Property Plant and Equipment Property Plant and Equipment

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment Disclosure

(Millions of Dollars)	Dec. 31, 2018			Dec. 31, 2017
Property, plant and equipment
Electric plant	$	13,604.5		$	12,627.6
Natural gas plant	4,387.6			4,102.1
Common and other property	1,023.7			1,022.3
Plant to be retired (a)	321.9			11.0
CWIP	573.3			1,014.3
Total property, plant and equipment	19,911.0			18,777.3
Less accumulated depreciation	(4,791.0		)	(4,751.5		)
	$	15,120.0		$	14,025.8

^(a)  In 2018, the CPUC approved early retirement of PSCo’s Comanche Units 1 and 2 in approximately 2022 and 2025, respectively. PSCo also expects Craig Unit 1 to be retired early in 2025. Amounts are presented net of accumulated depreciation.

Joint Ownership of Generation, Transmission and Gas Facilities

Jointly owned assets as of Dec. 31, 2018:

(Millions of Dollars)	Plant in Service		Accumulated Depreciation		CWIP		Percent Owned
Electric Generation:
Hayden Unit 1	$	152.8	$	76.5	$	—	76	%
Hayden Unit 2	148.9		68.0		—		37
Hayden Common Facilities	40.8		20.9		—		53
Craig Units 1 and 2	81.0		40.0		—		10
Craig Common Facilities	39.1		20.9		—		7
Comanche Unit 3	886.3		130.7		—		67
Comanche Common Facilities	27.9		2.5		0.1		82
Electric Transmission:
Transmission and other facilities	182.8		63.2		0.7		Various
Gas Transportation:
Rifle, CO to Avon, CO	21.5		7.2		0.1		60
Gas Tran Compressor	8.4		0.9		—		50
Total	$	1,589.5	$	430.8	$	0.9

PSCo’s share of operating expenses and construction expenditures are included in the applicable utility accounts. Respective owners are responsible for providing their own financing.