Selected Balance Sheet Data (Tables)

6 Months Ended

Jun. 30, 2014

Balance Sheet Related Disclosures [Abstract]

Accounts Receivable, Net

(Thousands of Dollars)	June 30, 2014			Dec. 31, 2013
Accounts receivable, net
Accounts receivable	$	793,537		$	797,267
Less allowance for bad debts	(50,807		)	(53,107		)
	$	742,730		$	744,160

Inventories

(Thousands of Dollars)	June 30, 2014		Dec. 31, 2013
Inventories
Materials and supplies	$	234,212	$	225,308
Fuel	168,314		189,485
Natural gas	98,744		161,745
	$	501,270	$	576,538

Property, Plant and Equipment, Net

(Thousands of Dollars)	June 30, 2014			Dec. 31, 2013
Property, plant and equipment, net
Electric plant	$	31,360,194		$	30,341,310
Natural gas plant	4,211,851			4,086,651
Common and other property	1,467,336			1,485,547
Plant to be retired (a)	85,808			101,279
Construction work in progress	2,502,721			2,371,566
Total property, plant and equipment	39,627,910			38,386,353
Less accumulated depreciation	(12,854,913		)	(12,608,305		)
Nuclear fuel	2,200,534			2,186,799
Less accumulated amortization	(1,903,154		)	(1,842,688		)
	$	27,070,377		$	26,122,159

^(a)  As a result of the 2010 Colorado Public Utilities Commission (CPUC) approval of PSCo’s Clean Air Clean Jobs Act (CACJA) compliance plan and the December 2013 approval of PSCo’s preferred plans for applicable generating resources, PSCo has received approval for early retirement of Cherokee Unit 3 and Valmont Unit 5 between 2015 and 2017. Amounts are presented net of accumulated depreciation.