Short-Term Borrowings	12 Months Ended
Dec. 31, 2025
Short-Term Debt [Abstract]
Short-Term Borrowings	We generate short-term borrowings from our revolving credit facility, commercial paper program and accounts receivable transfer programs. 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, the issuance of letters of credit and also for general corporate purposes. Our revolving credit facility has a facility limit of $2.50 billion and is comprised of a syndicate of banks. In December 2025, we extended the termination date of our revolving credit facility to December 2030 and increased our facility limit from $1.85 billion to $2.50 billion. At December 31, 2025 and 2024, we had no outstanding borrowings under this facility. Commercial Paper Program. In February 2024, we increased our program limit from $1.50 billion to $1.85 billion. We had $736.0 million and $604.6 million of commercial paper outstanding with weighted-average interest rates of 3.92% and 4.73% as of December 31, 2025 and 2024, 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 2026 and October 2026 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, 2025, the maximum amount we could borrow related to our accounts receivable programs is $175.0 million. We had no short-term borrowings related to the securitization transactions as of December 31, 2025 and 2024, respectively. For the year ended December 31, 2025 and 2024, zero and $337.6 million, respectively, was recorded as cash flows used for 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 $1.4 million, $1.5 million, and $2.7 million for the years ended December 31, 2025, 2024 and 2023, respectively. Columbia of Ohio, NIPSCO and Columbia of Pennsylvania remain responsible for collecting 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. Items listed above are presented net in the Statements of Consolidated Cash Flows as their maturities are less than 90 days.

We generate short-term borrowings from our revolving credit facility, commercial paper program and accounts receivable transfer programs. 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, the issuance of letters of credit and also for general corporate purposes. Our revolving credit facility has a facility limit of $2.50 billion and is comprised of a syndicate of banks. In December 2025, we extended the termination date of our revolving credit facility to December 2030 and increased our facility limit from $1.85 billion to $2.50 billion. At December 31, 2025 and 2024, we had no outstanding borrowings under this facility.

Commercial Paper Program. In February 2024, we increased our program limit from $1.50 billion to $1.85 billion. We had $736.0 million and $604.6 million of commercial paper outstanding with weighted-average interest rates of 3.92% and 4.73% as of December 31, 2025 and 2024, 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 2026 and October 2026 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, 2025, the maximum amount we could borrow related to our accounts receivable programs is $175.0 million.

For the year ended December 31, 2025 and 2024, zero and $337.6 million, respectively, was recorded as cash flows used for 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 $1.4 million, $1.5 million, and $2.7 million for the years ended December 31, 2025, 2024 and 2023, respectively. Columbia of Ohio, NIPSCO and Columbia of Pennsylvania remain responsible for collecting 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.