Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

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, 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
	Twelve Months Ended December 31, 2020
Electric and Gas Operating Revenues (millions):	Electric		Gas		Total
Billed and Unbilled Revenue:
Residential	$	128.7	$	73.1	$	201.8
Commercial & Industrial		91.4		104.5		195.9
Other		6.6		7.6		14.2
Total Billed and Unbilled Revenue		226.7		185.2		411.9
Rate Adjustment Mechanism Revenue		0.5		6.2		6.7
Total Electric and Gas Operating Revenues	$	227.2	$	191.4	$	418.6

	Twelve Months Ended December 31, 2019
Electric and Gas Operating Revenues (millions):	Electric		Gas			Total
Billed and Unbilled Revenue:
Residential	$	121.5	$	81.4		$	202.9
Commercial & Industrial		93.8		120.1			213.9
Other		7.8		10.6			18.4
Total Billed and Unbilled Revenue		223.1		212.1			435.2
Rate Adjustment Mechanism Revenue		10.8		(8.7	)		2.1
Total Electric and Gas Operating Revenues	$	233.9	$	203.4		$	437.3

Components of Accrued Revenue

The following table shows the components of Accrued Revenue as of December 31, 2021 and 2020.

Accrued Revenue (millions)	December 31,
	2021		2020
Regulatory Assets—Current	$	47.4	$	37.3
Unbilled Revenues		13.8		13.6
Total Accrued Revenue	$	61.2	$	50.9

Components of Exchange Gas Receivable

The following table shows the components of Exchange Gas Receivable as of December 31, 2021 and 2020.

Exchange Gas Receivable (millions)	December 31,
	2021		2020
Northern Utilities	$	6.7	$	4.4
Fitchburg		0.7		0.5
Total Exchange Gas Receivable	$	7.4	$	4.9

Components of Gas Inventory

The following table shows the components of Gas Inventory as of December 31, 2021 and 2020.

Gas Inventory (millions)	December 31,
	2021		2020
Natural Gas	$	0.5	$	0.2
Propane		0.4		0.3
Liquefied Natural Gas & Other		0.1		0.1
Total Gas Inventory	$	1.0	$	0.6

Regulatory Assets

Regulatory Assets consist of the following (millions)	December 31,
	2021		2020
Retirement Benefits	$	86.4	$	103.7
Energy Supply & Other Rate Adjustment Mechanisms		44.1		34.1
Deferred Storm Charges		3.3		4.1
Environmental		4.6		5.2
Income Taxes		2.6		3.4
Other Deferred Charges		15.3		14.2
Total Regulatory Assets		156.3		164.7
Less: Current Portion of Regulatory Assets(1)		47.4		37.3
Regulatory Assets—noncurrent	$	108.9	$	127.4

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

Regulatory Liabilities

Regulatory Liabilities consist of the following (millions)	December 31,
	2021		2020
Rate Adjustment Mechanisms	$	7.7	$	4.1
Income Taxes		44.3		45.5
Other		0.1		0.2
Total Regulatory Liabilities		52.1		49.8
Less: Current Portion of Regulatory Liabilities		9.5		5.5
Regulatory Liabilities—noncurrent	$	42.6	$	44.3

Fair Value of Marketable Securities

Fair Value of Marketable Securities (millions)	December 31,
	2021		2020
Money Market Funds	$	5.7	$	5.7
Total Marketable Securities	$	5.7	$	5.7

Components of Energy Supply Obligations

	December 31,
Energy Supply Obligations consist of the following: (millions)	2021		2020
Renewable Energy Portfolio Standards	$	7.8	$	5.7
Exchange Gas Obligation		6.7		4.4
Power Supply Contract Divestitures		—		0.3
Total Energy Supply Obligations	$	14.5	$	10.4

Deferred Compensation Plan [Member]

Components of Energy Supply Obligations

Fair Value of Marketable Securities (millions)	December 31,
	2021		2020
Equity Funds	$	0.2	$	0.2
Money Market Funds		0.4		0.3
Total Marketable Securities	$	0.6	$	0.5