Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2018

Regulated Operations [Abstract]

Regulatory Assets and Liabilities [Table Text Block]

Regulatory Assets and Liabilities	September 30, 2018		December 31, 2017
Millions
Non-Current Regulatory Assets
Defined Benefit Pension and Other Postretirement Benefit Plans		$214.0		$220.3
Income Taxes	107.9		112.8
Asset Retirement Obligations	31.9		29.6
Manufactured Gas Plant	8.0		8.1
PPACA Income Tax Deferral	5.0		5.0
Conservation Improvement Program	—		3.3
Other	3.8		5.6
Total Non-Current Regulatory Assets		$370.6		$384.7
Current Regulatory Liabilities (a)
Provision for Interim Rate Refund (b)		$36.7	—
Provision for Tax Reform Refund (c)	9.2		—
Transmission Formula Rates	4.4		—
Total Current Regulatory Liabilities	50.3		—
Non-Current Regulatory Liabilities
Income Taxes	398.1			$411.2
Wholesale and Retail Contra AFUDC	62.0		57.9
Plant Removal Obligations	24.1		20.3
North Dakota Investment Tax Credits	14.6		14.1
Cost Recovery Riders	11.0		2.2
Conservation Improvement Program	1.1		—
Provision for Interim Rate Refund (b)	—		23.7
Other	1.4		2.6
Total Non-Current Regulatory Liabilities	512.3		532.0
Total Regulatory Liabilities		$562.6		$532.0

(a) Current regulatory liabilities are presented within Other Current Liabilities on the Consolidated Balance Sheet.

(b) This amount is expected to be refunded to Minnesota Power’s regulated retail customers in the first quarter of 2019 and includes $20.8 million of discounts provided to EITE customers as of September 30, 2018, that will be offset against interim rate refunds ($8.6 million as of December 31, 2017). (See 2016 Minnesota General Rate Case and Energy-Intensive Trade‑Exposed Customer Rates.)

(c)

Provision for Tax Reform Refund is expected to be refunded to Minnesota Power customers in the first quarter of 2019 and SWL&P customers in 2019 pending the outcome of SWL&P’s rate filing with the PSCW. (See Tax Cuts and Jobs Act of 2017.)