-- None. No documentation exists for this element. --

No definition available.

Name:	psco_LegalContingenciesAbstract
Namespace Prefix:	psco_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum amount of damages claimed by the plaintiff.

+ References

No definition available.

+ Details

Name:	psco_MinimumAmountOfDamagesClaimedByPlaintiff
Namespace Prefix:	psco_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

Name:	psco_NumberOfFactorsConsideredInAssessment
Namespace Prefix:	psco_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

Name:	us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=psco_PacificNorthwestFercRefundProceedingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=psco_PscoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies, Legal Contingencies (Details)	3 Months Ended		9 Months Ended		13 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Factor	Sep. 30, 2014 USD ($)	Jun. 30, 2001 USD ($)
Legal Contingencies [Abstract]
Sales to the City of Seattle	$ 1,044,704,000	$ 1,049,111,000	$ 3,132,675,000	$ 3,246,358,000
Pacific Northwest FERC Refund Proceeding
Legal Contingencies [Abstract]
Accrual for legal contingency	0		0
PSCo \| Pacific Northwest FERC Refund Proceeding
Legal Contingencies [Abstract]
Minimum amount of damages claimed by plaintiff	34,000,000		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		$ 28,000,000
Number of factors considered in assessment \| Factor			2
Accrual for legal contingency	$ 0		$ 0