Revenue from Contracts with Customers

9 Months Ended

Sep. 30, 2020

Revenue from Contract with Customer [Abstract]

Revenue from Contract with Customer [Text Block]

Revenue from Contracts with Customers

Nature of Goods and Services

We provide retail electric and natural gas services to three primary customer classes. Our residential customers include single private dwellings and individual apartments. Our commercial customers consist primarily of main street businesses, and our industrial customers consist primarily of manufacturing and processing businesses that turn raw materials into products.

Electric Segment - Our regulated electric utility business primarily provides generation, transmission, and distribution services to customers in our Montana and South Dakota jurisdictions. We recognize revenue when electricity is delivered to the customer. Payments on our tariff based sales are generally due 20-30 days after the billing date.

Natural Gas Segment - Our regulated natural gas utility business primarily provides production, storage, transmission, and distribution services to customers in our Montana, South Dakota, and Nebraska jurisdictions. We recognize revenue when natural gas is delivered to the customer. Payments on our tariff based sales are generally due 20-30 days after the billing date.

Disaggregation of Revenue

The following tables disaggregate our revenue by major source and customer class (in millions):

	Three Months Ended
	September 30, 2020						September 30, 2019
	Electric		Natural Gas		Total		Electric		Natural Gas		Total
Montana	$	78.5	$	9.9	$	88.4	$	68.4	$	8.9	$	77.3
South Dakota	18.9		1.7		20.6		16.0		1.7		17.7
Nebraska	—		1.7		1.7		—		1.8		1.8
Residential	97.4		13.3		110.7		84.4		12.4		96.8
Montana	89.1		5.6		94.7		87.7		5.5		93.2
South Dakota	27.4		1.0		28.4		26.3		1.3		27.6
Nebraska	—		0.7		0.7		—		0.9		0.9
Commercial	116.5		7.3		123.8		114.0		7.7		121.7
Industrial	9.2		0.1		9.3		10.6		0.1		10.7
Lighting, Governmental, Irrigation, and Interdepartmental	11.9		0.1		12.0		12.4		0.1		12.5
Total Customer Revenues	235.0		20.8		255.8		221.4		20.3		241.7
Other Tariff and Contract Based Revenues	14.9		8.3		23.2		15.3		7.7		23.0
Total Revenue from Contracts with Customers	249.9		29.1		279.0		236.7		28.0		264.7
Regulatory amortization	(5.7)		7.4		1.7		4.5		5.6		10.1
Total Revenues	$	244.2	$	36.5	$	280.7	$	241.2	$	33.6	$	274.8

	Nine Months Ended
	September 30, 2020						September 30, 2019
	Electric		Natural Gas		Total		Electric		Natural Gas		Total
Montana	$	237.7	$	65.7	$	303.4	$	225.4	$	73.3	$	298.7
South Dakota	52.4		16.7		69.1		47.4		20.4		67.8
Nebraska	—		12.9		12.9		—		15.7		15.7
Residential	290.1		95.3		385.4		272.8		109.4		382.2
Montana	252.5		33.0		285.5		257.3		38.0		295.3
South Dakota	77.1		11.2		88.3		71.2		14.1		85.3
Nebraska	—		6.2		6.2		—		8.3		8.3
Commercial	329.6		50.4		380.0		328.5		60.4		388.9
Industrial	27.2		0.5		27.7		32.4		0.7		33.1
Lighting, Governmental, Irrigation, and Interdepartmental	26.4		0.7		27.1		25.2		0.6		25.8
Total Customer Revenues	673.3		146.9		820.2		658.9		171.1		830.0
Other Tariff and Contract Based Revenues	44.1		26.5		70.6		46.5		26.6		73.1
Total Revenue from Contracts with Customers	717.4		173.4		890.8		705.4		197.7		903.1
Regulatory amortization	(10.7)		5.1		(5.6)		28.5		(1.9)		26.6
Total Revenues	$	706.7	$	178.5	$	885.2	$	733.9	$	195.8	$	929.7