Revenues Revenues (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue [Table Text Block]

NSP-Wisconsin’s operating revenues consisted of the following:

	Year Ended Dec. 31, 2019
(Millions of Dollars)	Electric		Natural Gas		All Other		Total
Major revenue types
Revenue from contracts with customers:
Residential	$	240.2	$	73.0	$	—	$	313.2
C&I	408.7		57.4		—		466.1
Other	5.6		—		0.4		6.0
Total retail	654.5		130.4		0.4		785.3
Interchange	176.6		—		—		176.6
Other	1.1		3.6		—		4.7
Total revenue from contracts with customers	832.2		134.0		0.4		966.6
Alternative revenue and other	11.9		2.4		—		14.3
Total revenues	$	844.1	$	136.4	$	0.4	$	980.9

	Year Ended Dec. 31, 2018
(Millions of Dollars)	Electric		Natural Gas		All Other		Total
Major revenue types
Revenue from contracts with customers:
Residential	$	255.2	$	73.0	$	0.1	$	328.3
C&I	444.3		61.6		0.1		506.0
Other	6.1		—		1.1		7.2
Total retail	705.6		134.6		1.3		841.5
Interchange	157.9		—		—		157.9
Other	3.6		4.6		—		8.2
Total revenue from contracts with customers	867.1		139.2		1.3		1,007.6
Alternative revenue and other	11.5		2.4		—		13.9
Total revenues	$	878.6	$	141.6	$	1.3	$	1,021.5