FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping

Carrying amounts and estimated fair values are as follows:

	As of September 30, 2017				As of December 31, 2016
Eversource (Millions of Dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Preferred Stock Not Subject to Mandatory Redemption	$	155.6	$	160.3	$	155.6	$	158.3
Long-Term Debt	11,425.9		11,968.1		9,603.2		9,980.5

	CL&P				NSTAR Electric				PSNH				WMECO
(Millions of Dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value		Carrying Amount		Fair Value		Carrying Amount		Fair Value
As of September 30, 2017:
Preferred Stock Not Subject to Mandatory Redemption	$	116.2	$	115.9	$	43.0	$	44.4	$	—	$	—	$	—	$	—
Long-Term Debt	3,058.9		3,388.8		2,426.2		2,598.1		1,002.6		1,047.0		566.2		603.7
As of December 31, 2016:
Preferred Stock Not Subject to Mandatory Redemption	$	116.2	$	114.7	$	43.0	$	43.6	$	—	$	—	$	—	$	—
Long-Term Debt	2,766.0		3,049.6		2,078.1		2,201.6		1,072.0		1,109.7		566.5		589.0