Operations and Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Cash, Cash Equivalents and Restricted Cash [Table Text Block]

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheet that aggregate to the amounts presented in the Consolidated Statement of Cash Flows.

Cash, Cash Equivalents and Restricted Cash	September 30, 2020	December 31, 2019	September 30, 2019	December 31, 2018
Millions
Cash and Cash Equivalents	$79.0	$69.3	$100.3	$69.1
Restricted Cash included in Prepayments and Other	3.2	2.8	3.4	1.3
Restricted Cash included in Other Non-Current Assets	2.9	20.4	31.5	8.6
Cash, Cash Equivalents and Restricted Cash on the Consolidated Statement of Cash Flows	$85.1	$92.5	$135.2	$79.0

Inventories – Net [Table Text Block]

Inventories – Net	September 30, 2020	December 31, 2019
Millions
Fuel (a)	$25.1	$25.9
Materials and Supplies	49.7	46.9
Total Inventories – Net	$74.8	$72.8

(a)    Fuel consists primarily of coal inventory at Minnesota Power.

Other Non-Current Assets [Table Text Block]

Other Non-Current Assets	September 30, 2020	December 31, 2019
Millions
Contract Assets (a)	$26.1	$28.0
Operating Lease Right-of-use Assets	24.0	28.6
ALLETE Properties	21.2	21.9
Restricted Cash	2.9	20.4
Other Postretirement Benefit Plans	38.9	37.5
Other	83.1	81.8
Total Other Non-Current Assets	$196.2	$218.2

(a)    Contract Assets consist of 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.

Other Current Liabilities [Table Text Block]

Other Current Liabilities	September 30, 2020	December 31, 2019
Millions
PSAs	$12.5	$12.3
Provision for Interim Rate Refund (a)	5.2	—
Fuel Adjustment Clause (b)	10.3	—
Operating Lease Liabilities	6.3	6.9
Other	36.4	41.2
Total Other Current Liabilities	$70.7	$60.4

(a)Provision for Interim Rate Refund represents reserves for interim rates resulting from the MPUC’s approval of Minnesota Power’s petition and proposal to resolve and withdraw its rate case. (See Note 2. Regulatory Matters.)

(b)See Note 2. Regulatory Matters.

Other Non-Current Liabilities [Table Text Block]

Other Non-Current Liabilities	September 30, 2020	December 31, 2019
Millions
Asset Retirement Obligation	$164.4	$160.3
PSAs	55.2	64.6
Operating Lease Liabilities	17.7	21.8
Other	48.2	46.3
Total Other Non-Current Liabilities	$285.5	$293.0

Other Income [Table Text Block]

Other Income
Nine Months Ended September 30,	2020	2019
Millions
Pension and Other Postretirement Benefit Plan Non-Service Credits (a)	$6.5	$5.2
Interest and Investment Income	0.4	3.3
AFUDC - Equity	1.8	1.9
Gain on Land Sales	0.5	2.1
Other	(0.1)	2.1
Total Other Income	$9.1	$14.6

(a)These are components of net periodic pension and other postretirement benefit cost other than service cost. (See Note 9. Pension and Other Postretirement Benefit Plans.)

Supplemental Statement of Cash Flows Information [Table Text Block]

Supplemental Statement of Cash Flows Information.

Nine Months Ended September 30,	2020	2019
Millions
Cash Paid for Interest – Net of Amounts Capitalized	$48.8	$53.5
Recognition of Right-of-use Assets and Lease Liabilities	—	$30.4
Noncash Investing and Financing Activities
Increase (Decrease) in Accounts Payable for Capital Additions to Property, Plant and Equipment	$(88.4)	$6.3
Capitalized Asset Retirement Costs	$2.1	$16.6
AFUDC–Equity	$1.8	$1.9