Revenue Recognition (Tables)

9 Months Ended

Sep. 30, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The tables below reconcile revenue disaggregation by customer class to segment revenue, as well as to revenues reflected on the Condensed Statements of Consolidated Income (Loss) (unaudited) for the three and nine months ended September 30, 2020 and September 30, 2019:

Three Months Ended September 30, 2020 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Customer Revenues(1)
Residential	$	306.9	$	164.8	$	—	$	471.7
Commercial	91.8		132.3		—		224.1
Industrial	42.8		102.7		—		145.5
Off-system	6.0		—		—		6.0
Miscellaneous	6.8		7.2		0.2		14.2
Total Customer Revenues	$	454.3	$	407.0	$	0.2	$	861.5
Other Revenues(2)	15.8		25.2		—		41.0
Total Operating Revenues	$	470.1	$	432.2	$	0.2	$	902.5

(1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues.

(2) Other revenues represent revenue earned under alternative revenue programs.

Three Months Ended September 30, 2019 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Customer Revenues(1)
Residential	$	288.3	$	148.7	$	—	$	437.0
Commercial	90.9		136.3		—		227.2
Industrial	45.3		151.5		—		196.8
Off-system	16.9		—		—		16.9
Miscellaneous	9.8		3.1		0.2		13.1
Total Customer Revenues	$	451.2	$	439.6	$	0.2	$	891.0
Other Revenues(2)	12.4		28.1		—		40.5
Total Operating Revenues	$	463.6	$	467.7	$	0.2	$	931.5
(1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs.
Nine Months Ended September 30, 2020 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Customer Revenues(1)
Residential	$	1,518.1	$	411.5	$	—	$	1,929.6
Commercial	483.9		365.4		—		849.3
Industrial	165.6		301.1		—		466.7
Off-system	32.7		—		—		32.7
Miscellaneous	24.6		16.6		0.6		41.8
Total Customer Revenues	$	2,224.9	$	1,094.6	$	0.6	$	3,320.1
Other Revenues(2)	79.5		71.1		—		150.6
Total Operating Revenues	$	2,304.4	$	1,165.7	$	0.6	$	3,470.7
(1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs.
Nine Months Ended September 30, 2019 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Customer Revenues(1)
Residential	$	1,638.6	$	373.4	$	—	$	2,012.0
Commercial	543.2		370.7		—		913.9
Industrial	181.1		470.6		—		651.7
Off-system	60.4		—		—		60.4
Miscellaneous	39.4		16.7		0.6		56.7
Total Customer Revenues	$	2,462.7	$	1,231.4	$	0.6	$	3,694.7
Other Revenues(2)	43.5		73.5		—		117.0
Total Operating Revenues	$	2,506.2	$	1,304.9	$	0.6	$	3,811.7
(1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs.

Customer Accounts Receivable

The opening and closing balances of customer receivables for the nine months ended September 30, 2020 are presented in the table below. We had no significant contract assets or liabilities during the period. Additionally, we have not incurred any significant costs to obtain or fulfill contracts.

(in millions)	Customer Accounts Receivable, Billed (less reserve)		Customer Accounts Receivable, Unbilled (less reserve)
Balance as of December 31, 2019	$	466.6	$	346.6
Balance as of September 30, 2020	291.0		178.8
Decrease	$	(175.6)	$	(167.8)

Financing Receivable, Allowance for Credit Loss

A rollforward of our allowance for credit losses for the three and nine months ended September 30, 2020 are presented in the tables below:

Three Months Ended September 30, 2020 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Beginning balance	$	25.4	$	5.2	$	0.8	$	31.4
Current period provisions	8.2		2.3		—		10.5
Write-offs charged against allowance	(4.3)		(0.5)		—		(4.8)
Recoveries of amounts previously written off	2.2		—		—		2.2
Ending balance of the allowance for credit losses	$	31.5	$	7.0	$	0.8	$	39.3
Nine Months Ended September 30, 2020 (in millions)	Gas Distribution Operations		Electric Operations		Corporate and Other		Total
Beginning balance(1)	9.1		3.1		0.8		13.0
Current period provisions	30.6		6.7		—		37.3
Write-offs charged against allowance	(18.1)		(3.0)		—		(21.1)
Recoveries of amounts previously written off	9.9		0.2		—		10.1
Ending balance of the allowance for credit losses	31.5		7.0		0.8		39.3
(1)Total beginning balance differs from that presented in the Condensed Statements of Consolidated Balance Sheet (unaudited) as it excludes Columbia of Massachusetts. Columbia of Massachusetts' customer receivables and related allowance for credit losses are classified as held for sale at September 30, 2020.