Investments (Tables)

6 Months Ended

Jun. 30, 2017

Investments [Abstract]

Other Investments [Table Text Block]

Other Investments	June 30, 2017		December 31, 2016
Millions
ALLETE Properties		$29.5		$31.7
Available-for-sale Securities (a)	20.6		18.8
Cash Equivalents	2.4		1.3
Other	3.7		3.8
Total Other Investments		$56.2		$55.6

(a) As of June 30, 2017, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $0.6 million, in one year to less than three years was $2.7 million, in three years to less than five years was $6.8 million and in five or more years was $2.9 million.