XML 63 R56.htm IDEA: XBRL DOCUMENT v2.4.1.9
Regulatory Matters - Regulatory Assets and Liabilities (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Regulatory Assets and Liabilities [Line Items]    
Current Regulatory Asset $ 16.3us-gaap_RegulatoryAssetsCurrent $ 23.0us-gaap_RegulatoryAssetsCurrent
Non-Current Regulatory Asset 357.3us-gaap_RegulatoryAssetsNoncurrent 263.8us-gaap_RegulatoryAssetsNoncurrent
Total Regulatory Assets 373.6us-gaap_RegulatoryAssets 286.8us-gaap_RegulatoryAssets
Non-Current Regulatory Liability 94.2us-gaap_RegulatoryLiabilityNoncurrent 81.0us-gaap_RegulatoryLiabilityNoncurrent
Types of Net Regulatory Assets Earning Returns No regulatory assets or liabilities are currently earning a return.  
Wholesale and Retail Contra AFUDC [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Liability 42.9us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= ale_WholesaleAndRetailContraAfudcMember		 19.7us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= ale_WholesaleAndRetailContraAfudcMember
Plant Removal Obligations [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Liability 22.8us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_RemovalCostsMember		 19.7us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_RemovalCostsMember
Income Taxes [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Liability 13.4us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_DeferredIncomeTaxChargesMember		 17.0us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_DeferredIncomeTaxChargesMember
Defined Benefit Pension and Other Postretirement Plans [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Liability 3.5us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_PensionAndOtherPostretirementPlansCostsMember		 [1] 16.3us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_PensionAndOtherPostretirementPlansCostsMember		 [1]
Other [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Liability 11.6us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_OtherRegulatoryAssetsLiabilitiesMember		 8.3us-gaap_RegulatoryLiabilityNoncurrent
/ us-gaap_RegulatoryLiabilityAxis
= us-gaap_OtherRegulatoryAssetsLiabilitiesMember
Deferred Fuel Adjustment Clause [Member]    
Regulatory Assets and Liabilities [Line Items]    
Current Regulatory Asset 16.3us-gaap_RegulatoryAssetsCurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_DeferredFuelCostsMember		 [2] 23.0us-gaap_RegulatoryAssetsCurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_DeferredFuelCostsMember		 [2]
Defined Benefit Pension and Other Postretirement Plans [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset 223.9us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_PensionAndOtherPostretirementPlansCostsMember		 [1] 164.1us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_PensionAndOtherPostretirementPlansCostsMember		 [1]
Income Taxes [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset 46.6us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_DeferredIncomeTaxChargesMember		 35.3us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_DeferredIncomeTaxChargesMember
Asset Retirement Obligation [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset 17.8us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_AssetRetirementObligationCostsMember		 16.0us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_AssetRetirementObligationCostsMember
Cost Recovery Riders [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset 59.7us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= ale_CurrentCostRecoveryRiderMember		 [3] 39.6us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= ale_CurrentCostRecoveryRiderMember		 [3]
PPACA Income Tax Deferral [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset 5.0us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= ale_MedicarePartDRegulatoryAssetMember		 5.0us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= ale_MedicarePartDRegulatoryAssetMember
Other [Member]    
Regulatory Assets and Liabilities [Line Items]    
Non-Current Regulatory Asset $ 4.3us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_OtherRegulatoryAssetsLiabilitiesMember		 $ 3.8us-gaap_RegulatoryAssetsNoncurrent
/ us-gaap_RegulatoryAssetAxis
= us-gaap_OtherRegulatoryAssetsLiabilitiesMember
[1] Defined benefit pension and other postretirement items included in our Regulated Operations, which are otherwise required to be recognized in accumulated other comprehensive income, are recognized as regulatory assets or regulatory liabilities on the Consolidated Balance Sheet. (See Note 17. Pension and Other Postretirement Benefit Plans.)
[2] Current regulatory assets are included in Prepayments and Other on the Consolidated Balance Sheet.
[3] The cost recovery rider regulatory assets are due to capital expenditures related to our Bison Wind Energy Center, investment in CapX2020 projects, and the Boswell Unit 4 environmental upgrade and are recognized in accordance with the accounting standards for alternative revenue programs.