Investments

9 Months Ended

Sep. 30, 2018

Investments [Abstract]

Investments [Text Block]

INVESTMENTS

Investments. As of September 30, 2018, the investment portfolio included the legacy real estate assets of ALLETE Properties, debt and equity securities consisting primarily of securities held in other postretirement plans to fund employee benefits, the cash equivalents within these plans and other assets consisting primarily of land in Minnesota.

Other Investments	September 30, 2018		December 31, 2017
Millions
ALLETE Properties		$25.4		$26.4
Available-for-sale Securities (a)	21.0		19.1
Cash Equivalents	1.5		3.8
Other	3.8		3.8
Total Other Investments		$51.7		$53.1

(a) As of September 30, 2018, the aggregate amount of available-for-sale corporate and governmental debt securities maturing in one year or less was $1.8 million, in one year to less than three years was $3.5 million, in three years to less than five years was $1.9 million and in five or more years was $1.1 million.

Available-for-Sale Securities. We account for our available-for-sale securities portfolio in accordance with the guidance for certain investments in debt and equity securities. Our available-for-sale securities portfolio consisted primarily of securities held in other postretirement plans to fund employee benefits. Gross realized and unrealized gains and losses on our available-for-sale securities were immaterial for the quarter and nine months ended September 30, 2018, and 2017.