COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Schedule of Environmental Loss Contingencies by Site

A reconciliation of the activity in the environmental reserves is as follows:

(Millions of Dollars)	Eversource		CL&P		NSTAR Electric		PSNH
Balance as of January 1, 2019	$	64.7	$	5.4	$	10.9	$	5.4
Additions	26.5		7.0		0.5		2.8
Payments/Reductions	(10.2)		(1.0)		(3.4)		(0.7)
Balance as of December 31, 2019	81.0		11.4		8.0		7.5
Increase Due to CMA Asset Acquisition	22.9		—		—		—
Additions	8.4		4.2		0.7		—
Payments/Reductions	(9.9)		(3.3)		(4.0)		(0.4)
Balance as of December 31, 2020	$	102.4	$	12.3	$	4.7	$	7.1

The number of environmental sites for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows:

	Eversource	CL&P	NSTAR Electric	PSNH
2020	63	15	12	9
2019	57	15	15	9

Schedule of Estimated Future Annual Costs of Long term Contractual Agreement

The estimated future annual costs of significant executed, non-cancelable, long-term contractual arrangements in effect as of December 31, 2020 are as follows:

Eversource
(Millions of Dollars)	2021		2022		2023		2024		2025		Thereafter		Total
Renewable Energy	$	650.0	$	716.8	$	652.3	$	648.8	$	651.5	$	3,490.7	$	6,810.1
Natural Gas Procurement	558.9		374.1		292.0		263.1		260.2		1,825.8		3,574.1
Purchased Power and Capacity	69.4		75.5		86.8		79.6		60.3		13.2		384.8
Peaker CfDs	30.0		34.2		46.9		41.6		31.3		102.4		286.4
Transmission Support Commitments	20.5		18.0		18.1		19.2		19.7		19.7		115.2
Total	$	1,328.8	$	1,218.6	$	1,096.1	$	1,052.3	$	1,023.0	$	5,451.8	$	11,170.6

CL&P
(Millions of Dollars)	2021		2022		2023		2024		2025		Thereafter		Total
Renewable Energy	$	484.4	$	548.3	$	547.2	$	549.1	$	551.2	$	2,645.5	$	5,325.7
Purchased Power and Capacity	65.8		71.9		83.3		76.6		57.4		0.1		355.1
Peaker CfDs	30.0		34.2		46.9		41.6		31.3		102.4		286.4
Transmission Support Commitments	8.1		7.1		7.2		7.6		7.8		7.8		45.6
Total	$	588.3	$	661.5	$	684.6	$	674.9	$	647.7	$	2,755.8	$	6,012.8

NSTAR Electric
(Millions of Dollars)	2021		2022		2023		2024		2025		Thereafter		Total
Renewable Energy	$	98.0	$	100.0	$	75.4	$	72.9	$	73.1	$	522.1	$	941.5
Purchased Power and Capacity	3.1		3.1		3.0		3.0		2.9		13.1		28.2
Transmission Support Commitments	8.1		7.1		7.1		7.5		7.7		7.7		45.2
Total	$	109.2	$	110.2	$	85.5	$	83.4	$	83.7	$	542.9	$	1,014.9

PSNH
(Millions of Dollars)	2021		2022		2023		2024		2025		Thereafter		Total
Renewable Energy	$	67.6	$	68.5	$	29.7	$	26.8	$	27.2	$	323.1	$	542.9
Purchased Power and Capacity	0.5		0.5		0.5		—		—		—		1.5
Transmission Support Commitments	4.3		3.8		3.8		4.1		4.2		4.2		24.4
Total	$	72.4	$	72.8	$	34.0	$	30.9	$	31.4	$	327.3	$	568.8

The total costs incurred under these agreements were as follows:

Eversource	For the Years Ended December 31,
(Millions of Dollars)	2020		2019		2018
Renewable Energy	$	584.2	$	320.8	$	218.5
Natural Gas Procurement	453.4		448.5		432.4
Purchased Power and Capacity	62.7		62.1		72.0
Peaker CfDs	22.7		13.0		20.9
Transmission Support Commitments	22.1		21.8		23.4

	For the Years Ended December 31,
	2020						2019						2018
(Millions of Dollars)	CL&P		NSTAR Electric		PSNH		CL&P		NSTAR Electric		PSNH		CL&P		NSTAR Electric		PSNH
Renewable Energy	$	426.3	$	88.8	$	69.1	$	160.6	$	89.9	$	70.3	$	63.2	$	89.8	$	65.5
Purchased Power and Capacity	59.3		3.1		0.3		50.4		5.1		6.6		49.4		4.4		18.2
Peaker CfDs	22.7		—		—		13.0		—		—		20.9		—		—
Transmission Support Commitments	8.7		8.7		4.7		8.6		8.6		4.6		9.2		9.2		5.0

Schedule of Guarantor Obligations

The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries and affiliates to external parties as of December 31, 2020:

Company (Obligor)	Description	Maximum Exposure (in millions)		Expiration Dates
North East Offshore LLC	Construction-related purchase agreements with third-party contractors (1)	$	30.5	(1)
Eversource Investment LLC	Funding and indemnification obligations of North East Offshore LLC (2)	—		(2)
Sunrise Wind LLC	OREC capacity production (3)	2.2		(3)
South Fork Wind, LLC	Transmission interconnection	1.7		—
Bay State Wind LLC	Real estate purchase	2.5		2021
Various	Surety bonds (4)	56.6		2021 - 2023
Rocky River Realty Company and Eversource Service	Lease payments for real estate	5.2		2024

(1)    Eversource parent issued guarantees on behalf of its 50 percent-owned affiliate, North East Offshore LLC (NEO), under which Eversource parent agreed to guarantee 50 percent of NEO’s performance of obligations under certain purchase agreements with third-party contactors, in an amount not to exceed $1.3 billion with an expiration date in 2025. Eversource parent also issued a separate guarantee to Ørsted on behalf of NEO, under which Eversource parent agreed to guarantee 50 percent of NEO’s payment obligations under certain offshore wind project construction-related agreements with Ørsted in an aggregate amount not to exceed $62.5 million. Any amounts paid under this guarantee to Ørsted will count toward, but not increase, the maximum amount of the Funding Guarantee described in Note 2, below. The guarantee expires upon the full performance of the guaranteed obligations.    

(2)    Eversource parent issued a guarantee (Funding Guarantee) on behalf of Eversource Investment LLC (EI), its wholly-owned subsidiary that holds a 50 percent ownership interest in NEO, under which Eversource parent agreed to guarantee certain funding obligations and certain indemnification payments of EI under the Amended and Restated Limited Liability Company Operating Agreement of NEO, in an amount not to exceed $910 million. The guaranteed obligations include payment of EI's funding obligations during the construction phase of NEO’s underlying offshore wind projects and indemnification obligations associated with third party credit support for its investment in NEO. Eversource parent’s obligations under the Funding Guarantee expire upon the full performance of the guaranteed obligations.

(3)    On October 25, 2019, Eversource parent issued a guarantee on behalf of its 50 percent-owned affiliate, Sunrise Wind LLC, whereby Eversource parent will guarantee Sunrise Wind LLC's performance of certain obligations, in an amount not to exceed $15.4 million, under the Offshore Wind Renewable Energy Certificate Purchase and Sale Agreement (the Agreement). The Agreement was executed on October 23, 2019, by and between the New York State Energy Research and Development Authority (NYSERDA) and Sunrise Wind LLC. The guarantee expires upon the full performance of the guaranteed obligations.    

(4)    Surety bond expiration dates reflect termination dates, the majority of which will be renewed or extended.  Certain surety bonds contain credit ratings triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource parent are downgraded.