Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Total consolidated (as applicable) capitalization of the entity which is comprised of its short-term debt, long-term debt and equity instruments.

No definition available.

Name:	xel_CapitalizationShortTermDebtLongTermDebtAndEquity
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The actual ratio of equity to total capitalization, excluding short-term debt.

No definition available.

Name:	xel_EquityToTotalCapitalizationRatioExcludingShort-TermDebt
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The high end of the range of the ratio of equity to total capitalization, excluding short-term debt, required to be maintained by the entity in order to pay dividends.

No definition available.

Name:	xel_EquityToTotalCapitalizationRatioExcludingShort-TermDebtHighEndOfRange
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The low end of the range of the ratio of equity to total capitalization, excluding short-term debt, required to be maintained by the entity in order to pay dividends.

No definition available.

Name:	xel_EquityToTotalCapitalizationRatioExcludingShort-TermDebtLowEndOfRange
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The high end of the range of the ratio of equity to net capital required to be maintained by the entity to engage in issuance of long-term debt securities.

No definition available.

Name:	xel_EquityToTotalCapitalizationRatioHighEndOfRange
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The low end of the range of the ratio of equity to net capital required to be maintained by the entity to engage in issuance of long-term debt securities.

No definition available.

Name:	xel_EquityToTotalCapitalizationRatioLowEndOfRange
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Equity-to-total capitalization ratio is equal to (i) common stock plus surplus divided by (ii) the sum of common stock plus surplus plus long-term debt.

No definition available.

Name:	xel_Equitytototalcapitalizationratio
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Maximum additional amount of long-term debt the entity is authorized to issue, subject to the jurisdiction of the applicable state regulatory commissions and/or the Federal Energy Regulatory Commission under the Federal Power Act.

No definition available.

Name:	xel_MaximumAdditionalLongTermDebtAuthorizedForIssuance
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum additional amount of short-term debt the entity is authorized to issue, subject to the jurisdiction of they applicable state regulatory commissions and/or the Federal Energy Regulatory Commission under the Federal Power Act.

No definition available.

Name:	xel_MaximumAdditionalShortTermDebtAuthorizedForIssuance
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum annual dividends which can be paid by the entity if its calendar year average equity-to-total capitalization ratio is or falls below the state commission authorized level.

No definition available.

Name:	xel_MaximumAnnualDividendsThatCanBePaidIfEquityCapitalizationRatioConditionIsNotMet
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The maximum percentage of short-term debt to capitalization which the entity cannot exceed in order to issue additional short-term debt.

No definition available.

Name:	xel_MaximumPercentageOfShortTermDebtToTotalCapitalization
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Maximum Percentage of long term debt to total capitalization

No definition available.

Name:	xel_MaximumPercentageoflongtermdebttototalcapitalization
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The maximum total capitalization allowed for the entity.

No definition available.

Name:	xel_MaximumTotalCapitalization
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum calendar year average ratio of equity to total capitalization authorized by the state commission to be maintained by the entity in order to pay a maximum stated amount of dividends.

No definition available.

Name:	xel_MinimumCalendarYearAverageEquityToTotalCapitalizationRatioAuthorizedByStateCommission
Namespace Prefix:	xel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Unrestricted Retained Earnings Per State Regulatory Commissions Dividend Restrictions

No definition available.

Name:	xel_UnrestrictedRetainedEarningsPerStateRegulatoryCommissionsDividendRestrictions
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

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

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