
Guarantor Obligations [Line Items]
Maximum Exposure			$ 158,900,000
Ownership interest			50.00%
Construction-related Purchase Contracts with Third-Party Suppliers | South Fork Wind, LLC
Guarantor Obligations [Line Items]
Ownership interest			50.00%
North East Offshore LLC | Construction-related Purchase Contracts with Third-Party Suppliers
Guarantor Obligations [Line Items]
Maximum Exposure			$ 1,080,600,000
North East Offshore LLC | Performance Guarantee
Guarantor Obligations [Line Items]
Maximum Exposure			$ 1,300,000,000
Percent of obligations guaranteed			50.00%
North East Offshore LLC | Payment Guarantee
Guarantor Obligations [Line Items]
Maximum Exposure			$ 62,500,000
Percent of obligations guaranteed			50.00%
Sunrise Wind LLC | Construction-related Purchase Contracts with Third-Party Suppliers
Guarantor Obligations [Line Items]
Maximum Exposure			$ 382,300,000
Sunrise Wind LLC | OREC Capacity Production
Guarantor Obligations [Line Items]
Maximum Exposure			2,200,000
Revolution Wind, LLC | Construction-related Purchase Contracts with Third-Party Suppliers
Guarantor Obligations [Line Items]
Maximum Exposure			150,900,000
South Fork Wind, LLC | Letter of Credit | Subsequent Event
Guarantor Obligations [Line Items]
Borrowings outstanding	$ 43,400,000	$ 4,300,000
South Fork Wind, LLC | Construction-related Purchase Contracts with Third-Party Suppliers
Guarantor Obligations [Line Items]
Maximum Exposure			137,200,000
South Fork Wind, LLC | Transmission Interconnection
Guarantor Obligations [Line Items]
Maximum Exposure			1,200,000
South Fork Wind, LLC | Purchase Guarantee Expiring 2026
Guarantor Obligations [Line Items]
Maximum Exposure			$ 125,200,000
Eversource Investment LLC | North East Offshore LLC
Guarantor Obligations [Line Items]
Ownership interest			50.00%
Eversource Investment LLC | Funding and Indemnification Obligations
Guarantor Obligations [Line Items]
Maximum Exposure			$ 0
Eversource Investment LLC | Funding and Indemnification Obligations | North East Offshore LLC
Guarantor Obligations [Line Items]
Maximum Exposure			910,000,000
Bay State Wind LLC | Real Estate Purchase
Guarantor Obligations [Line Items]
Maximum Exposure			2,500,000
Various | Surety Bonds
Guarantor Obligations [Line Items]
Maximum Exposure			54,700,000
Eversource Service | Lease Payments for Real Estate
Guarantor Obligations [Line Items]
Maximum Exposure			$ 800,000

COMMITMENTS AND CONTINGENCIES_9

COMMITMENTS AND CONTINGENCIES - Guarantees and Obligations Narrative (Details) - USD ($)	Dec. 31, 2021	Sep. 16, 2020
Loss Contingencies [Line Items]
Fair value of guarantees	$ 7,300,000
Letter of Credit | Eversource Investment LLC
Loss Contingencies [Line Items]
Maximum borrowing capacity		$ 25,000,000

COMMITMENTS AND CONTINGENCIE_10

COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints (Details) $ in Millions	Oct. 16, 2018complaint	Apr. 29, 2016complaint	Dec. 31, 2021USD ($)	Apr. 14, 2017	Oct. 15, 2014	Dec. 31, 2020USD ($)	Jul. 31, 2014complaint
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified	10.41%
Percentage of incentive cap on total ROE	13.08%
FERC ROE Complaints
Loss Contingencies [Line Items]
Loss contingency, pending claims, number | complaint	4	4
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 First, Second and Third Complaints
Loss Contingencies [Line Items]
Loss contingency, pending claims, number | complaint							3
Base ROE percentage challenged by complainants			11.14%
Percentage of ROE for any incentive project	13.08%
FERC ROE First Complaint
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project				11.74%
Refund payments			$ 38.9
FERC ROE Second Complaint
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period			10.57%	10.57%
Percentage of ROE for any incentive project			11.74%
Loss contingency, estimate of possible earnings impact			$ 39.1
FERC ROE Fourth Complaint
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period		10.57%
Maximum percentage cap of ROE for incentive projects		11.74%
Percentage of ROE for any incentive project			10.57%
Original base ROE authorized by FERC at time of complaint			11.74%
The Connecticut Light and Power Company | FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments			$ 22.4
The Connecticut Light and Power Company | FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			21.4			$ 21.4
NSTAR Electric Company | FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments			13.7
NSTAR Electric Company | FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			14.6			14.6
Public Service Company of New Hampshire | FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments			2.8
Public Service Company of New Hampshire | FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact			$ 3.1			$ 3.1
Minimum | FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project					11.14%
Maximum | FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project					13.10%

COMMITMENTS AND CONTINGENCIE_11

COMMITMENTS AND CONTINGENCIES - Eversource and NSTAR Electric Boston Harbor Civil Action (Details) $ in Millions	Jul. 15, 2016kV	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Site Contingency [Line Items]
Amount of capacity required for installation of distribution cable (in kV) | kV	115
Asset retirement obligations		$ 500.1	$ 499.7	$ 489.5
NSTAR Electric Company
Site Contingency [Line Items]
Asset retirement obligations		$ 97.5	$ 91.8	$ 97.5

COMMITMENTS AND CONTINGENCIE_12

COMMITMENTS AND CONTINGENCIES - CL&P Tropical Storm Isaias Response Investigation (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2021	Jul. 14, 2021	May 07, 2021	May 06, 2021	Apr. 28, 2021
Loss Contingencies [Line Items]
Loss contingency, allowed rate of ROE					9.25%
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				$ 30
Loss contingency, estimate of possible earnings impact, accident reporting violation fines				$ 1.6
Non-compliance fine		$ 28.6
Loss contingency, accident reporting violation fines		$ 0.2
Loss contingency, penalty rate as a percent of distribution revenues			2.50%
Loss contingency, after-tax earnings impact per share (in dollars per share)	$ (0.25)	$ 0.07

COMMITMENTS AND CONTINGENCIE_13

COMMITMENTS AND CONTINGENCIES - CL&P Comprehensive Settlement Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 01, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 14, 2021
Loss Contingencies [Line Items]
Regulatory Liabilities		$ 602,432	$ 389,430
Loss related to litigation settlement		81,274	0	$ 0
Basis points reduction to return on equity, scenario one	0.90%
Basis points reduction to return on equity, scenario two	0.45%
The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Regulatory Liabilities		266,489	137,166
Loss related to litigation settlement		81,274	$ 0	$ 0
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Loss related to litigation settlement		103,600
Customer credits and assistance	$ 75,000
Loss related to litigation settlement, net of tax		$ 86,100
Loss contingency, after-tax earnings impact per share (in dollars per share)		$ 0.25			$ (0.07)
Unfavorable Regulatory Action | Sales
Loss Contingencies [Line Items]
Loss related to litigation settlement		$ 65,000
Unfavorable Regulatory Action | Oil and Gas, Operation and Maintenance
Loss Contingencies [Line Items]
Loss related to litigation settlement		10,000
Unfavorable Regulatory Action | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Customer credits	65,000
Customer assistance initiatives	$ 10,000
Regulatory Liabilities		75,000
Unfavorable Regulatory Action | The Connecticut Light and Power Company | Sales
Loss Contingencies [Line Items]
Loss related to litigation settlement		$ 65,000

LEASES - Narrative (Details)

LEASES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	$ 2.1	$ 0.6	$ 2.9
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 2.3	0.7	2
CMA
Lessee, Lease, Description [Line Items]
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities		14.7
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities		54.2
Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
The Connecticut Light and Power Company
Lessee, Lease, Description [Line Items]
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	$ 0	0.1	1
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	0	0
The Connecticut Light and Power Company | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
The Connecticut Light and Power Company | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
NSTAR Electric Company
Lessee, Lease, Description [Line Items]
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	$ 1.9	0.2	0.1
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	0.3	0
NSTAR Electric Company | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
NSTAR Electric Company | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years
Public Service Company of New Hampshire
Lessee, Lease, Description [Line Items]
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	$ 0	0	0.2
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0	$ 0
Public Service Company of New Hampshire | Minimum
Lessee, Lease, Description [Line Items]
Renewal period	1 year
Public Service Company of New Hampshire | Maximum
Lessee, Lease, Description [Line Items]
Renewal period	20 years

LEASES - Components of Lease Co

LEASES - Components of Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Amortization of Right-of-use-Assets	$ 4.6	$ 2.6	$ 1.7
Interest on Lease Liabilities	3.9	1.4	1.2
Total Finance Lease Cost	8.5	4	2.9
Operating Lease Cost	12.2	11.1	11.7
Variable Lease Cost	61	57.8	60.5
Total Lease Cost	81.7	72.9	75.1
The Connecticut Light and Power Company
Lease, Cost [Abstract]
Amortization of Right-of-use-Assets	0.5	0.7	0.7
Interest on Lease Liabilities	0.1	0.3	0.6
Total Finance Lease Cost	0.6	1	1.3
Operating Lease Cost	0.3	0.6	0.5
Variable Lease Cost	16.2	12.2	13.3
Total Lease Cost	17.1	13.8	15.1
NSTAR Electric Company
Lease, Cost [Abstract]
Amortization of Right-of-use-Assets	0.2	0.2	0.2
Interest on Lease Liabilities	0.6	0.6	0.6
Total Finance Lease Cost	0.8	0.8	0.8
Operating Lease Cost	2.3	2.1	3.4
Variable Lease Cost	0	0	0
Total Lease Cost	3.1	2.9	4.2
Public Service Company of New Hampshire
Lease, Cost [Abstract]
Amortization of Right-of-use-Assets	0.1	0.1	0.1
Interest on Lease Liabilities	0	0	0
Total Finance Lease Cost	0.1	0.1	0.1
Operating Lease Cost	0.1	0.1	0.1
Variable Lease Cost	44.8	45.6	47.2
Total Lease Cost	$ 45	$ 45.8	$ 47.4

LEASES - Supplemental Balance S

LEASES - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating Leases:
Right-of-use-Assets, Net	$ 47.2	$ 55.2
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Long-Term Assets	Other Long-Term Assets
Current Portion	$ 10	$ 9.5
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Long-Term	$ 37.2	$ 45.7
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Long-Term Liabilities	Other Long-Term Liabilities
Total Operating Lease Liabilities	$ 47.2	$ 55.2
Finance Leases:
Right-of-use-Assets, Net	$ 58	$ 60.5
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Current Portion	$ 3.9	$ 5
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Current Liabilities	Other Current Liabilities
Long-Term	$ 55.4	$ 57.6
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Long-Term Liabilities	Other Long-Term Liabilities
Total Finance Lease Liabilities	$ 59.3	$ 62.6
The Connecticut Light and Power Company
Operating Leases:
Right-of-use-Assets, Net	0.1	0.3
Current Portion	0.1	0.2
Long-Term	0	0.1
Total Operating Lease Liabilities	0.1	0.3
Finance Leases:
Right-of-use-Assets, Net	0	0.7
Current Portion	0	1.4
Long-Term	0	0
Total Finance Lease Liabilities	0	1.4
NSTAR Electric Company
Operating Leases:
Right-of-use-Assets, Net	24.3	23.6
Current Portion	1.1	0.7
Long-Term	23.2	22.9
Total Operating Lease Liabilities	24.3	23.6
Finance Leases:
Right-of-use-Assets, Net	3.3	3.5
Current Portion	0	0
Long-Term	4.9	4.8
Total Finance Lease Liabilities	4.9	4.8
Public Service Company of New Hampshire
Operating Leases:
Right-of-use-Assets, Net	0.3	0.3
Current Portion	0	0
Long-Term	0.3	0.3
Total Operating Lease Liabilities	0.3	0.3
Finance Leases:
Right-of-use-Assets, Net	0.7	0.8
Current Portion	0.1	0.1
Long-Term	0.6	0.7
Total Finance Lease Liabilities	$ 0.7	$ 0.8

LEASES - Other Information Rela

LEASES - Other Information Related to Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Weighted-Average Remaining Lease Term (Years):
Operating Leases	13 years	10 years
Finance Leases	16 years	17 years
Weighted-Average Discount Rate (Percentage):
Operating Leases	4.10%	4.00%
Finance Leases	2.70%	2.90%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 12.1	$ 10.9	$ 11.4
Operating Cash Flows from Finance Leases	3.4	1.7	1.2
Financing Cash Flows from Finance Leases	4.1	2.8	2.6
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	2.1	0.6	2.9
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 2.3	$ 0.7	2
The Connecticut Light and Power Company
Weighted-Average Remaining Lease Term (Years):
Operating Leases	7 years	3 years
Finance Leases		1 year
Weighted-Average Discount Rate (Percentage):
Operating Leases	3.00%	2.40%
Finance Leases	0.00%	10.50%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 0.3	$ 0.6	0.4
Operating Cash Flows from Finance Leases	0.1	0.3	0.6
Financing Cash Flows from Finance Leases	1.4	1.6	1.4
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0	0.1	1
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0	0
NSTAR Electric Company
Weighted-Average Remaining Lease Term (Years):
Operating Leases	18 years	19 years
Finance Leases	20 years	21 years
Weighted-Average Discount Rate (Percentage):
Operating Leases	4.00%	4.10%
Finance Leases	2.90%	2.90%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 2.1	$ 1.8	1.6
Operating Cash Flows from Finance Leases	0.6	0.6	0.6
Financing Cash Flows from Finance Leases	0	0	0
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	1.9	0.2	0.1
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0.3	0
Public Service Company of New Hampshire
Weighted-Average Remaining Lease Term (Years):
Operating Leases	7 years	8 years
Finance Leases	7 years	8 years
Weighted-Average Discount Rate (Percentage):
Operating Leases	3.70%	3.70%
Finance Leases	3.50%	3.50%
Cash Paid for Amounts Included in the Measurement of Lease Liabilities:
Operating Cash Flows from Operating Leases	$ 0.1	$ 0.1	0.1
Operating Cash Flows from Finance Leases	0	0	0
Financing Cash Flows from Finance Leases	0.1	0.1	0.1
Supplemental Non-Cash Information on Lease Liabilities:
Right-of-use-Assets Obtained in Exchange for New Operating Lease Liabilities	0	0	0.2
Right-of-use-Assets Obtained in Exchange for New Finance Lease Liabilities	$ 0	$ 0	$ 0

LEASES - Future Minimum Lease P

LEASES - Future Minimum Lease Payments under Long-Term Leases (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2022	$ 11.1
2023	7.6
2024	6.1
2025	3.2
2026	2.5
Thereafter	27.8
Future lease payments	58.3
Less amount representing interest	11.1
Present value of future minimum lease payments	47.2	$ 55.2
Finance Leases
2022	6
2023	5.2
2024	5.3
2025	5.2
2026	4.7
Thereafter	56
Future lease payments	82.4
Less amount representing interest	23.1
Present value of future minimum lease payments	59.3	62.6
The Connecticut Light and Power Company
Operating Leases
2022	0.1
2023	0
2024	0
2025	0
2026	0
Thereafter	0
Future lease payments	0.1
Less amount representing interest	0
Present value of future minimum lease payments	0.1	0.3
Finance Leases
Present value of future minimum lease payments	0	1.4
NSTAR Electric Company
Operating Leases
2022	2.1
2023	2.1
2024	2.1
2025	1.7
2026	1.7
Thereafter	25.3
Future lease payments	35
Less amount representing interest	10.7
Present value of future minimum lease payments	24.3	23.6
Finance Leases
2022	0.6
2023	0.7
2024	0.7
2025	0.6
2026	0.6
Thereafter	12.4
Future lease payments	15.6
Less amount representing interest	10.7
Present value of future minimum lease payments	4.9	4.8
Public Service Company of New Hampshire
Operating Leases
2022	0.1
2023	0.1
2024	0
2025	0
2026	0
Thereafter	0.1
Future lease payments	0.3
Less amount representing interest	0
Present value of future minimum lease payments	0.3	0.3
Finance Leases
2022	0.1
2023	0.1
2024	0.1
2025	0.1
2026	0.1
Thereafter	0.3
Future lease payments	0.8
Less amount representing interest	0.1
Present value of future minimum lease payments	$ 0.7	$ 0.8

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
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	453,702	496,912
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	18,216,700	16,179,100
Rate Reduction Bonds	496,900	540,100
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	166,300	169,100
Long-Term Debt	19,636,300	18,420,100
Rate Reduction Bonds	543,300	603,400
The Connecticut Light and Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,200	116,200
The Connecticut Light and Power Company | 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	4,215,400	3,914,800
The Connecticut Light and Power Company | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	122,300	123,400
Long-Term Debt	4,848,900	4,800,900
NSTAR Electric Company
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 Company | 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	3,985,400	3,643,200
NSTAR Electric Company | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	44,000	45,700
Long-Term Debt	4,453,500	4,294,000
Public Service Company of New Hampshire
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Rate Reduction Bonds	453,702	496,912
Public Service Company of New Hampshire | 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	1,163,800	1,099,100
Rate Reduction Bonds	496,900	540,100
Public Service Company of New Hampshire | Fair Value
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	1,220,600	1,207,000
Rate Reduction Bonds	$ 543,300	$ 603,400

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) - Schedule of Changes in AOCI By Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 14,063,566	$ 12,629,994
OCI Before Reclassifications	23,400	(19,200)
Amounts Reclassified from AOCI	10,700	7,900
Net OCI	34,100	(11,300)
Ending balance	14,599,844	14,063,566
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(76,411)	(65,059)
Ending balance	(42,275)	(76,411)
Qualified Cash Flow Hedging Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,400)	(3,000)
OCI Before Reclassifications	0	0
Amounts Reclassified from AOCI	1,000	1,600
Net OCI	1,000	1,600
Ending balance	(400)	(1,400)
Unrealized Gains/(Losses) on Marketable Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	1,100	700
OCI Before Reclassifications	(700)	400
Amounts Reclassified from AOCI	0	0
Net OCI	(700)	400
Ending balance	400	1,100
Defined Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(76,100)	(62,800)
OCI Before Reclassifications	24,100	(19,600)
Amounts Reclassified from AOCI	9,700	6,300
Net OCI	33,800	(13,300)
Ending balance	$ (42,300)	$ (76,100)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Related tax effect recognized in AOCI	$ 8.3	$ 6	$ 4.4
Pre-tax amount reclassified from AOCI as a decrease to net income	0.1
NSTAR Electric Company
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pre-tax amount reclassified from AOCI as a decrease to net income	$ 0.1

ACCUMULATED OTHER COMPREHENSI_5

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) - Schedule of Amounts Reclassified From AOCI By Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax Effect	$ (344,223)	$ (346,186)	$ (273,499)
Net Income Attributable to Common Shareholders	1,220,527	1,205,167	909,053
Defined Benefit Plan Costs:
Total Amounts Reclassified from AOCI, Net of Tax	(10,700)	(7,900)	(7,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax Effect	700	900	1,100
Qualified Cash Flow Hedging Instruments, Net of Tax | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income Attributable to Common Shareholders	(1,000)	(1,600)	(1,400)
Amortization of Actuarial Losses
Defined Benefit Plan Costs:
Reclassifications from AOCI	(13,100)	(8,100)	(5,700)
Amortization of Prior Service Credit/(Cost)
Defined Benefit Plan Costs:
Reclassifications from AOCI	0	(300)	(1,800)
Defined Benefit Plans
Defined Benefit Plan Costs:
Reclassifications from AOCI	(13,100)	(8,400)	(7,500)
Tax Effect	3,400	2,100	1,900
Total Amounts Reclassified from AOCI, Net of Tax	(9,700)	(6,300)	(5,600)
Interest Expense | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Qualified Cash Flow Hedging Instruments	$ (1,700)	$ (2,500)	$ (2,500)

DIVIDEND RESTRICTIONS (Details)

DIVIDEND RESTRICTIONS (Details) $ in Millions	Dec. 31, 2021USD ($)
Schedule of Restrictions on Retained Earnings [Line Items]
Consolidated total debt to total capital ratio (as a percentage)	0.65
Retained earnings subject to restrictions	$ 5,010
The Connecticut Light and Power Company
Schedule of Restrictions on Retained Earnings [Line Items]
Retained earnings subject to restrictions	2,230
NSTAR Electric Company
Schedule of Restrictions on Retained Earnings [Line Items]
Retained earnings subject to restrictions	2,720
Public Service Company of New Hampshire
Schedule of Restrictions on Retained Earnings [Line Items]
Retained earnings subject to restrictions	$ 504.6

COMMON SHARES - Common Shares A

COMMON SHARES - Common Shares Authorized and Issued (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Per share par value (in dollars per share)	$ 5	$ 5	$ 5
Authorized (in shares)	380,000,000	380,000,000
Issued (in shares)	357,818,402	357,818,402
The Connecticut Light and Power Company
Class of Stock [Line Items]
Per share par value (in dollars per share)	$ 10	$ 10
Authorized (in shares)	24,500,000	24,500,000
Issued (in shares)	6,035,205	6,035,205
NSTAR Electric Company
Class of Stock [Line Items]
Per share par value (in dollars per share)	$ 1	$ 1
Authorized (in shares)	100,000,000	100,000,000
Issued (in shares)	200	200
Public Service Company of New Hampshire
Class of Stock [Line Items]
Per share par value (in dollars per share)	$ 1	$ 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	Dec. 01, 2021	Apr. 08, 2021	Jun. 15, 2020	Mar. 26, 2020	Mar. 23, 2020	Dec. 30, 2019	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Equity offering (in shares)			6,000,000					5,980,000
Price per share (in dollars per share)			$ 86.26
Net proceeds from common shares issued directly by the Company			$ 509,200	$ 314,100	$ 105,700				$ 929,000	$ 852,300	$ 0	$ 928,992	$ 852,254
Common shares issuable pursuant to forward sale agreement (in shares)			11,960,000	4,460,000	1,500,000								6,000,000
Forward sale price (in dollars per share)						$ 71.48
Common shares issued directly by the Company (in shares)							5,960,000
Treasury stock (in shares)											13,415,206	14,864,379
Common stock outstanding (in shares)											344,403,196	342,954,023
Issuance of Treasury Shares for Acquisition of New England Service Company	$ 38,100	$ 38,051
Common Shares
Equity [Abstract]
Common shares issued directly by the Company (in shares)												11,960,000	11,980,000
Common stock outstanding (in shares)										329,880,645	344,403,196	342,954,023	329,880,645	316,885,808
Class of Stock [Line Items]
Issuance of Treasury Shares for Acquisition of New England Service Company (in shares)	462,517

PREFERRED STOCK NOT SUBJECT T_3

PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION - Narrative (Details)	Dec. 31, 2021$ / sharesshares
The Connecticut Light and Power Company
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares) | shares	9,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 50
NSTAR Electric Company
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares) | shares	2,890,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 100

PREFERRED STOCK NOT SUBJECT T_4

PREFERRED STOCK NOT SUBJECT TO MANDATORY REDEMPTION - Schedule of Preferred Stock by Class (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Preferred stock value outstanding	$ 155.6	$ 155.6
The Connecticut Light and Power Company
Class of Stock [Line Items]
Shares outstanding (in shares)	2,324,000	2,324,000
Preferred stock value outstanding	$ 116.2	$ 116.2
The Connecticut Light and Power Company | Series of 1947 Preferred Stock at $1.90
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 1,900,000	$ 1,900,000
Redemption Price Per Share (in dollars per share)	$ 52.50
Shares outstanding (in shares)	163,912	163,912
Preferred stock value outstanding	$ 8.2	$ 8.2
The Connecticut Light and Power Company | Series of 1947 Preferred Stock at $2.00
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 2,000,000	$ 2,000,000
Redemption Price Per Share (in dollars per share)	$ 54
Shares outstanding (in shares)	336,088	336,088
Preferred stock value outstanding	$ 16.8	$ 16.8
The Connecticut Light and Power Company | Series of 1949 Preferred Stock at $2.04
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 2,040,000	$ 2,040,000
Redemption Price Per Share (in dollars per share)	$ 52
Shares outstanding (in shares)	100,000	100,000
Preferred stock value outstanding	$ 5	$ 5
The Connecticut Light and Power Company | Series of 1949 Preferred Stock at $2.20
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 2,200,000	$ 2,200,000
Redemption Price Per Share (in dollars per share)	$ 52.50
Shares outstanding (in shares)	200,000	200,000
Preferred stock value outstanding	$ 10	$ 10
The Connecticut Light and Power Company | Series of 1949 Preferred Stock at 3.90%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	3.90%	3.90%
Redemption Price Per Share (in dollars per share)	$ 50.50
Shares outstanding (in shares)	160,000	160,000
Preferred stock value outstanding	$ 8	$ 8
The Connecticut Light and Power Company | Series E of 1954 Preferred Stock at $2.06
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 2,060,000	$ 2,060,000
Redemption Price Per Share (in dollars per share)	$ 51
Shares outstanding (in shares)	200,000	200,000
Preferred stock value outstanding	$ 10	$ 10
The Connecticut Light and Power Company | Series F of 1955 Preferred Stock at $2.09
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 2,090,000	$ 2,090,000
Redemption Price Per Share (in dollars per share)	$ 51
Shares outstanding (in shares)	100,000	100,000
Preferred stock value outstanding	$ 5	$ 5
The Connecticut Light and Power Company | Series of 1956 Preferred Stock at 4.5%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	4.50%	4.50%
Redemption Price Per Share (in dollars per share)	$ 50.75
Shares outstanding (in shares)	104,000	104,000
Preferred stock value outstanding	$ 5.2	$ 5.2
The Connecticut Light and Power Company | Series of 1958 Preferred Stock at 4.96%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	4.96%	4.96%
Redemption Price Per Share (in dollars per share)	$ 50.50
Shares outstanding (in shares)	100,000	100,000
Preferred stock value outstanding	$ 5	$ 5
The Connecticut Light and Power Company | Series of 1963 Preferred Stock at 4.5%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	4.50%	4.50%
Redemption Price Per Share (in dollars per share)	$ 50.50
Shares outstanding (in shares)	160,000	160,000
Preferred stock value outstanding	$ 8	$ 8
The Connecticut Light and Power Company | Series of 1967 Preferred Stock at 5.28%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	5.28%	5.28%
Redemption Price Per Share (in dollars per share)	$ 51.43
Shares outstanding (in shares)	200,000	200,000
Preferred stock value outstanding	$ 10	$ 10
The Connecticut Light and Power Company | Series G of 1968 Preferred Stock at $3.24
Class of Stock [Line Items]
Preferred stock, dividend rate, per-dollar-amount (in dollars per share)	$ 3,240,000	$ 3,240,000
Redemption Price Per Share (in dollars per share)	$ 51.84
Shares outstanding (in shares)	300,000	300,000
Preferred stock value outstanding	$ 15	$ 15
The Connecticut Light and Power Company | Series of 1968 Preferred Stock at 6.56%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	6.56%	6.56%
Redemption Price Per Share (in dollars per share)	$ 51.44
Shares outstanding (in shares)	200,000	200,000
Preferred stock value outstanding	$ 10	$ 10
NSTAR Electric Company
Class of Stock [Line Items]
Shares outstanding (in shares)	430,000	430,000
Preferred stock value outstanding	$ 43	$ 43
NSTAR Electric Company | Preferred Stock 4.25%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	4.25%	4.25%
Redemption Price Per Share (in dollars per share)	$ 103.625
Shares outstanding (in shares)	180,000	180,000
Preferred stock value outstanding	$ 18	$ 18
NSTAR Electric Company | Preferred Stock 4.78%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	4.78%	4.78%
Redemption Price Per Share (in dollars per share)	$ 102.80
Shares outstanding (in shares)	250,000	250,000
Preferred stock value outstanding	$ 25	$ 25
Aquarion Water Company | Series of Preferred Stock at 6%
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percentage)	6.00%
Redemption Price Per Share (in dollars per share)	$ 100
Shares outstanding (in shares)	23	23
Preferred stock value outstanding	$ 0	$ 0
Fair Value Adjustment | NSTAR Electric Company
Class of Stock [Line Items]
Preferred stock value outstanding	$ 3.6	$ 3.6

COMMON SHAREHOLDERS' EQUITY A_2

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Net income attributable to noncontrolling interests	$ 7,500	$ 7,500	$ 7,500
Noncontrolling interest - preferred stock of subsidiaries	$ 155,570	$ 155,570

EARNINGS PER SHARE - Narrative

EARNINGS PER SHARE - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
Earnings Per Share [Abstract]
Antidilutive share awards excluded from the EPS computation (in shares)	39,560	0	0

EARNINGS PER SHARE - Components

EARNINGS PER SHARE - Components of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Income Attributable to Common Shareholders	$ 1,220,527	$ 1,205,167	$ 909,053
Weighted Average Common Shares Outstanding:
Basic (in shares)	343,972,926	338,836,147	321,416,086
Dilutive Effect of:
Share-Based Compensation Awards and Other (in shares)	658,130	738,994	762,215
Equity Forward Sale Agreement (in shares)	0	271,921	763,335
Dilutive Effect (in shares)	658,130	1,010,915	1,525,550
Diluted (in shares)	344,631,056	339,847,062	322,941,636
Basic EPS (in dollars per share)	$ 3.55	$ 3.56	$ 2.83
Diluted EPS (in dollars per share)	$ 3.54	$ 3.55	$ 2.81

REVENUES - Operating Revenues D

REVENUES - Operating Revenues Disaggregated by Revenue Source (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 9,815,000	$ 8,766,500	$ 8,450,000
Alternative Revenue Programs	41,700	130,000	53,200
Other Revenues	6,400	7,900	23,300
Operating Revenues	9,863,085	8,904,430	8,526,470
Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	5,123,600	4,741,500	4,411,100
Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,041,400	2,772,900	2,992,000
Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	499,700	425,600	421,600
Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	8,664,700	7,940,000	7,824,700
Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	453,200	340,900	269,400
Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	661,800	374,100	275,200
Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	114,000	111,500	80,700
Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(78,700)
The Connecticut Light and Power Company
Disaggregation of Revenue [Line Items]
Operating Revenues	3,637,412	3,547,527	3,232,551
NSTAR Electric Company
Disaggregation of Revenue [Line Items]
Operating Revenues	3,056,350	2,941,148	3,044,642
Public Service Company of New Hampshire
Disaggregation of Revenue [Line Items]
Operating Revenues	1,177,248	1,079,095	1,065,936
Operating Segments | Electric Distribution
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	7,404,000	7,038,600	6,912,100
Alternative Revenue Programs	14,700	88,100	45,900
Other Revenues	4,900	5,600	18,500
Operating Revenues	7,423,600	7,132,300	6,976,500
Operating Segments | Electric Distribution | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,989,800	3,951,500	3,723,700
Operating Segments | Electric Distribution | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	2,486,100	2,353,400	2,584,800
Operating Segments | Electric Distribution | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	345,300	327,100	331,800
Operating Segments | Electric Distribution | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	6,821,200	6,632,000	6,640,300
Operating Segments | Electric Distribution | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Distribution | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	575,800	327,300	215,700
Operating Segments | Electric Distribution | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	78,100	79,300	56,100
Operating Segments | Electric Distribution | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(71,100)
Operating Segments | Natural Gas Distribution
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,752,300	1,162,900	1,064,000
Alternative Revenue Programs	37,000	44,700	(4,900)
Other Revenues	300	1,100	3,100
Operating Revenues	1,789,600	1,208,700	1,062,200
Operating Segments | Natural Gas Distribution | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,000,300	644,900	555,100
Operating Segments | Natural Gas Distribution | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	497,600	361,900	347,600
Operating Segments | Natural Gas Distribution | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	167,200	107,400	96,900
Operating Segments | Natural Gas Distribution | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,665,100	1,114,200	999,600
Operating Segments | Natural Gas Distribution | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Natural Gas Distribution | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	82,100	43,000	55,400
Operating Segments | Natural Gas Distribution | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	5,100	5,700	9,000
Operating Segments | Natural Gas Distribution | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0
Operating Segments | Electric Transmission
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,759,900	1,570,600	1,306,500
Alternative Revenue Programs	(126,100)	(35,200)	81,800
Other Revenues	800	700	700
Operating Revenues	1,634,600	1,536,100	1,389,000
Operating Segments | Electric Transmission | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Transmission | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Transmission | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Transmission | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Transmission | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,751,300	1,557,300	1,293,300
Operating Segments | Electric Transmission | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Electric Transmission | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	13,600	13,300	13,200
Operating Segments | Electric Transmission | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(5,000)
Operating Segments | Water Distribution
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	209,400	219,600	209,000
Alternative Revenue Programs	1,500	(4,700)	4,600
Other Revenues	400	500	1,000
Operating Revenues	211,300	215,400	214,600
Operating Segments | Water Distribution | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	133,500	145,100	132,300
Operating Segments | Water Distribution | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	62,800	62,400	63,900
Operating Segments | Water Distribution | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,300	4,800	4,500
Operating Segments | Water Distribution | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	200,600	212,300	200,700
Operating Segments | Water Distribution | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Water Distribution | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,900	3,800	4,100
Operating Segments | Water Distribution | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	7,500	3,500	4,200
Operating Segments | Water Distribution | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(2,600)
Operating Segments | The Connecticut Light and Power Company
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	4,238,900	4,044,700	3,626,900
Alternative Revenue Programs	(78,900)	(4,200)	77,500
Other Revenues	400	2,200	10,300
Operating Segments | The Connecticut Light and Power Company | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,994,200	2,011,100	1,837,100
Operating Segments | The Connecticut Light and Power Company | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	890,600	878,300	922,900
Operating Segments | The Connecticut Light and Power Company | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	131,400	137,500	138,300
Operating Segments | The Connecticut Light and Power Company | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,016,200	3,026,900	2,898,300
Operating Segments | The Connecticut Light and Power Company | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	863,300	754,800	587,100
Operating Segments | The Connecticut Light and Power Company | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	408,800	230,100	105,100
Operating Segments | The Connecticut Light and Power Company | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	26,700	32,900	36,400
Operating Segments | The Connecticut Light and Power Company | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(76,100)	0	0
Operating Segments | NSTAR Electric Company
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	3,541,600	3,327,500	3,396,400
Alternative Revenue Programs	(15,100)	54,500	41,600
Other Revenues	3,400	3,500	7,000
Operating Segments | NSTAR Electric Company | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,375,800	1,365,800	1,322,100
Operating Segments | NSTAR Electric Company | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,265,000	1,176,800	1,349,400
Operating Segments | NSTAR Electric Company | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	119,100	106,400	115,800
Operating Segments | NSTAR Electric Company | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	2,759,900	2,649,000	2,787,300
Operating Segments | NSTAR Electric Company | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	616,300	576,500	517,300
Operating Segments | NSTAR Electric Company | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	109,200	58,400	73,100
Operating Segments | NSTAR Electric Company | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	56,200	43,600	18,700
Operating Segments | NSTAR Electric Company | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Operating Segments | Public Service Company of New Hampshire
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,387,600	1,241,300	1,200,100
Alternative Revenue Programs	(17,400)	2,600	8,600
Other Revenues	1,900	600	1,900
Operating Segments | Public Service Company of New Hampshire | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	619,800	574,600	564,500
Operating Segments | Public Service Company of New Hampshire | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	332,200	299,900	314,600
Operating Segments | Public Service Company of New Hampshire | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	94,800	83,200	77,700
Operating Segments | Public Service Company of New Hampshire | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,046,800	957,700	956,800
Operating Segments | Public Service Company of New Hampshire | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	271,700	226,000	188,900
Operating Segments | Public Service Company of New Hampshire | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	57,800	38,800	37,500
Operating Segments | Public Service Company of New Hampshire | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	11,300	14,200	15,600
Operating Segments | Public Service Company of New Hampshire | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	4,600	1,300
Other
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,354,000	1,235,900	1,028,500
Alternative Revenue Programs	0	0	0
Other Revenues	0	0	0
Operating Revenues	1,354,000	1,235,900	1,028,500
Other | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Other | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Other | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Other | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Other | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	86,600	74,200	61,300
Other | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Other | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1,267,400	1,161,700	967,200
Other | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0
Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(2,664,600)	(2,461,100)	(2,070,100)
Alternative Revenue Programs	114,600	37,100	(74,200)
Other Revenues	0	0	0
Operating Revenues	(2,550,000)	(2,424,000)	(2,144,300)
Eliminations | Residential
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Eliminations | Commercial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(5,100)	(4,800)	(4,300)
Eliminations | Industrial
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(17,100)	(13,700)	(11,600)
Eliminations | Total Retail Tariff Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(22,200)	(18,500)	(15,900)
Eliminations | Wholesale Transmission Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(1,384,700)	(1,290,600)	(1,085,200)
Eliminations | Wholesale Market Sales Revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0	0	0
Eliminations | Other Revenues from Contracts with Customers
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(1,257,700)	(1,152,000)	(969,000)
Eliminations | Reserve for Revenues Subject to Refund
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0
Consolidations Eliminations | The Connecticut Light and Power Company
Disaggregation of Revenue [Line Items]
Operating Revenues	(523,000)	(495,200)	(482,100)
Consolidations Eliminations | NSTAR Electric Company
Disaggregation of Revenue [Line Items]
Operating Revenues	(473,500)	(444,400)	(400,400)
Consolidations Eliminations | Public Service Company of New Hampshire
Disaggregation of Revenue [Line Items]
Operating Revenues	$ (194,900)	$ (165,400)	$ (144,700)

REVENUES - Narrative (Details)

REVENUES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 01, 2021	May 06, 2021
Loss Contingencies [Line Items]
Loss related to litigation settlement	$ 81,274	$ 0	$ 0
Revenues from Contracts with Customers	9,815,000	8,766,500	8,450,000
Lease revenue	4,800	4,300	4,400
The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Loss related to litigation settlement	81,274	0	0
Lease revenue	800	800	1,000
NSTAR Electric Company
Loss Contingencies [Line Items]
Lease revenue	3,100	2,700	2,700
Reserve for Revenues Subject to Refund
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	(78,700)
Operating Segments | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	4,238,900	4,044,700	3,626,900
Operating Segments | NSTAR Electric Company
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	3,541,600	3,327,500	3,396,400
Operating Segments | Reserve for Revenues Subject to Refund | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	(76,100)	0	0
Operating Segments | Reserve for Revenues Subject to Refund | NSTAR Electric Company
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	0	$ 0	$ 0
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Loss related to litigation settlement	103,600
Unfavorable Regulatory Action | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact, non-compliance with performance standards				$ 28,400	$ 28,400
Unfavorable Regulatory Action | Operating Segments | Reserve for Revenues Subject to Refund | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Revenues from Contracts with Customers	93,400
Sales | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Loss related to litigation settlement	65,000
Sales | Unfavorable Regulatory Action | The Connecticut Light and Power Company
Loss Contingencies [Line Items]
Loss related to litigation settlement	$ 65,000

SEGMENT INFORMATION - Narrative

SEGMENT INFORMATION - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)segment
Segment Reporting Information [Line Items]
Number of reportable segments	1
Yankee Gas, NSTAR Gas and EGMA
Segment Reporting Information [Line Items]
Amount of natural gas transmission purchased | $	$ 77.7
The Connecticut Light and Power Company
Segment Reporting Information [Line Items]
Number of reportable segments	1
NSTAR Electric Company
Segment Reporting Information [Line Items]
Number of reportable segments	1
Public Service Company of New Hampshire
Segment Reporting Information [Line Items]
Number of reportable segments	1

SEGMENT INFORMATION - Schedule

SEGMENT INFORMATION - Schedule of Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Depreciation and Amortization	(1,335,000)	(1,159,100)	(1,080,700)
Impairment of Northern Pass Transmission	0	0	(239,644)
Other Operating Expenses	(6,534,800)	(5,756,600)	(5,615,700)
Operating Income	1,993,321	1,988,734	1,590,491
Interest Expense	(582,334)	(538,452)	(533,197)
Interest Income	25,600	4,800	12,800
Other Income, Net	135,700	103,800	120,000
Income Tax (Expense)/Benefit	(344,223)	(346,186)	(273,499)
Net Income	1,228,046	1,212,686	916,572
Net Income Attributable to Noncontrolling Interests	(7,519)	(7,519)	(7,519)
Net Income Attributable to Common Shareholders	1,220,527	1,205,167	909,053
Total Assets (as of)	48,492,144	46,099,598
Cash Flows Used for Investments in Plant	3,175,080	2,942,996	2,911,489
Operating Segments | Electric Distribution
Segment Reporting Information [Line Items]
Operating Revenues	7,423,600	7,132,300	6,976,500
Depreciation and Amortization	(737,800)	(657,000)	(651,300)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(5,970,000)	(5,642,300)	(5,525,100)
Operating Income	715,800	833,000	800,100
Interest Expense	(236,400)	(216,000)	(206,400)
Interest Income	20,700	3,200	13,300
Other Income, Net	78,100	58,000	46,800
Income Tax (Expense)/Benefit	(103,500)	(129,600)	(135,900)
Net Income	474,700	548,600	517,900
Net Income Attributable to Noncontrolling Interests	(4,600)	(4,600)	(4,600)
Net Income Attributable to Common Shareholders	470,100	544,000	513,300
Total Assets (as of)	25,411,200	24,981,900
Cash Flows Used for Investments in Plant	1,053,300	1,079,000	1,104,200
Operating Segments | Natural Gas Distribution
Segment Reporting Information [Line Items]
Operating Revenues	1,789,600	1,208,700	1,062,200
Depreciation and Amortization	(142,300)	(87,900)	(68,300)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(1,345,400)	(913,800)	(830,800)
Operating Income	301,900	207,000	163,100
Interest Expense	(58,600)	(40,000)	(47,400)
Interest Income	4,500	900	100
Other Income, Net	17,900	3,100	1,600
Income Tax (Expense)/Benefit	(60,900)	(36,900)	(21,200)
Net Income	204,800	134,100	96,200
Net Income Attributable to Noncontrolling Interests	0	0	0
Net Income Attributable to Common Shareholders	204,800	134,100	96,200
Total Assets (as of)	7,215,900	6,450,500
Cash Flows Used for Investments in Plant	721,100	494,400	460,200
Operating Segments | Electric Transmission
Segment Reporting Information [Line Items]
Operating Revenues	1,634,600	1,536,100	1,389,000
Depreciation and Amortization	(300,300)	(278,100)	(253,300)
Impairment of Northern Pass Transmission			(239,600)
Other Operating Expenses	(496,200)	(470,000)	(411,200)
Operating Income	838,100	788,000	484,900
Interest Expense	(133,200)	(126,800)	(125,700)
Interest Income	2,200	4,700	1,500
Other Income, Net	19,800	23,300	29,200
Income Tax (Expense)/Benefit	(179,400)	(183,800)	(130,500)
Net Income	547,500	505,400	259,400
Net Income Attributable to Noncontrolling Interests	(2,900)	(2,900)	(2,900)
Net Income Attributable to Common Shareholders	544,600	502,500	256,500
Total Assets (as of)	12,377,800	11,695,000
Cash Flows Used for Investments in Plant	1,024,100	1,004,600	987,000
Operating Segments | Water Distribution
Segment Reporting Information [Line Items]
Operating Revenues	211,300	215,400	214,600
Depreciation and Amortization	(46,100)	(44,200)	(46,900)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(101,400)	(86,600)	(101,000)
Operating Income	63,800	84,600	66,700
Interest Expense	(32,000)	(32,900)	(34,600)
Interest Income	0	0	0
Other Income, Net	3,300	2,000	400
Income Tax (Expense)/Benefit	1,700	(12,500)	2,400
Net Income	36,800	41,200	34,900
Net Income Attributable to Noncontrolling Interests	0	0	0
Net Income Attributable to Common Shareholders	36,800	41,200	34,900
Total Assets (as of)	2,551,100	2,375,200
Cash Flows Used for Investments in Plant	137,200	118,800	118,000
Other
Segment Reporting Information [Line Items]
Operating Revenues	1,354,000	1,235,900	1,028,500
Depreciation and Amortization	(113,100)	(93,500)	(63,200)
Impairment of Northern Pass Transmission			0
Other Operating Expenses	(1,170,400)	(1,071,900)	(891,300)
Operating Income	70,500	70,500	74,000
Interest Expense	(168,800)	(161,000)	(170,300)
Interest Income	46,000	37,800	48,700
Other Income, Net	1,363,900	1,382,900	945,300
Income Tax (Expense)/Benefit	(2,100)	16,600	11,700
Net Income	1,309,500	1,346,800	909,400
Net Income Attributable to Noncontrolling Interests	0	0	0
Net Income Attributable to Common Shareholders	1,309,500	1,346,800	909,400
Total Assets (as of)	22,674,700	22,089,400
Cash Flows Used for Investments in Plant	239,400	246,200	242,100
Eliminations
Segment Reporting Information [Line Items]
Operating Revenues	(2,550,000)	(2,424,000)	(2,144,300)
Depreciation and Amortization	4,600	1,600	2,300
Impairment of Northern Pass Transmission			0
Other Operating Expenses	2,548,600	2,428,000	2,143,700
Operating Income	3,200	5,600	1,700
Interest Expense	46,600	38,300	51,200
Interest Income	(47,800)	(41,800)	(50,800)
Other Income, Net	(1,347,300)	(1,365,500)	(903,300)
Income Tax (Expense)/Benefit	0	0	0
Net Income	(1,345,300)	(1,363,400)	(901,200)
Net Income Attributable to Noncontrolling Interests	0	0	0
Net Income Attributable to Common Shareholders	(1,345,300)	(1,363,400)	(901,200)
Total Assets (as of)	(21,738,600)	(21,492,400)
Cash Flows Used for Investments in Plant	$ 0	$ 0	$ 0

ACQUISITION OF ASSETS OF COLU_3

ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS - Narrative (Details) - USD ($)	Oct. 01, 2021	Oct. 09, 2020	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Oct. 07, 2020
Business Acquisition [Line Items]
Operating revenues					$ 154,800,000
Pre-tax income					13,900,000
Impairment loss	$ 0
Acquisition of Assets of Columbia Gas of Massachusetts, Net of Restricted Cash				$ 0	(1,113,252,000)	$ 0
TSA
Business Acquisition [Line Items]
TSA and pre-TSA costs			$ 21,400,000	$ 15,900,000
Energy Efficiency expense			2,000,000
DPU
Business Acquisition [Line Items]
Approved rate base							$ 995,000,000
CMA
Business Acquisition [Line Items]
Consideration transferred		$ 1,100,000,000
Operating revenues					9,273,000,000	$ 9,103,000,000
Contingent liability for future refund to customers		6,700,000
Energy relief fund liability		$ 56,800,000
Arrearage Forgiveness Fund			$ 15,400,000		15,400,000
Acquisition of Assets of Columbia Gas of Massachusetts, Net of Restricted Cash					$ (1,110,000,000)

ACQUISITION OF ASSETS OF COLU_4

ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS - Preliminary Allocation of the Cash Purchase Price (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Oct. 09, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 4,477,269	$ 4,445,988		$ 4,427,000
CMA
Business Acquisition [Line Items]
Current Assets			$ 138,000
Restricted Cash			57,000
PP&E			1,182,000
Goodwill			52,000
Other Noncurrent Assets, excluding Goodwill			131,000
Other Current Liabilities			(81,000)
Other Noncurrent Liabilities			(310,000)
Cash Purchase Price			$ 1,169,000

ACQUISITION OF ASSETS OF COLU_5

ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS - Schedule of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Operating Revenues	$ 154.8
CMA
Business Acquisition [Line Items]
Operating Revenues	9,273	$ 9,103
Net Income Attributable to Common Shareholders	$ 1,265	$ 909
Basic EPS (in dollars per share)	$ 3.73	$ 2.83
Diluted EPS (in dollars per share)	$ 3.72	$ 2.82

GOODWILL - Narrative (Details)

GOODWILL - Narrative (Details) - USD ($)	Oct. 01, 2021	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill acquired		$ 21,000,000	$ 42,000,000
Goodwill measurement period adjustments		10,000,000
Goodwill disposed of			23,000,000
Impairment loss	$ 0
CMA
Goodwill [Line Items]
Goodwill acquired		51,900,000
Water Distribution
Goodwill [Line Items]
Goodwill acquired		21,700,000	0
Goodwill measurement period adjustments		0
Goodwill disposed of			23,000,000
Water Distribution | Hingham Water System
Goodwill [Line Items]
Goodwill disposed of		23,600,000
Water Distribution | CMA
Goodwill [Line Items]
Goodwill measurement period adjustments		9,600,000
Natural Gas Distribution
Goodwill [Line Items]
Goodwill acquired		0	42,000,000
Goodwill measurement period adjustments		$ 10,000,000
Goodwill disposed of			$ 0

GOODWILL - Summary of Goodwill

GOODWILL - Summary of Goodwill by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance	$ 4,445,988	$ 4,427,000
Goodwill acquired	21,000	42,000
Sale of Hingham water system		(23,000)
Goodwill measurement period adjustments	10,000
Balance	4,477,269	4,445,988
Electric Distribution
Goodwill [Roll Forward]
Balance	2,544,000	2,544,000
Goodwill acquired	0	0
Sale of Hingham water system		0
Goodwill measurement period adjustments	0
Balance	2,544,000	2,544,000
Electric Transmission
Goodwill [Roll Forward]
Balance	577,000	577,000
Goodwill acquired	0	0
Sale of Hingham water system		0
Goodwill measurement period adjustments	0
Balance	577,000	577,000
Water Distribution
Goodwill [Roll Forward]
Balance	884,000	907,000
Goodwill acquired	21,700	0
Sale of Hingham water system		(23,000)
Goodwill measurement period adjustments	0
Balance	905,000	884,000
Natural Gas Distribution
Goodwill [Roll Forward]
Balance	441,000	399,000
Goodwill acquired	0	42,000
Sale of Hingham water system		0
Goodwill measurement period adjustments	10,000
Balance	$ 451,000	$ 441,000

SCHEDULE I - FINANCIAL INFORM_2

SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEET (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current Assets:
Cash	$ 66,773	$ 106,599
Prepayments and Other Current Assets	369,759	252,439
Total Current Assets	3,270,120	3,130,143
Deferred Debits and Other Assets:
Investments in Subsidiary Companies, at Equity	1,436,293	1,107,143
Goodwill	4,477,269	4,445,988	$ 4,427,000
Other Long-Term Assets	883,756	583,854
Total Deferred Debits and Other Assets	11,844,374	12,086,932
Total Assets (as of)	48,492,144	46,099,598
Current Liabilities:
Notes Payable	1,505,450	1,249,325
Long-Term Debt – Current Portion	1,193,097	1,053,186
Other Current Liabilities	830,620	809,214
Total Current Liabilities	5,847,039	4,915,012
Deferred Credits and Other Liabilities	10,412,412	11,342,662
Capitalization:
Long-Term Debt	17,023,577	15,125,876
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid in	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Loss	(42,275)	(76,411)
Treasury Stock	(250,878)	(277,979)
Stockholders' equity	14,599,844	14,063,566	$ 12,629,994	$ 11,486,817
Total Liabilities and Capitalization	48,492,144	46,099,598
Eversource
Current Assets:
Cash	175	434
Accounts Receivable from Subsidiaries	43,403	39,645
Notes Receivable from Subsidiaries	1,245,900	996,300
Prepayments and Other Current Assets	11,974	19,043
Total Current Assets	1,301,452	1,055,422
Deferred Debits and Other Assets:
Investments in Subsidiary Companies, at Equity	16,108,190	15,483,263
Notes Receivable from Subsidiaries	1,001,000	1,110,400
Accumulated Deferred Income Taxes	17,409	33,469
Goodwill	3,852,524	3,231,811
Other Long-Term Assets	101,710	90,735
Total Deferred Debits and Other Assets	21,080,833	19,949,678
Total Assets (as of)	22,382,285	21,005,100
Current Liabilities:
Notes Payable	1,342,950	1,054,325
Long-Term Debt – Current Portion	767,681	473,933
Accounts Payable to Subsidiaries	37,609	18,424
Other Current Liabilities	87,745	103,477
Total Current Liabilities	2,235,985	1,650,159
Deferred Credits and Other Liabilities	150,616	163,053
Capitalization:
Long-Term Debt	5,395,840	5,128,322
Common Shareholders' Equity:
Common Shares	1,789,092	1,789,092
Capital Surplus, Paid in	8,098,514	8,015,663
Retained Earnings	5,005,391	4,613,201
Accumulated Other Comprehensive Loss	(42,275)	(76,411)
Treasury Stock	(250,878)	(277,979)
Stockholders' equity	14,599,844	14,063,566
Total Liabilities and Capitalization	$ 22,382,285	$ 21,005,100

SCHEDULE I - FINANCIAL INFORM_3

SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF INCOME (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Operating Revenues	$ 9,863,085	$ 8,904,430	$ 8,526,470
Operating Expenses:
Other	1,739,685	1,480,252	1,363,113
Operating Income (Loss)	1,993,321	1,988,734	1,590,491
Interest Expense	582,334	538,452	533,197
Other Income, Net:
Equity in Earnings of Subsidiaries	14,200	14,200	42,200
Other Income, Net	161,282	108,590	132,777
Income Before Income Tax Expense	1,572,269	1,558,872	1,190,071
Income Tax Benefit	344,223	346,186	273,499
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Basic Earnings Per Common Share (in dollars per share)	$ 3.55	$ 3.56	$ 2.83
Diluted Earnings Per Common Share (in dollars per share)	$ 3.54	$ 3.55	$ 2.81
Weighted Average Common Shares Outstanding:
Basic (in shares)	343,972,926	338,836,147	321,416,086
Diluted (in shares)	344,631,056	339,847,062	322,941,636
Eversource
Condensed Income Statements, Captions [Line Items]
Operating Revenues	$ 0	$ 0	$ 0
Operating Expenses:
Other	43,048	28,645	50,100
Operating Income (Loss)	(43,048)	(28,645)	(50,100)
Interest Expense	163,613	160,887	163,937
Other Income, Net:
Equity in Earnings of Subsidiaries	1,345,199	1,309,630	1,001,526
Other, Net	47,802	38,546	68,137
Other Income, Net	1,393,001	1,348,176	1,069,663
Income Before Income Tax Expense	1,186,340	1,158,644	855,626
Income Tax Benefit	(34,187)	(46,523)	(53,427)
Net Income	$ 1,220,527	$ 1,205,167	$ 909,053
Basic Earnings Per Common Share (in dollars per share)	$ 3.55	$ 3.56	$ 2.83
Diluted Earnings Per Common Share (in dollars per share)	$ 3.54	$ 3.55	$ 2.81
Weighted Average Common Shares Outstanding:
Basic (in shares)	343,972,926	338,836,147	321,416,086
Diluted (in shares)	344,631,056	339,847,062	322,941,636

SCHEDULE I - FINANCIAL INFORM_4

SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Statement of Income Captions [Line Items]
Net Income	$ 1,228,046	$ 1,212,686	$ 916,572
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Change in Funded Status of Pension, SERP and PBOP Benefit Plans	33,835	(13,290)	(7,618)
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income	1,254,663	1,193,815	903,994
Eversource
Condensed Statement of Income Captions [Line Items]
Net Income	1,220,527	1,205,167	909,053
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	972	1,596	1,393
Changes in Unrealized (Losses)/Gains on Marketable Securities	(671)	342	1,166
Change in Funded Status of Pension, SERP and PBOP Benefit Plans	33,835	(13,290)	(7,618)
Other Comprehensive Income/(Loss), Net of Tax	34,136	(11,352)	(5,059)
Comprehensive Income	$ 1,254,663	$ 1,193,815	$ 903,994

SCHEDULE I - FINANCIAL INFORM_5

SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - STATEMENT OF CASH FLOW (Details) - USD ($) $ in Thousands	Jun. 15, 2020	Mar. 26, 2020	Mar. 23, 2020	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income						$ 1,228,046	$ 1,212,686	$ 916,572
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Equity in Earnings of Subsidiaries						(14,200)	(14,200)	(42,200)
Deferred Income Taxes						347,056	257,154	209,812
Other						(64,640)	(25,957)	(42,610)
Accounts Receivables from Subsidiaries						(135,505)	(351,843)	(98,716)
Taxes Receivable/Accrued, Net						(110,621)	43,819	(16,129)
Other Current Assets and Liabilities, Net						5,569	(9,591)	(11,603)
Net Cash Flows Provided by Operating Activities						1,962,600	1,682,572	2,009,577
Investing Activities:
Other Investing Activities						22,178	23,809	24,204
Net Cash Flows Used in Investing Activities						(3,447,374)	(4,129,275)	(3,274,288)
Financing Activities:
Issuance of Common Shares, Net of Issuance Costs	$ 509,200	$ 314,100	$ 105,700	$ 929,000	$ 852,300	0	928,992	852,254
Cash Dividends on Common Shares						(805,439)	(744,665)	(663,239)
Issuance of Long-Term Debt						3,230,000	2,760,000	1,520,000
Retirement of Long-Term Debt						(1,142,500)	(327,236)	(801,078)
Other Financing Activities						(46,625)	14,273	(1,006)
Net Cash Flows Provided by Financing Activities						1,440,832	2,594,590	1,172,450
Net (Decrease)/Increase in Cash and Restricted Cash						(43,942)	147,887	(92,261)
Cash and Restricted Cash - Beginning of Year						264,950	117,063	209,324
Cash and Restricted Cash - End of Year					117,063	221,008	264,950	117,063
Cash Paid/(Received) During the Year for:
Interest						568,700	518,000	532,400
Income Taxes						121,600	48,900	56,000
Eversource
Operating Activities:
Net Income						1,220,527	1,205,167	909,053
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Equity in Earnings of Subsidiaries						(1,345,199)	(1,309,630)	(1,001,526)
Cash Dividends Received from Subsidiaries						1,037,100	485,800	883,000
Deferred Income Taxes						20,293	(4,667)	13,382
Other						36,910	39,940	19,584
Accounts Receivables from Subsidiaries						(3,758)	(14,575)	7,105
Taxes Receivable/Accrued, Net						(19,455)	35,300	(605)
Accounts Payable to Subsidiaries						19,185	14,091	(4,099)
Other Current Assets and Liabilities, Net						8,144	21,284	(2,503)
Net Cash Flows Provided by Operating Activities						973,747	472,710	823,391
Investing Activities:
Capital Contributions to Subsidiaries						(1,033,000)	(1,899,340)	(1,039,000)
Return of Capital from Subsidiaries						178,800	80,000	0
Increase in Notes Receivable from Subsidiaries						(140,200)	(264,300)	(218,100)
Other Investing Activities						(3,196)	(367)	(1,799)
Net Cash Flows Used in Investing Activities						(997,596)	(2,084,007)	(1,258,899)
Financing Activities:
Issuance of Common Shares, Net of Issuance Costs						0	928,992	852,254
Cash Dividends on Common Shares						(805,439)	(744,665)	(663,239)
Issuance of Long-Term Debt						1,000,000	1,550,000	0
Retirement of Long-Term Debt						(450,000)	0	(350,000)
(Decrease)/Increase in Notes Payable						288,625	(170,545)	593,370
Other Financing Activities						(9,545)	46,480	4,001
Net Cash Flows Provided by Financing Activities						23,641	1,610,262	436,386
Net (Decrease)/Increase in Cash and Restricted Cash						(208)	(1,035)	878
Cash and Restricted Cash - Beginning of Year						434	1,469	591
Cash and Restricted Cash - End of Year					$ 1,469	226	434	1,469
Cash Paid/(Received) During the Year for:
Interest						164,568	140,694	161,323
Income Taxes						$ (51,277)	$ (43,158)	$ (63,277)

SCHEDULE II - VALUATION AND Q_2

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Increase due to CMA acquisition		$ 24,200
Allowance for uncollectible accounts for late fees and other receivable amounts	$ 417,406	358,851	$ 224,800
Restatement Adjustment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for uncollectible accounts for late fees and other receivable amounts		23,800
The Connecticut Light and Power Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Period of accounts receivable recoverable under financial or medical duress	180 days
Increase due to CMA acquisition		0
Allowance for uncollectible accounts for late fees and other receivable amounts	$ 181,319	157,447	97,300
The Connecticut Light and Power Company | Restatement Adjustment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for uncollectible accounts for late fees and other receivable amounts		22,200
NSTAR Electric Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Increase due to CMA acquisition		0
Allowance for uncollectible accounts for late fees and other receivable amounts	97,005	91,583	75,400
NSTAR Electric Company | Restatement Adjustment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for uncollectible accounts for late fees and other receivable amounts		(1,300)
Public Service Company of New Hampshire
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Increase due to CMA acquisition		0
Allowance for uncollectible accounts for late fees and other receivable amounts	$ 24,331	17,157	10,500
Public Service Company of New Hampshire | Restatement Adjustment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for uncollectible accounts for late fees and other receivable amounts		300
Yankee Gas Services Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Period of accounts receivable recoverable under financial or medical duress	90 days
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 358,851	224,821	212,723
Additions, Charged to Costs and Expense	60,886	53,461	63,446
Additions, Charged to Other Accounts	110,572	145,005	57,223
Deductions	112,903	64,436	108,571
Balance at end of period	417,406	358,851	224,821
Allowance for Doubtful Accounts | The Connecticut Light and Power Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	157,447	97,348	88,034
Additions, Charged to Costs and Expense	13,495	12,882	15,947
Additions, Charged to Other Accounts	57,779	71,223	38,935
Deductions	47,402	24,006	45,568
Balance at end of period	181,319	157,447	97,348
Allowance for Doubtful Accounts | NSTAR Electric Company
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	91,583	75,406	74,516
Additions, Charged to Costs and Expense	16,649	15,293	25,079
Additions, Charged to Other Accounts	20,064	23,424	12,556
Deductions	31,291	22,540	36,745
Balance at end of period	97,005	91,583	75,406
Allowance for Doubtful Accounts | Public Service Company of New Hampshire
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	17,157	10,497	11,065
Additions, Charged to Costs and Expense	13,113	5,164	6,726
Additions, Charged to Other Accounts	3,135	7,692	872
Deductions	9,074	6,196	8,166
Balance at end of period	$ 24,331	$ 17,157	$ 10,497