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Commitments, Guarantees and Contingencies - Transmission (Details) (USD $) In Millions, unless otherwise specified | Mar. 31, 2012 | Dec. 31, 2011
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Transmission [Line Items] |  |
MPUC, Billing Factor, Approval Date | May 2011 |
MPUC, Updated Billing Factor, Filing Date | June 2011 |
MPUC, Updated Billing Factor, Expected Approval Date | 2012 |
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 | $ 33.5 | $ 27.8
CapX2020 Fargo to St. Cloud Project [Member] |  |
Transmission [Line Items] |  |
MPUC, Route Permit, Approval Date | June 2011 |
In Service Date | 2015 |
CapX2020 Monticello to St. Cloud Project [Member] |  |
Transmission [Line Items] |  |
Transmission Line Length (Miles) | 28 |
Transmission Line Capacity (kV) | 345 |
MPUC, Route Permit, Approval Date | July 2010 |
Project Completion Date | December 2011 |
CapX2020 Bemidji to Grand Rapids Project [Member] |  |
Transmission [Line Items] |  |
Transmission Line Length (Miles) | 70 |
Transmission Line Capacity (kV) | 230 |
MPUC, Route Permit, Approval Date | November 2010 |
Construction Start Date | January 2011 |
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
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- Definition Date/expected date of start of construction for a project. + References No definition available. + Details
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- Definition Date/expected date an asset will be in service. + References No definition available. + Details
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X
- Definition The maximum amount expected to be invested in transmission line projects. + References No definition available. + Details
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- Definition The minimum amount expected to be invested in transmission line projects. + References No definition available. + Details
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X
- Definition Date/expected date of approval by the Minnesota Public Utilities Commission (MPUC) of billing factor. + References No definition available. + Details
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- Definition Date/expected date of approval by the Minnesota Public Utilities Commission (MPUC) of route permit. + References No definition available. + Details
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- Definition Date/expected date of approval by the Minnesota Public Utilities Commission of updated billing factor. + References No definition available. + Details
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- Definition Filing date of petition to the Minnesota Public Utilities Commission (MPUC) seeking updated billing factor approval. + References No definition available. + Details
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Namespace Prefix: | ale_
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X
- Definition Number of projects. + References No definition available. + Details
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- Definition Date/expected date of project completion. + References No definition available. + Details
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- Definition Capacity of a transmission line in kilovolts. + References No definition available. + Details
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- Details
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- Definition Length of a transmission line in miles. + References No definition available. + Details
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