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v3.22.0.1

Operations and Significant Accounting Policies - Balance Sheet and Income Statement Disclosures (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract] |  |  |  |  |
Cash and Cash Equivalents |  | $ 45.1 | $ 44.3 | $ 69.3 |
Restricted Cash included in Prepayments and Other |  | 0.3 | 0.8 | 2.8 |
Restricted Cash included in Other Non-Current Assets |  | 2.3 | 20.1 | 20.4 |
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows |  | 47.7 | 65.2 | 92.5 | $ 79.0
Accounts Receivable [Abstract] |  |  |  |  |
Billed |  | 100.8 | 93.5 |  |
Unbilled |  | 24.7 | 20.9 |  |
Less: Allowance for Doubtful Accounts |  | 1.8 | 2.5 |  |
Total Accounts Receivable |  | 123.7 | 111.9 |  |
Inventories – Net [Abstract] |  |  |  |  |
Fuel | [1] | 18.7 | 23.1 |  |
Materials and Supplies |  | 56.1 | 51.1 |  |
Construction of Wind Energy Facilities | [2] | 22.9 | 0.0 |  |
Total Inventories – Net |  | 97.7 | 74.2 |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Impairment of Long-Lived Assets Held-for-use |  | 0.0 | 0.0 | 0.0 |
Other Non-Current Assets [Abstract] |  |  |  |  |
Contract Asset - Noncurrent | [3] | 23.3 | 25.5 |  |
Operating Lease, Right-of-Use Asset |  | 16.4 | 22.4 |  |
ALLETE Properties |  | 19.4 | 18.2 |  |
Restricted Cash, Noncurrent |  | 2.3 | 20.1 | $ 20.4 |
Other Postretirement Benefit Plans |  | 64.8 | 34.2 |  |
Other |  | 87.5 | 86.4 |  |
Total Other Non-Current Assets |  | 213.7 | 206.8 |  |
Customer Deposits | [4] | 27.2 | 7.4 |  |
PSAs |  | 12.6 | 12.5 |  |
Manufactured Gas Plant - Current | [5] | 12.8 | 0.0 |  |
Fuel Adjustment Clause |  | 5.0 | 3.7 |  |
Operating Lease Liabilities, Current |  | 4.8 |  |  |
Redeemable Non-Controlling Interest | [6] | 30.6 | 0.0 |  |
Other |  | 40.0 | 37.2 |  |
Total Other Current Liabilities |  | 133.0 | 66.7 |  |
Asset Retirement Obligation |  | 184.5 | 166.6 |  |
PSAs |  | 39.5 | 52.1 |  |
Operating Lease Liabilities, Non-Current |  | 11.6 |  |  |
Other |  | 45.2 | 50.1 |  |
Total Other Non-Current Liabilities |  | $ 280.8 | $ 285.3 |  |
Income Taxes [Abstract] |  |  |  |  |
More-Likely-Than-Not Percentage |  | 50.00% | 50.00% |  |
Taconite Harbor [Member] | Resource Package [Member] | MPUC [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Net Book Value |  | $ 45.0 |  |  |
Boswell Unit 3 [Member] | 2021 Integrated Resource Plan [Member] | MPUC [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Net Book Value |  | 245.0 |  |  |
Boswell Unit 4 [Member] | 2021 Integrated Resource Plan [Member] | MPUC [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Net Book Value |  | 435.0 |  |  |
Other Current Liabilities |  |  |  |  |
Operating Lease Liabilities, Current |  | 4.8 | $ 5.9 |  |
Other Noncurrent Liabilities |  |  |  |  |
Operating Lease Liabilities, Non-Current |  | $ 11.6 | $ 16.5 |  |
[1] | Fuel consists primarily of coal inventory at Minnesota Power.
[2] | Project costs related to ALLETE Clean Energy’s Northern Wind and Red Barn wind projects which are expected be sold in late 2022 and 2023, respectively. (See Other Current Liabilities.)
[3] | Contract Assets include payments made to customers as an incentive to execute or extend service agreements. The contract payments are being amortized over the term of the respective agreements as a reduction to revenue.
[4] | Primarily related to deposits received by ALLETE Clean Energy for the Northern Wind and Red Barn wind projects which are expected be sold in late 2022 and 2023 respectively. (See Inventories – Net.)
[5] | The manufactured gas plant represents the current liability for remediation of a former manufactured gas plant site located in Superior, Wisconsin, and formerly operated by SWL&P. (See Note 8. Commitments, Guarantees and Contingencies.)
[6] | Amount reclassified from Non-Controlling Interest in Subsidiaries resulting from the exercise of an option to buy out a non-controlling interest, which was paid in the first quarter of 2022.

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