XML 51 R72.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Commitments, Guarantees and Contingencies - Coal, Rail and Shipping Contracts (Details) (Coal Supply and Transportation [Member], USD $) In Millions, unless otherwise specified | Mar. 31, 2015
--- | ---
Coal Supply and Transportation [Member] |
Coal, Rail and Shipping Contracts [Line Items] |
Coal Supply and Transportation Agreements, Minimum Annual Payment Obligation for Remainder of 2015 | $ 42.3 us-gaap_UnrecordedUnconditionalPurchaseObligationDueInRemainderOfFiscalYear / us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis = ale_CoalAndTransportationMember
Coal Supply and Transportation Agreements, Minimum Annual Payment Obligation in 2016 | 27.0 us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary / us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis = ale_CoalAndTransportationMember
Coal Supply and Transportation Agreements, Minimum Annual Payment Obligation in 2017 | 27.6 us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary / us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis = ale_CoalAndTransportationMember
Coal Supply and Transportation Agreements, Minimum Annual Payment Obligation in 2018 | $ 28.4 us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary / us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis = ale_CoalAndTransportationMember

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References No definition available. + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationDueInRemainderOfFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration