Regulatory Matters (Regulatory Matters Narrative - Piedmont) (Details)	Oct. 10, 2022
Piedmont \| Tennessee Annual Review Mechanism \| TPUC
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage (as a percent)	9.80%

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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