ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2023

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,
	2023								2022
(Millions of Dollars)	Eversource		CL&P		NSTAR Electric		PSNH		Eversource		CL&P		NSTAR Electric		PSNH
Balance as of Beginning of Year	$	502.7	$	37.4	$	101.3	$	4.9	$	500.1	$	35.0	$	97.5	$	4.7
Liabilities Settled During the Year	(24.9)		—		—		—		(22.3)		—		—		—
Accretion	29.2		2.5		4.3		0.3		28.9		2.4		4.1		0.2
Revisions in Estimated Cash Flows	(1.2)		—		(0.8)		—		(4.0)		—		(0.3)		—
Balance as of End of Year	$	505.8	$	39.9	$	104.8	$	5.2	$	502.7	$	37.4	$	101.3	$	4.9