SHORT-TERM DEBT (Tables)

12 Months Ended

Dec. 31, 2025

Debt Disclosure [Abstract]

Schedule of Borrowings Outstanding

The amount of borrowings outstanding and available under the commercial paper programs were as follows:

	Borrowings Outstanding  as of December 31,				Available Borrowing Capacity as of December 31,				Weighted-Average Interest Rate as of December 31,
(Millions of Dollars)	2025		2024		2025		2024		2025		2024
Eversource Parent Commercial Paper Program	$	1,280.0	$	1,538.0	$	720.0	$	462.0	3.98	%	4.76	%
NSTAR Electric Commercial Paper Program	245.4		504.8		404.6		145.2		3.87	%	4.55	%

Details of long-term debt outstanding are as follows:

CL&P (Millions of Dollars)			As of December 31,
	Interest Rate		2025		2024
First Mortgage Bonds:
2004 Series B due 2034	5.750	%	130.0		130.0
2005 Series B due 2035	5.625	%	100.0		100.0
2006 Series A due 2036	6.350	%	250.0		250.0
2007 Series B due 2037	5.750	%	150.0		150.0
2007 Series D due 2037	6.375	%	100.0		100.0
2014 Series A due 2044	4.300	%	475.0		475.0
2015 Series A due 2045	4.150	%	350.0		350.0
2017 Series A due 2027	3.200	%	500.0		500.0
2018 Series A due 2048	4.000	%	800.0		800.0
2020 Series A due 2025	0.750	%	—		400.0
2021 Series A due 2031	2.050	%	425.0		425.0
2023 Series A due 2053	5.250	%	500.0		500.0
2023 Series B due 2033	4.900	%	300.0		300.0
2024 Series A due 2029	4.650	%	350.0		350.0
2024 Series B due 2034	4.950	%	300.0		300.0
2025 Series A due 2030	4.950	%	400.0		—
Total First Mortgage Bonds			5,130.0		5,130.0
Less Amounts due Within One Year			—		(400.0)
Current Portion Classified as Long-Term Debt (1)			—		397.1
Unamortized Premiums and Discounts, Net			12.4		14.3
Unamortized Debt Issuance Costs			(32.3)		(33.2)
CL&P Long-Term Debt			$	5,110.1	$	5,108.2

NSTAR Electric (Millions of Dollars)			As of December 31,
	Interest Rate		2025		2024
Debentures:
2006 Debentures due 2036	5.750	%	$	200.0	$	200.0
2010 Debentures due 2040	5.500	%	300.0		300.0
2014 Debentures due 2044	4.400	%	300.0		300.0
2015 Debentures due 2025	3.250	%	—		250.0
2016 Debentures due 2026	2.700	%	250.0		250.0
2017 Debentures due 2027	3.200	%	700.0		700.0
2019 Debentures due 2029	3.250	%	400.0		400.0
2020 Debentures due 2030	3.950	%	400.0		400.0
2021 Debentures due 2051	3.100	%	300.0		300.0
2021 Debentures due 2031	1.950	%	300.0		300.0
2022 Debentures due 2052	4.550	%	450.0		450.0
2022 Debentures due 2052	4.950	%	400.0		400.0
2023 Debentures due 2028	5.600	%	150.0		150.0
2024 Debentures due 2034	5.400	%	600.0		600.0
2025 Debentures due 2030	4.850	%	400.0		—
2025 Debentures due 2035	5.200	%	700.0		—
Total Debentures			5,850.0		5,000.0
Notes:
2004 Senior Notes Series B due 2034	5.900	%	50.0		50.0
2007 Senior Notes Series D due 2037	6.700	%	40.0		40.0
2016 Senior Notes Series H due 2026	2.750	%	50.0		50.0
Total Notes			140.0		140.0
Less Amounts due Within One Year			(300.0)		(250.0)
Unamortized Premiums and Discounts, Net			(8.1)		(14.0)
Unamortized Debt Issuance Costs			(36.3)		(31.1)
NSTAR Electric Long-Term Debt			$	5,645.6	$	4,844.9

PSNH (Millions of Dollars)			As of December 31,
	Interest Rate		2025		2024
First Mortgage Bonds:
2005 Series M due 2035	5.600	%	$	50.0	$	50.0
2019 Series T due 2049	3.600	%	300.0		300.0
2020 Series U due 2050	2.400	%	150.0		150.0
2021 Series V due 2031	2.200	%	350.0		350.0
2023 Series W due 2053	5.150	%	300.0		300.0
2023 Series X due 2033	5.350	%	600.0		600.0
2025 Series Y due 2028	4.400	%	300.0		—
Total First Mortgage Bonds			2,050.0		1,750.0
Unamortized Premiums and Discounts, Net			(2.8)		(2.6)
Unamortized Debt Issuance Costs			(15.9)		(15.3)
PSNH Long-Term Debt			$	2,031.3	$	1,732.1

OTHER (Millions of Dollars)					As of December 31,
	Interest Rate				2025		2024
Eversource Parent - Senior Notes due 2026 - 2050	1.400	%	-	5.950%	$	11,350.0	$	11,350.0
Yankee Gas - First Mortgage Bonds due 2026 - 2051	1.380	%	-	5.740%	1,205.0		1,095.0
NSTAR Gas - First Mortgage Bonds due 2029 - 2051	2.250	%	-	7.110%	1,055.0		905.0
EGMA - First Mortgage Bonds due 2028 - 2052	2.110	%	-	5.730%	933.0		808.0
Aquarion - Unsecured Notes due 2028 - 2052	3.000	%	-	6.430%	596.6		596.8
Aquarion - Secured Debt due 2027 - 2045	1.296	%	-	9.290%	47.9		40.7
Pre-1983 Spent Nuclear Fuel Obligation (CYAPC)					5.9		5.6
Fair Value Adjustment (2)					11.6		—
Less Fair Value Adjustment - Current Portion (2)					(2.4)		—
Less Amounts due in One Year					(1,090.5)		(750.3)
Unamortized Premiums and Discounts, Net					37.8		41.7
Unamortized Debt Issuance Costs					(64.5)		(76.1)
Total Other Long-Term Debt					$	14,085.4	$	14,016.4
Total Eversource Long-Term Debt					$	26,872.4	$	25,701.6

(1)     As a result of the CL&P long-term debt issuance in January 2025, $397.1 million of current portion of long-term debt was reclassified to Long-Term Debt on Eversource’s and CL&P’s balance sheets as of December 31, 2024.

(2)    The fair value adjustment amount is the purchase price adjustments, net of amortization, required to record Aquarion’s long-term debt at fair value upon the 2017 acquisition date. As of December 31, 2024, this fair value adjustment was reclassified to Liabilities Held for Sale. As of December 31, 2025, the fair value adjustment was reclassified to Long-Term Debt. For further information, see Note 24, “Assets Held for Sale.”