Property Plant and Equipment Property Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Public Utility Property, Plant, and Equipment

Major classes of property, plant and equipment

(Millions of Dollars)	Dec. 31, 2021		Dec. 31, 2020
Property, plant and equipment, net
Electric plant	$	16,543	$	15,736
Natural gas plant	5,471		5,037
Common and other property	1,224		1,191
Plant to be retired (a)	182		225
CWIP	681		510
Total property, plant and equipment	24,101		22,699
Less accumulated depreciation	(5,657)		(5,229)
Property, plant and equipment, net	$	18,444	$	17,470

(a)Includes regulator-approved retirements of Comanche Units 1 and 2 and jointly owned Craig Unit 1. Also includes PSCo’s planned retirement of jointly owned Craig Unit 2.

Schedule of Jointly Owned Utility Plants

Joint Ownership of Generation, Transmission and Gas Facilities

Jointly owned assets as of Dec. 31, 2021:

(Millions of Dollars, Except Percent Owned)	Plant in Service		Accumulated Depreciation		Percent Owned
Electric generation:
Hayden Unit 1	$	156	$	99	76	%
Hayden Unit 2	151		78		37
Hayden common facilities	42		27		53
Craig Units 1 and 2	81		48		10
Craig common facilities	39		25		7
Comanche Unit 3	917		154		67
Comanche common facilities	28		2		82
Electric transmission:
Transmission and other facilities	182		63		Various
Gas transmission:
Rifle, CO to Avon, CO	22		8		60
Gas transmission compressor	8		2		50
Total (a)	$	1,626	$	506