XML 17 R55.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Commitments, Guarantees and Contingencies - Transmission (Details) (USD $) In Millions, unless otherwise specified | Jun. 30, 2012 | Dec. 31, 2011
--- | --- | ---
Transmission [Line Items] |  |
Number of CapX2020 Projects | 3 |
Minimum Amount Expected to be Invested in Transmission Projects | $ 100 |
Maximum Amount Expected to be Invested in Transmission Projects | 125 |
Capital Cost Spent to Date | $ 39.6 | $ 27.8
CapX2020 Monticello to St. Cloud Project [Member] |  |
Transmission [Line Items] |  |
Transmission Line Length (Miles) | 28 |
Transmission Line Capacity (kV) | 345 |
CapX2020 Bemidji to Grand Rapids Project [Member] |  |
Transmission [Line Items] |  |
Transmission Line Length (Miles) | 70 |
Transmission Line Capacity (kV) | 230 |
CapX2020 Fargo to Monticello Projects [Member] |  |
Transmission [Line Items] |  |
Transmission Line Length (Miles) | 238 |
Transmission Line Capacity (kV) | 345 |

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 maximum amount expected to be invested in transmission line projects. + References No definition available. + Details
Name: | ale_MaximumAmountExpectedToBeInvestedInTransmissionProjects
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The minimum amount expected to be invested in transmission line projects. + References No definition available. + Details
Name: | ale_MinimumAmountExpectedToBeInvestedInTransmissionProjects
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of projects. + References No definition available. + Details
Name: | ale_NumberOfProjects
Namespace Prefix: | ale_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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

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