Business Segments (Tables)

12 Months Ended

Dec. 31, 2013

Business Segments [Abstract]

Business Segments [Table Text Block]

	Consolidated			Regulated Operations			Investments and Other
Millions
2011
Operating Revenue		$928.2			$851.9			$76.3
Fuel and Purchased Power Expense	306.6			306.6			—
Operating and Maintenance Expense	381.2			301.5			79.7
Depreciation Expense	90.4			85.4			5.0
Operating Income (Loss)	150.0			158.4			(8.4		)
Interest Expense	(43.6		)	(35.8		)	(7.8		)
Equity Earnings in ATC	18.4			18.4			—
Other Income	4.4			2.6			1.8
Income (Loss) Before Non-Controlling Interest and Income Taxes	129.2			143.6			(14.4		)
Income Tax Expense (Benefit)	35.6			43.2			(7.6		)
Net Income (Loss)	93.6			100.4			(6.8		)
Less: Non-Controlling Interest in Subsidiaries	(0.2		)	—			(0.2		)
Net Income (Loss) Attributable to ALLETE		$93.8			$100.4		$(6.6)
Total Assets		$2,876.0			$2,579.8			$296.2
Capital Additions		$246.8			$228.0			$18.8

	Consolidated			Regulated Operations			Investments and Other
Millions
2013
Operating Revenue		$1,018.4			$925.5			$92.9
Fuel and Purchased Power Expense	334.8			334.8			—
Operating and Maintenance Expense	412.9			322.4			90.5
Depreciation Expense	116.6			110.2			6.4
Operating Income (Loss)	154.1			158.1			(4.0		)
Interest Expense	(50.3		)	(42.1		)	(8.2		)
Equity Earnings in ATC	20.3			20.3			—
Other Income	9.3			4.7			4.6
Income (Loss) Before Income Taxes	133.4			141.0			(7.6		)
Income Tax Expense (Benefit)	28.7			36.1			(7.4		)
Net Income (Loss)		$104.7			$104.9		$(0.2)
Total Assets		$3,476.8			$3,160.8			$316.0
Capital Additions		$339.5			$326.3			$13.2

	Consolidated			Regulated Operations			Investments and Other
Millions
2012
Operating Revenue		$961.2			$874.4			$86.8
Fuel and Purchased Power Expense	308.7			308.7			—
Operating and Maintenance Expense	397.1			310.0			87.1
Depreciation Expense	100.2			93.9			6.3
Operating Income (Loss)	155.2			161.8			(6.6		)
Interest Expense	(45.5		)	(39.8		)	(5.7		)
Equity Earnings in ATC	19.4			19.4			—
Other Income	6.0			5.1			0.9
Income (Loss) Before Income Taxes	135.1			146.5			(11.4		)
Income Tax Expense (Benefit)	38.0			50.4			(12.4		)
Net Income		$97.1			$96.1			$1.0
Total Assets		$3,253.4			$2,962.4			$291.0
Capital Additions		$432.2			$418.2			$14.0