XML 67 R54.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Regulatory Matters - MISO Return on Equity Complaints (Details) - FERC [Member] | Jun. 30, 2017
--- | ---
Return on Equity Complaint 1 [Member] |
Loss Contingencies [Line Items] |
Requested Return on Equity Filed with the FERC by Third Party | 9.15%
FERC Authorized Return on Common Equity | 10.32%
FERC Authorized Return on Equity Including Incentive Adder | 10.82%
Return on Equity Complaint 2 [Member] |
Loss Contingencies [Line Items] |
Requested Return on Equity Filed with the FERC by Third Party | 8.67%
Proposed Return on Equity by Federal Administrative Law Judge | 9.70%
Proposed Return on Equity by Federal Administrative Law Judge Including Incentive Adder | 10.20%

X
- Definition FERC Authorized Return on Common Equity + References No definition available. + Details
Name: | ale_FERCAuthorizedReturnonCommonEquity
Namespace Prefix: | ale_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition FERC Authorized Return on Equity, Including Incentive Adder + References No definition available. + Details
Name: | ale_FERCAuthorizedReturnonEquityIncludingIncentiveAdder
Namespace Prefix: | ale_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The proposed return on common equity by regulatory organization + References No definition available. + Details
Name: | ale_ProposedReturnonCommonEquitybyRegulatoryOrganization
Namespace Prefix: | ale_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Proposed Return on Equity by Regulatory Organization, Including Incentive Adder + References No definition available. + Details
Name: | ale_ProposedReturnonEquitybyRegulatoryOrganizationIncludingIncentiveAdder
Namespace Prefix: | ale_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The requested return on common equity, which would be dedicated to the utilities within the regulatory organizations jurisdiction. + References No definition available. + Details
Name: | ale_RequestedReturnonCommonEquityFiledwithRegulatoryOrganization
Namespace Prefix: | ale_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=ale_FERCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=ale_FERCComplaint1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=ale_FERCComplaint2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |