XML 72 R59.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Short-Term and Long-Term Debt (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2016 | Dec. 31, 2015
Debt Disclosure [Abstract] |  |  |  |
Short-Term Debt - Principal | $ 66.0 | [1] | $ 37.9 | [2]
Short-Term Debt - Unamortized Debt Issuance Costs | (0.6) | [1] | (0.6) | [2]
Short-Term Debt - Total | 65.4 | [1] | 37.3 | [2]
Long-term Debt - Principal | 1,510.1 |  | 1,568.7 |
Long-Term Debt - Unamortized Debt Issuance Costs | (11.2) |  | (12.0) |
Long-Term Debt - Total | 1,498.9 |  | 1,556.7 |
Total Debt - Principal | 1,576.1 |  | 1,606.6 |
Total Debt - Unamortized Debt Issuance Costs | (11.8) |  | (12.6) |
Total Debt - Total | 1,564.3 |  | $ 1,594.0 |
Proceeds from Issuance of Long-Term Debt | $ 0.0 |  |  |
[1] | Consisted of long-term debt due within one year and notes payable.
[2] | Consisted of long-term debt due within one year and notes payable.

X
- Definition Amount of short-term debt and current maturities of long-term debt before deduction of unamortized discount or premium and unamortized debt issuance costs. + References No definition available. + Details
Name: | ale_DebtCurrentGross
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the aggregate of total long-term debt, including current maturities and short-term debt, before deduction of unamortized discount or premium and unamortized debt issuance expense. + References No definition available. + Details
Name: | ale_DebtLongTermandShortTermCombinedAmountGross
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of short-term debt or the current maturities of long-term debt. + References No definition available. + Details
Name: | ale_UnamortizedDebtIssuanceExpenseDebtCurrent
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of long-term debt excluding current maturities. + References No definition available. + Details
Name: | ale_UnamortizedDebtIssuanceExpenseLongTermDebtExcludingCurrentMaturities
Namespace Prefix: | ale_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DebtDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the aggregate of total long-term debt, including current maturities and short-term debt. + References No definition available. + Details
Name: | us-gaap_DebtLongtermAndShorttermCombinedAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow from amounts received from a long-term debt instrument secured by a first mortgage deed of trust, containing a pledge of real property. The lender has the highest claim on the property in case of default. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
Name: | us-gaap_ProceedsFromIssuanceOfFirstMortgageBond
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant