SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2023
Significant Accounting Policies [Line Items]
Segments	Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas primarily to residential, commercial and transportation customers. Our accounting policies are the same as those described in Note 1 of the Notes to Consolidated Financial Statements in our Annual Report. We evaluate our financial performance principally on net income. For the three and nine months ended September 30, 2023 and 2022, we had no single external customer from which we received 10 percent or more of our gross revenues.
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block]	Accounts Receivable, Net - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered. We assess the creditworthiness of our customers. Those customers who do not meet minimum standards may be required to provide security, including deposits and other forms of collateral, when appropriate and allowed by our tariffs. With approximately 2.3 million customers across three states, we are not exposed materially to a concentration of credit risk. We maintain an allowance for doubtful accounts based upon factors surrounding the credit risk of customers, historical trends, consideration of the current environment and other information. We recover natural gas costs related to accounts written off when they are deemed uncollectible through the purchased-gas cost adjustment mechanisms in each of our jurisdictions. At September 30, 2023 and December 31, 2022, our allowance for doubtful accounts was $14.5 million and $16.7 million, respectively.
Reclassification, Comparability Adjustment	Reclassifications - A reclassification has been made in the prior-year financial statements to conform to the current-year presentation. We have updated our consolidated balance sheet at December 31, 2022, to disaggregate “current maturities of other long-term debt,” which had previously been included in “other current liabilities,” to conform to our current-year presentation.