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Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Related Party Transaction [Line Items]
Accounts Payable	$ 139,224		$ 151,278
Operating Revenues	365,736	$ 452,756
Related Party
Related Party Transaction [Line Items]
Accounts Receivable, Net	15,000		10,000
Accounts Payable	8,000		2,000
Related Party \| Common Costs, UNS Energy Affiliates
Related Party Transaction [Line Items]
Common costs	6,000	6,000
Related Party \| Transmission Revenues, UNS Electric
Related Party Transaction [Line Items]
Operating Revenues	2,000	2,000
Related Party \| Wholesale Revenues, UNS Electric
Related Party Transaction [Line Items]
Operating Revenues	1,000	2,000
Related Party \| Corporate Services, UNS Energy
Related Party Transaction [Line Items]
Corporate services	$ 3,000	3,000
Massachusetts formula - TEP's allocation (percentage)	84.00%
Management fee	$ 3,000	2,000
Related Party \| Capacity Charges , UNS Gas
Related Party Transaction [Line Items]
Capacity charges	1,000	1,000
Related Party \| Purchased Power, UNS Electric
Related Party Transaction [Line Items]
Purchased power	1,000	$ 0
Related Party \| UNS Energy
Related Party Transaction [Line Items]
Accounts Receivable, Net	8,000		1,000
Accounts Payable	7,000		1,000
Related Party \| UNS Electric
Related Party Transaction [Line Items]
Accounts Receivable, Net	5,000		7,000
Accounts Payable	1,000		1,000
Related Party \| UNS Gas
Related Party Transaction [Line Items]
Accounts Receivable, Net	$ 2,000		$ 2,000