XML 25 R50.htm IDEA: XBRL DOCUMENT v2.4.0.8

Regulatory Matters - Conservation Improvement Program (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Conservation Improvement Program [Abstract]
CIP Energy-Savings Goal	1.50%
Conservation Improvement Program Financial Incentive	$ 8.7	$ 7.1

X

- Definition

Minnesota's Next Generation Act of 2007 introduced an energy-savings goal of 1.5 percent of net gross annual retail electric energy sales beginning with the 2010 program year.

+ References

No definition available.

+ Details

Name:	ale_CIPEnergySavingsGoal
Namespace Prefix:	ale_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	ale_ConservationImprovementProgramAbstract
Namespace Prefix:	ale_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Conservation Improvement Program Financial Incentive

+ References

No definition available.

+ Details

Name:	ale_ConservationImprovementProgramFinancialIncentive
Namespace Prefix:	ale_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration