ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2022

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,
	2022								2021
(Millions of Dollars)	Eversource		CL&P		NSTAR Electric		PSNH		Eversource		CL&P		NSTAR Electric		PSNH
Balance as of Beginning of Year	$	500.1	$	35.0	$	97.5	$	4.7	$	499.7	$	33.4	$	91.8	$	4.4
Liabilities Settled During the Year	(22.3)		—		—		—		(23.9)		(0.6)		—		—
Accretion	28.9		2.4		4.1		0.2		29.4		2.2		4.0		0.3
Revisions in Estimated Cash Flows	(4.0)		—		(0.3)		—		(5.1)		—		1.7		—
Balance as of End of Year	$	502.7	$	37.4	$	101.3	$	4.9	$	500.1	$	35.0	$	97.5	$	4.7