Name:	gxp_ContractuallySpecifiedServicingFeesPercentageAmount
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Balance Type:	na
Period Type:	duration

Maximum amount of outstanding principal under receivables agreement

No definition available.

Name:	gxp_MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreement
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Maximum amount of outstanding principal under receivables agreement from June 1 to October 31 of each year.

No definition available.

Name:	gxp_MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromJune1ToOctober31OfEachYear
Namespace Prefix:	gxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum amount of outstanding principal under receivables agreement from November 1 to May 31 of each year

No definition available.

Name:	gxp_MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromNovember1ToMay31OfEachYear
Namespace Prefix:	gxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Carrying amount of financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=7523297&loc=SL6224234-111729

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Carrying amount of liabilities associated with financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented.