XML 27 R70.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Commitments, Guarantees and Contingencies - North Dakota Wind Development (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2012 DC Transmission Line from Square Butte [Member] kV Miles | Dec. 31, 2013 Bison Wind Energy Center [Member] MW | Dec. 31, 2013 Bison 4 Wind Project [Member] MW
--- | --- | --- | ---
North Dakota Wind Development [Line Items] |  |  |
Transmission Line Length (Miles) | 465 |  |
Transmission Line Capacity (kV) | 250 |  |
Generating Unit Capacity (MW) |  | 292 | 205
Estimated Capital Expenditures |  |  | $ 345
Capital Cost Spent to Date |  |  | 55.6
Minimum Payment Obligation in 2014 |  |  | $ 244.4

X
- Definition Capital cost spent to date for project. + References No definition available. + Details
Name: | ale_CapitalCostSpentToDate
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The estimated amount of certain future capital expenditures related to environmental compliance, regulatory matters, or other committments and/or contingencies. + References No definition available. + Details
Name: | ale_EstimatedCapitalExpenditures
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Capacity of a generating facility, unit, or project in megawatts. + References No definition available. + Details
Name: | ale_GeneratingCapacityMw
Namespace Prefix: | ale_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | ale_NorthDakotaWindDevelopmentLineItems
Namespace Prefix: | ale_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Capacity of a transmission line in kilovolts. + References No definition available. + Details
Name: | ale_TransmissionLineCapacityKv
Namespace Prefix: | ale_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Length of a transmission line in miles. + References No definition available. + Details
Name: | ale_TransmissionLineLengthMiles
Namespace Prefix: | ale_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Minimum amount of other commitment maturing in the next fiscal year following the latest fiscal year for commitments not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in this taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions. + References No definition available. + Details
Name: | us-gaap_OtherCommitmentDueInNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant