Business Segment (Tables)

12 Months Ended

Dec. 31, 2022

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

Year Ended December 31	2022	2021	2020
Millions
Operating Revenue
Residential	$175.9	$160.8	$140.7
Commercial	187.2	168.6	139.5
Municipal	40.2	52.0	41.2
Industrial	589.0	565.5	432.8
Other Power Suppliers	165.8	168.7	138.8
Other	101.2	112.3	94.3
Total Regulated Operations	1,259.3	1,227.9	987.3
ALLETE Clean Energy
Long-term PSA	77.2	75.5	68.3
Sale of Wind Energy Facility	33.5	—	—
Other	7.6	11.4	11.3
Total ALLETE Clean Energy	118.3	86.9	79.6
Corporate and Other
Long-term Contract	89.2	84.4	86.0
Sale of Renewable Development Projects	73.9	—	—
Other	30.0	20.0	16.2
Total Corporate and Other	193.1	104.4	102.2
Total Operating Revenue	$1,570.7	$1,419.2	$1,169.1
Net Income Attributable to ALLETE (a)
Regulated Operations	$149.9	$129.1	$136.3
ALLETE Clean Energy	16.3	26.3	21.1
Corporate and Other (b)(c)	23.1	13.8	8.0
Total Net Income Attributable to ALLETE	$189.3	$169.2	$165.4

(a)    Includes interest expense resulting from intercompany loan agreements and allocated to certain subsidiaries. The amounts are eliminated in consolidation. 

(b)    Net Income in 2022 includes a $8.3 million after-tax expense as a result of purchase price accounting related to projects under development at the time of acquisition and $2.7 million after-tax of transaction costs related to the acquisition of New Energy.

(c)    In 2021, South Shore Energy sold a portion of its undivided ownership interest in NTEC to Basin. The closing of the transaction resulted in the recognition of an approximately $8.5 million after-tax gain which is reflected in Corporate and Other. (See Note 1. Operations and Significant Accounting Policies.)

Year Ended December 31	2022	2021	2020
Millions
Depreciation and Amortization
Regulated Operations	$171.9	$170.7	$166.9
ALLETE Clean Energy	58.6	49.2	37.9
Corporate and Other	11.7	11.8	13.0
Total Depreciation and Amortization	$242.2	$231.7	$217.8
Impairment of Property, Plant and Equipment
ALLETE Clean Energy	—	—	$12.7
Interest Expense (a)
Regulated Operations	$58.1	$57.3	$58.5
ALLETE Clean Energy	2.3	1.5	2.2
Corporate and Other	19.6	13.2	13.2
Eliminations	(4.8)	(2.9)	(8.3)
Total Interest Expense	$75.2	$69.1	$65.6
Equity Earnings
Regulated Operations	$19.3	$21.3	$22.3
Corporate and Other	(0.6)	(1.3)	(0.2)
Total Equity Earnings	$18.7	$20.0	$22.1
Income Tax Expense (Benefit)
Regulated Operations	$(10.4)	$(16.6)	$(19.4)
ALLETE Clean Energy	(15.4)	(16.6)	(23.0)
Corporate and Other	(5.4)	6.3	(1.0)
Total Income Tax Benefit	$(31.2)	$(26.9)	$(43.4)

(a)    Includes interest expense resulting from intercompany loan agreements and allocated to certain subsidiaries. The amounts are eliminated in consolidation.    

As of December 31	2022	2021
Millions
Assets
Regulated Operations	$4,291.4	$4,289.4
ALLETE Clean Energy	1,873.3	1,706.7
Corporate and Other	680.9	426.2
Total Assets	$6,845.6	$6,422.3
Capital Expenditures
Regulated Operations	$158.3	$166.8
ALLETE Clean Energy	2.2	269.9
Corporate and Other	47.6	39.7
Total Capital Expenditures	$208.1	$476.4