Rate and Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2019

Regulated Operations [Abstract]

Schedule of regulatory assets

We have recorded certain costs as regulatory assets because we expect full recovery of, or are currently recovering, these costs in the rates we charge customers. These deferred costs have been excluded from rate base and, therefore, we are not earning a return on the unamortized balances. These items are detailed as follows:

	(Thousands of Dollars)
	December 31,				Remaining
Regulatory Assets	2018		2017		Recovery Periods
Retirement Benefits	$	44,281	$	39,158	Various
Income Taxes		60,151		55,232	Various
Rate Cases, Tank Painting, and Other		6,047		4,846	2-10 years
Total	$	110,479	$	99,236