Name:	psco_LegalContingenciesAbstract
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The minimum amount of damages claimed by the plaintiff.

+ References

No definition available.

+ Details

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- Definition

The number of factors considered in the assessment of estimating an amount or range of reasonably possible loss by the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	psco_
Data Type:	xbrli:integerItemType
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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

+ Details

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Balance Type:	debit
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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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- Details

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- Details

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Commitments and Contingencies, Legal Contingencies (Details) (USD $)	3 Months Ended		13 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jun. 30, 2001
Legal Contingencies [Abstract]
Sales to the City of Seattle	$ 1,135,450,000us-gaap_Revenues	$ 1,203,543,000us-gaap_Revenues
Pacific Northwest FERC Refund Proceeding
Legal Contingencies [Abstract]
Accrual for legal contingency	0
PSCo \| Pacific Northwest FERC Refund Proceeding
Legal Contingencies [Abstract]
Minimum amount of damages claimed by plaintiff	34,000,000
Sales to the City of Seattle			50,000,000
Estimated City of Seattle's claim for refunds not including interest	28,000,000
Number of factors considered in assessment	2
Accrual for legal contingency	$ 0