Jointly-Owned Facilities and Assets (Tables)

12 Months Ended

Dec. 31, 2021

Jointly-Owned Facilities and Assets [Abstract]

Jointly-Owned Facilities and Assets [Table Text Block]

Minnesota Power’s investments in jointly-owned facilities and assets and the related ownership percentages are as follows:

Regulated Utility Plant	Plant in Service	Accumulated Depreciation	Construction Work in Progress	% Ownership
Millions
As of December 31, 2021
Boswell Unit 4	$682.7	$311.1	$30.1	80
Transmission Assets	101.0	18.5	—	9.3 - 14.7
Total	$783.7	$329.6	$30.1
As of December 31, 2020
Boswell Unit 4	$663.8	$288.8	$15.0	80
Transmission Assets	101.0	16.0	—	9.3 - 14.7
Total	$764.8	$304.8	$15.0