Investments (Tables)

3 Months Ended

Mar. 31, 2016

Investments [Abstract]

Other Investments [Table Text Block]

Other Investments	March 31, 2016		December 31, 2015
Millions
ALLETE Properties		$49.1		$50.1
Available-for-sale Securities (a)	17.4		18.5
Cash Equivalents	2.5		2.0
Other	3.9		4.0
Total Other Investments		$72.9		$74.6

(a) As of March 31, 2016, the aggregate amount of available-for-sale corporate debt securities maturing in one year or less was zero, in one year to less than three years was $1.6 million, in three years to less than five years was $4.1 million, and in five or more years was $4.7 million.