Revenues (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

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

	Three Months Ended
(Thousands of Dollars)	Sept. 30, 2018		Sept. 30, 2017
Major product lines
Revenue from contracts with customers:
Residential	$	114,387	$	113,380
Commercial and industrial (C&I)	229,457		241,295
Other	12,983		13,399
Total retail	356,827		368,074
Wholesale	117,949		116,635
Transmission	60,726		56,143
Other	1,792		3,862
Total revenue from contracts with customers	537,294		544,714
Alternative revenue and other	2,769		6,909
Total revenues	$	540,063	$	551,623

	Nine Months Ended
(Thousands of Dollars)	Sept. 30, 2018		Sept. 30, 2017
Major product lines
Revenue from contracts with customers:
Residential	$	279,543	$	277,169
C&I	625,988		658,057
Other	34,010		35,253
Total retail	939,541		970,479
Wholesale	326,810		309,669
Transmission	175,342		166,715
Other	12,181		7,872
Total revenue from contracts with customers	1,453,874		1,454,735
Alternative revenue and other	14,759		36,756
Total revenues	$	1,468,633	$	1,491,491