Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets [Table Text Block]

The regulatory assets and regulatory liabilities resulting from our application of the provisions of ASC Topic 980, Regulated Operations, included in the accompanying Consolidated Balance Sheet at December 31, 2019 and December 31, 2018 are as follows (in millions):

Regulatory Assets	2019		2018
Grossed-up deferred taxes on equity funds used during construction	$	37.5	$	39.0
Asset retirement obligations	147.6		171.9
Asset retirement costs - Eminence	42.2		45.5
Deferred cash out	64.4		54.9
Fuel cost	40.2		61.2
Electric power cost	8.4		—
Slug catcher	6.6		—
Other	13.5		12.7
Total Regulatory Assets	$	360.4	$	385.2

Schedule of Regulatory Liabilities [Table Text Block]

Regulatory Liabilities	2019		2018
Negative salvage	$	482.6	$	444.5
Deferred taxes - liability	423.5		450.2
Sentinel meter station depreciation	6.6		6.4
Postretirement benefits other than pension	68.0		79.8
Pension - unamortized liability	43.3		48.5
Other	0.3		2.6
Total Regulatory Liabilities	$	1,024.3	$	1,032.0