XML 58 R22.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Pension and Other Postretirement Benefit Plans | 3 Months Ended
--- | ---
Mar. 31, 2015
Pension and Other Postretirement Benefit Plans [Abstract] |
Pension and Other Postretirement Benefit Plans [Text Block] | PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS
| Pension |  | Other Postretirement
Components of Net Periodic Benefit Expense (Income) | 2015 |  | 2014 |  | 2015 |  | 2014
Millions |  |  |  |  |  |  |
Three months ended March 31, |  |  |  |  |  |  |
Service Cost |  | $2.5 |  |  |  | $2.1 |  |  |  | $1.1 |  |  |  | $0.9 |
Interest Cost | 7.5 |  |  | 7.4 |  |  | 1.8 |  |  | 1.8 |
Expected Return on Plan Assets | (10.2 | ) |  | (9.6 | ) |  | (2.7 | ) |  | (2.6 | )
Amortization of Prior Service Costs (Credits) | — |  |  | 0.1 |  |  | (0.8 | ) |  | (0.6 | )
Amortization of Net Loss | 4.5 |  |  | 3.6 |  |  | 0.1 |  |  | 0.1 |
Net Periodic Benefit Expense (Income) |  | $4.3 |  |  |  | $3.6 |  |  | $(0.5) |  | $(0.4)
Employer Contributions. For the three months ended March 31, 2015, no contributions were made to our defined benefit pension plan ($19.5 million for the three months ended March 31, 2014); we do not expect to make any contributions to our defined benefit pension plan in 2015. For the three months ended March 31, 2015 and 2014, we made no contributions to our other postretirement benefit plan; we do not expect to make any contributions to our other postretirement benefit plan in 2015.

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

X
- Definition The entire disclosure for pension and other postretirement benefits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2410-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=35742057&loc=SL14450702-114947 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414199&loc=d3e39622-114963 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39675-114964 + Details
Name: | us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration