Earnings Per Share and Common Stock (Tables)

6 Months Ended

Jun. 30, 2015

Earnings Per Share and Common Stock [Abstract]

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

			2015					2014
Reconciliation of Basic and Diluted			Dilutive					Dilutive
Earnings Per Share	Basic		Securities	Diluted		Basic		Securities	Diluted
Millions Except Per Share Amounts
Quarter ended June 30,
Net Income Attributable to ALLETE	$22.5			$22.5			$16.8			$16.8
Average Common Shares	48.6		0.1	48.7		42.1		0.2	42.3
Earnings Per Share	$0.46			$0.46			$0.40			$0.40
Six months ended June 30,
Net Income Attributable to ALLETE		$62.4			$62.4		$50.3			$50.3
Average Common Shares	47.7		0.1	47.8		41.7		0.2	41.9
Earnings Per Share		$1.31			$1.30		$1.21			$1.20