Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Components of Gas and Electric Operating Revenue

In the following tables, revenue is classified by the types of goods/services rendered and market/customer type.

	Twelve Months Ended
	December 31, 2023
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	181.6		$	98.8		$	280.4
Commercial & Industrial		120.1			146.9			267.0
Other		10.0			8.1			18.1
Total Billed and Unbilled Revenue		311.7			253.8			565.5
Rate Adjustment Mechanism Revenue		(5.2	)		(3.2	)		(8.4	)
Total Electric and Gas Operating Revenues	$	306.5		$	250.6		$	557.1

	Twelve Months Ended
	December 31, 2022
Electric and Gas Operating Revenues (millions):	Electric		Gas		Total
Billed and Unbilled Revenue:
Residential	$	159.9	$	98.2	$	258.1
Commercial & Industrial		112.6		153.8		266.4
Other		17.7		11.3		29.0
Total Billed and Unbilled Revenue		290.2		263.3		553.5
Rate Adjustment Mechanism Revenue		7.7		2.0		9.7
Total Electric and Gas Operating Revenues	$	297.9	$	265.3	$	563.2

	Twelve Months Ended
	December 31, 2021
Electric and Gas Operating Revenues (millions):	Electric		Gas		Total
Billed and Unbilled Revenue:
Residential	$	135.1	$	83.9	$	219.0
Commercial & Industrial		103.3		124.1		227.4
Other		10.1		9.6		19.7
Total Billed and Unbilled Revenue		248.5		217.6		466.1
Rate Adjustment Mechanism Revenue		—		7.2		7.2
Total Electric and Gas Operating Revenues	$	248.5	$	224.8	$	473.3

Estimated Percentage of Decoupled Sales

Revenue Decoupling

Estimated Percentage of Decoupled Sales

For Periods Presented

Electric
Before June 1, 2022	27%
After June 1, 2022	Substantially All
Gas
Before August 1, 2022	11%
After August 1, 2022	42%

Components of Accrued Revenue

The following table shows the components of Accrued Revenue as of December 31, 2023 and 2022.

	December 31,
Accrued Revenue (millions)	2023		2022
Regulatory Assets—Current	$	56.5	$	66.5
Unbilled Revenues		6.9		6.3
Total Accrued Revenue	$	63.4	$	72.8

Components of Exchange Gas Receivable

The following table shows the components of Exchange Gas Receivable as of December 31, 2023 and 2022.

	December 31,
Exchange Gas Receivable (millions)	2023		2022
Northern Utilities	$	8.6	$	16.3
Fitchburg		0.8		1.7
Total Exchange Gas Receivable	$	9.4	$	18.0

Components of Gas Inventory

The following table shows the components of Gas Inventory as of December 31, 2023 and 2022.

	December 31,
Gas Inventory (millions)	2023		2022
Natural Gas	$	0.3	$	1.0
Propane		0.3		0.4
Liquefied Natural Gas & Other		0.4		0.4
Total Gas Inventory	$	1.0	$	1.8

Regulatory Assets

The Company currently receives recovery in rates or expects to receive recovery of these hardship accounts in future rate cases.

	December 31,
Regulatory Assets consist of the following (millions)	2023		2022
Retirement Benefits	$	29.8	$	29.1
Energy Supply & Other Rate Adjustment Mechanisms		52.4		63.0
Deferred Storm Charges		9.2		3.4
Environmental		6.1		5.9
Income Taxes		1.1		1.8
Other Deferred Charges		11.0		11.1
Total Regulatory Assets		109.6		114.3
Less: Current Portion of Regulatory Assets(1)		56.5		66.5
Regulatory Assets—noncurrent	$	53.1	$	47.8

(1)Reflects amounts included in Accrued Revenue on the Company’s Consolidated Balance Sheets.

Regulatory Liabilities

	December 31,
Regulatory Liabilities consist of the following (millions)	2023		2022
Rate Adjustment Mechanisms	$	9.3	$	10.9
Income Taxes		38.6		41.0
Total Regulatory Liabilities		47.9		51.9
Less: Current Portion of Regulatory Liabilities		13.5		15.0
Regulatory Liabilities—noncurrent	$	34.4	$	36.9

Fair Value of Marketable Securities

Changes in the fair value of these investments are recorded in Other (Income) Expense, Net.

	December 31,
Fair Value of Marketable Securities (millions)	2023		2022
Money Market Funds	$	2.0	$	5.8
Fixed Income Funds		4.0		—
Total Marketable Securities	$	6.0	$	5.8

Components of Energy Supply Obligations

The following discussion and table summarize the nature and amounts of the items recorded as Energy Supply Obligations on the Company’s Consolidated Balance Sheets.

	December 31,
Energy Supply Obligations consist of the following (millions)	2023		2022
Renewable Energy Portfolio Standards	$	6.4	$	7.8
Exchange Gas Obligation		8.6		16.3
Total Energy Supply Obligations	$	15.0	$	24.1

Deferred Compensation Plan [Member]

Fair Value of Marketable Securities

Changes in the fair value of these investments are recorded in Other (Income) Expense, Net.

	December 31,
Fair Value of Marketable Securities (millions)	2023		2022
Equity Funds	$	1.1	$	0.5
Fixed Income Funds		0.1		—
Money Market Funds		0.1		0.1
Total Marketable Securities	$	1.3	$	0.6