PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSION (Tables)

3 Months Ended

Mar. 31, 2026

Postemployment Benefits [Abstract]

Schedule of Components of Net Periodic Benefit Expense/(Income)

	Pension and SERP								PBOP
	For the Three Months Ended March 31, 2026								For the Three Months Ended March 31, 2026
(Millions of Dollars)	Eversource		CL&P		NSTAR Electric		PSNH		Eversource		CL&P		NSTAR Electric		PSNH
Service Cost	$	18.4	$	3.9	$	3.2	$	1.6	$	1.6	$	0.3	$	0.3	$	0.1
Interest Cost	59.1		12.1		12.2		6.2		7.2		1.3		1.9		0.8
Expected Return on Plan Assets	(117.3)		(23.9)		(28.9)		(12.4)		(22.7)		(2.6)		(11.6)		(1.5)
Actuarial Loss/(Gain)	8.7		1.1		2.8		0.4		(0.4)		—		—		—
Prior Service Cost/(Credit)	0.2		—		0.1		—		(5.4)		0.3		(4.2)		0.1
Total Net Periodic Benefit Plan Income	$	(30.9)	$	(6.8)	$	(10.6)	$	(4.2)	$	(19.7)	$	(0.7)	$	(13.6)	$	(0.5)
Intercompany Income Allocations	N/A		$	(1.8)	$	(1.5)	$	(0.5)	N/A		$	(0.6)	$	(0.8)	$	(0.3)
	Pension and SERP								PBOP
	For the Three Months Ended March 31, 2025								For the Three Months Ended March 31, 2025
(Millions of Dollars)	Eversource		CL&P		NSTAR Electric		PSNH		Eversource		CL&P		NSTAR Electric		PSNH
Service Cost	$	16.4	$	3.8	$	2.5	$	1.6	$	1.6	$	0.2	$	0.2	$	0.1
Interest Cost	63.2		12.8		13.0		6.8		8.0		1.4		2.2		0.8
Expected Return on Plan Assets	(113.3)		(22.9)		(27.7)		(11.9)		(21.2)		(2.4)		(10.5)		(1.4)
Actuarial Loss/(Gain)	10.0		1.2		3.2		0.5		(0.3)		—		—		—
Prior Service Cost/(Credit)	0.3		—		0.1		—		(5.4)		0.3		(4.2)		0.1
Settlement Loss	3.3		—		—		—		—		—		—		—
Total Net Periodic Benefit Plan Income	$	(20.1)	$	(5.1)	$	(8.9)	$	(3.0)	$	(17.3)	$	(0.5)	$	(12.3)	$	(0.4)
Intercompany Expense/(Income) Allocations	N/A		$	0.1	$	0.3	$	0.1	N/A		$	(0.5)	$	(0.7)	$	(0.2)