Short-Term Borrowings	12 Months Ended
Short-Term Borrowings	Dec. 31, 2023
Short-Term Debt [Abstract]
Short-Term Borrowings	We generate short-term borrowings from our revolving credit facility, commercial paper program, accounts receivable transfer programs, and term credit agreements. Each of these borrowing sources is described further below. Revolving Credit Facility. We maintain a revolving credit facility to fund ongoing working capital requirements, including the provision of liquidity support for our commercial paper program, provide for issuance of letters of credit, and also for general corporate purposes. Our revolving credit facility has a program limit of $1.85 billion and is comprised of a syndicate of banks. At December 31, 2023 and 2022, we had no outstanding borrowings under this facility. Commercial Paper Program. At December 31, 2023, our commercial paper program had a program limit of up to $1.5 billion. On February 9, 2024, we increased the program limit to $1.85 billion. We had $1,061.0 million and $415.0 million of commercial paper outstanding with weighted-average interest rates of 5.65% and 4.60% as of December 31, 2023 and 2022, respectively. Accounts Receivable Transfer Programs. Columbia of Ohio, NIPSCO, and Columbia of Pennsylvania each maintain a receivables agreement whereby they transfer their customer accounts receivables to third party financial institutions through consolidated special purpose entities. The three agreements expire between May 2024 and October 2024 and may be further extended if mutually agreed to by the parties thereto. All receivables transferred to third parties are valued at face value, which approximates fair value due to their short-term nature. The amount of the undivided percentage ownership interest in the accounts receivables transferred is determined in part by required loss reserves under the agreements. Transfers of accounts receivable are accounted for as secured borrowings resulting in the recognition of short-term borrowings on the Consolidated Balance Sheets. As of December 31, 2023, the maximum amount of debt that could be recognized related to our accounts receivable programs is $383.9 million. We had $337.6 million and $347.2 million short-term borrowings related to the securitization transactions as of December 31, 2023 and 2022, respectively. For the year ended December 31, 2023, $9.6 million was recorded as cash flows used for financing activities related to the change in short-term borrowings due to securitization transactions. For the year ended December 31, 2022, $347.2 million was recorded as cash flows from financing activities related to the change in short-term borrowings due to securitization transactions. For the accounts receivable transfer programs, we pay used facility fees for amounts borrowed, unused commitment fees for amounts not borrowed, and upfront renewal fees. Fees associated with the securitization transactions were $2.7 million, $2.5 million, and $1.4 million for the years ended December 31, 2023, 2022 and 2021, respectively. Columbia of Ohio, NIPSCO and Columbia of Pennsylvania remain responsible for collecting on the receivables securitized, and the receivables cannot be transferred to another party. Refer to Note 23, "Interest Expense, Net," for additional information on securitization transaction fees. Term Credit Agreements. On December 20, 2022, we entered into a $1.0 billion term credit agreement with a syndicate of banks. On October 5, 2023, we entered into an amendment with the syndicate of banks to, among other things, extend the maturity date of the agreement from December 19, 2023 to March 15, 2024. With the amendment, we triggered extinguishment accounting and recorded an immaterial loss on extinguishment of debt in the fourth quarter of 2023. Interest charged on the borrowings depended on the variable rate structure elected at the time of each borrowing. The available variable rate structures from which we could choose were defined in the agreement. Under the agreement, we borrowed $1.0 billion on December 20, 2022 with an interest rate of SOFR plus 105 basis points. We had $1.0 billion outstanding under this agreement with interest rates of 6.41% and 5.37% as of December 31, 2023 and 2022, respectively. On November 9, 2023, we entered into a $250.0 million term credit agreement with a bank. The agreement had a maturity date of November 7, 2024 and interest charged on the borrowings depended on the variable rate structure elected at the time of each borrowing. The available variable rate structures from which we could choose were defined in the agreement. On December 6, 2023, we entered into an augmenting lender supplement to the agreement with a syndicate of banks for an additional $400.0 million. Under the agreement, we borrowed $250.0 million on November 9, 2023 and $400.0 million on December 6, 2023 with an interest rate of SOFR plus 115 basis points. We had $650.0 million outstanding under this agreement with an interest rate of 6.50% as of December 31, 2023. On January 3, 2024, we terminated and repaid in full our $1.0 billion term credit agreement and our $650.0 million term credit agreement. Items listed above, excluding the term credit agreements, are presented net in the Statements of Consolidated Cash Flows as their maturities are less than 90 days.