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Fair value of vehicle fuel and other commodity asset derivatives designated as cash flow hedging instruments which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer.

No definition available.

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Fair values as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments and which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

No definition available.

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments which are expected to exist longer than one year or beyond the normal operating cycle, if longer.

No definition available.

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Fair value of liability arising from contracts that meet the criteria of being accounted for as derivative instruments, financial instrument or contract used to mitigate a specified risk (hedge), energy marketing activities (trading activities), expected to be settled after one year or beyond the normal operating cycle, if longer. Examples of energy marketing activities include, but are not limited to, trading of electricity, coal, natural gas and oil using financial instruments, including, but not limited to, forward contracts, options and swaps.

No definition available.

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements, and purchased power agreements due within one year or within the normal operating cycle if longer.

No definition available.

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No definition available.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements, and purchased power agreements due within one year or within the normal operating cycle if longer.

No definition available.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of after one year or beyond the normal operating cycle, if longer, net of the effects of master netting arrangements, and purchased power agreements.

No definition available.

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No definition available.

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No definition available.

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Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsAssetsCurrentAtFairValueAbstract
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Fair value of commodity trading derivative assets not designated as a hedging instrument which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

No definition available.

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Fair value of natural gas commodity derivative assets not designated as a hedging instrument which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

No definition available.

Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsAssetsCurrentAtFairValueNaturalGasCommodity
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Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsAssetsNoncurrentAtFairValueAbstract
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Fair value of commodity trading derivative assets not designated as a hedging instrument which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer.

No definition available.

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Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesCurrentAtFairValueAbstract
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Fair value of commodity trading derivative liabilities not designated as a hedging instrument which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer.

No definition available.

Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesCurrentAtFairValueCommodityTrading
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Fair value of natural gas commodity derivative liabilities not designated as a hedging instrument which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer.

No definition available.

Name:	psco_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesCurrentAtFairValueNaturalGasCommodity
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Fair value of commodity trading derivative liabilities not designated as a hedging instrument which are expected to be extinguished or otherwise disposed of after one year or beyond the normal operating cycle.

No definition available.

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Carrying value as of the balance sheet date of purchased power agreements. Used to reflect the current portion of the assets expected to be realized or consumed within one year (or the normal operating cycle, if longer).

No definition available.

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Carrying value as of the balance sheet date of purchased power agreements. Used to reflect the noncurrent portion of the assets expected to be realized or consumed after one year (or the normal operating cycle, if longer).

No definition available.

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Data Type:	xbrli:monetaryItemType
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Carrying value as of the balance sheet date of purchased power agreements. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

No definition available.

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Data Type:	xbrli:monetaryItemType
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Carrying value as of the balance sheet date of purchased power agreements. Used to reflect the noncurrent portion of the liabilities (due after one year or beyond the normal operating cycle, if longer).

No definition available.

Name:	psco_PurchasedPowerAgreementsLiabilitiesNoncurrent
Namespace Prefix:	psco_
Data Type:	xbrli:monetaryItemType
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Carrying amount as of the balance sheet date of the asset arising from derivative instruments and hedging activities, which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.8)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Sum as of the balance sheet date of the (a) fair values of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and (b) the carrying amounts of the liabilities arising from financial instruments or contracts used to mitigate a specified risk (hedge), and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DerivativeInstrumentsAndHedgesLiabilities
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Carrying amount as of the balance sheet date of the assets arising from derivative contracts and hedging activities, which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682