Revenues (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

SPS’ operating revenues consisted of the following:

	Year Ended Dec. 31
(Millions of Dollars)	2020		2019		2018
Major revenue types
Revenue from contracts with customers:
Residential	$	359	$	352	$	364
C&I	739		800		828
Other	39		41		45
Total retail	1,137		1,193		1,237
Wholesale	345		361		426
Transmission	279		240		231
Other	4		3		13
Total revenue from contracts with customers	1,765		1,797		1,907
Alternative revenue and other	105		29		26
Total revenues	$	1,870	$	1,826	$	1,933