XML 44 R32.htm IDEA: XBRL DOCUMENT v3.23.1

Operations and Significant Accounting Policies - Non-Controlling Interest (Details)	3 Months Ended
	Mar. 31, 2023 MW
Glen Ullin Energy Center [Member]
Non-Controlling Interest Details [Line Items]
Generating Capacity Subject to Tax Equity Financing	106
South Peak [Member]
Non-Controlling Interest Details [Line Items]
Generating Capacity Subject to Tax Equity Financing	80
Diamond Spring [Member]
Non-Controlling Interest Details [Line Items]
Generating Capacity Subject to Tax Equity Financing	303
Caddo [Member]
Non-Controlling Interest Details [Line Items]
Generating Capacity Subject to Tax Equity Financing	303
Nobles 2 [Member]
Non-Controlling Interest Details [Line Items]
Generating Capacity Subject to Tax Equity Financing	250

X

- Definition

Generating Capacity Subject to Tax Equity Financing

+ References

No definition available.

+ Details

Name:	ale_GeneratingCapacitySubjecttoTaxEquityFinancing
Namespace Prefix:	ale_
Data Type:	dtr-types:powerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

[Line Items] for Non-Controlling Interest Details [Table]

+ References

No definition available.

+ Details

Name:	ale_NonControllingInterestDetailsLineItems
Namespace Prefix:	ale_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ale_GeneratingFacilityAxisAxis=ale_GlenUllinEnergyCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ale_GeneratingFacilityAxisAxis=ale_SouthPeakMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ale_GeneratingFacilityAxisAxis=ale_DiamondSpringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ale_GeneratingFacilityAxisAxis=ale_CaddoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ale_GeneratingFacilityAxisAxis=ale_Nobles2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: