Revenues

3 Months Ended

Mar. 31, 2021

Revenue from Contract with Customer [Abstract]

Revenue

Revenue is classified by the type of goods/services rendered and market/customer type. SPS’ operating revenues consisted of the following:

	Three Months Ended March 31
(Millions of Dollars)	2021		2020
Major revenue types
Revenue from contracts with customers:
Residential	$	91	$	73
C&I	189		169
Other	9		8
Total retail	289		250
Wholesale	558		73
Transmission	71		63
Other	2		—
Total revenue from contracts with customers	920		386
Alternative revenue and other	14		9
Total revenues	$	934	$	395