Earnings Per Share and Common Stock (Tables)

6 Months Ended

Jun. 30, 2012

Earnings Per Share and Common Stock [Abstract]

Reconciliation of Basic and Diluted Earnings Per Share [Table Text Block]

			2012					2011
Reconciliation of Basic and Diluted			Dilutive					Dilutive
Earnings Per Share	Basic		Securities	Diluted		Basic		Securities	Diluted
Millions Except Per Share Amounts
For the Quarter Ended June 30,
Net Income Attributable to ALLETE		$14.4			$14.4		$17.0			$17.0
Common Shares	37.3		0.1	37.4		35.0		0.1	35.1
Earnings Per Share		$0.39			$0.39		$0.49			$0.48
For the Six Months Ended June 30,
Net Income Attributable to ALLETE		$38.8			$38.8		$54.2			$54.2
Common Shares	37.0		0.1	37.1		34.8		0.1	34.9
Earnings Per Share		$1.05			$1.05		$1.56			$1.55