Summary Of Significant Accounting Policies (Policies)	2 Months Ended
Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Accounting, Policy	The Condensed Consolidated Financial Statements have not been audited. We have prepared the unaudited Condensed Consolidated Financial Statements under the rules of the Securities and Exchange Commission (SEC). Therefore, certain financial information and note disclosures normally included in annual financial statements prepared in conformity with generally accepted accounting principles (GAAP) in the United States of America are omitted in this interim report under these SEC rules and regulations.
Consolidation, Policy	The Condensed Consolidated Financial Statements reflect the accounts of Piedmont and its wholly owned subsidiaries whose financial statements are prepared for the same reporting period as Piedmont using consistent accounting policies. Inter-company transactions have been eliminated in consolidation where appropriate; however, we have not eliminated inter-company profit on sales to affiliates and costs from affiliates in accordance with accounting regulations prescribed under rate-based regulation. Investments in unconsolidated affiliates, or joint ventures, are accounted for under the equity method as we do not have controlling voting interests or otherwise exercise control over the management of such companies.
Use of Estimates, Policy	In accordance with GAAP, we make certain estimates and assumptions regarding reported amounts of assets, liabilities, revenues and expenses and the related disclosures, using historical experience and other assumptions that we believe are reasonable at the time. Our estimates may involve complex situations requiring a high degree of judgment in the application and interpretation of existing literature or in the development of estimates that impact our financial statements. These estimates and assumptions affect the reported amounts of assets and liabilities as of the date of the Condensed Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and assumptions, which are evaluated on a continual basis.
Revenue Recognition, Policy	We record revenues when services are provided to our distribution service customers. Revenues are recognized monthly on the accrual basis, which includes estimated amounts for gas delivered to customers but not yet billed under the cycle-billing method from the last meter reading date to month end.
Segment Reporting, Policy	Effective with the consummation of the Acquisition, our reportable segments changed to one segment, Gas Utilities and Infrastructure, based on information used by the chief decision maker in allocating resources and evaluating performance. Gas Utilities and Infrastructure, includes local gas distribution as state regulated utilities, gas pipeline investments and other gas investments. We evaluate the performance of the gas distribution business, including the operations of merchandising and its related service work and home service agreements, based on segment income, which is defined as income from continuing operations. Although the state regulated operations of our Gas Utilities and Infrastructure segment are located in three states under the jurisdiction of individual state regulatory commissions, the operations are managed as one unit having similar economic and risk characteristics. The remainder of our operations are presented in Other, which is primarily composed of our equity method investment in SouthStar Energy Services, LLC prior to its October 3, 2016 sale, contributions to the Piedmont Natural Gas Foundation and certain Acquisition-related expenses.
Asset Retirement Obligations, Policy	We record an asset retirement obligation (ARO) when we have a legal obligation to incur retirement costs associated with the retirement of long-lived assets that result from the acquisition, construction, development and operation of the assets and the fair value of the obligation can be reasonable estimated.
Goodwill and Intangible Assets, Policy	We are required to perform an annual goodwill impairment test as of the same date each year. With the change in our year end as discussed in Note 1, we have changed the date of our annual impairment testing of goodwill from October 31 to August 31 to align with our parent, Duke Energy.
Impairment of Long-Lived Assets, Policy	On a quarterly basis, or when events or changes in circumstances indicate, we evaluate our investments in unconsolidated affiliates and long-lived assets for impairment.
Equity Method Investments, Policy	On a quarterly basis, or when events or changes in circumstances indicate, we evaluate our investments in unconsolidated affiliates and long-lived assets for impairment.
Derivatives, Policy	We evaluate all of our gas supply contracts at inception to determine if they meet the definition of a derivative in accordance with accounting guidance, whether any derivative contracts qualify as "normal purchases and normal sales" and would not be subject to fair value accounting requirements, or if they can be designated for hedge accounting purposes. We have included gas supply contracts requiring fair value accounting in "Other" in "Current Liabilities" and "Deferred Credits and Other Liabilities" in the Condensed Consolidated Balance Sheets. As these contracts have been entered into for our regulated utility operations, and as commodity costs are recoverable through our PGA clauses in the jurisdictions in which we operate, we have recorded the offset to an applicable regulatory asset.
Income Tax, Policy	We and our wholly owned subsidiaries will be included in the Duke Energy consolidated income tax returns for the period October 4, 2016 through December 31, 2016. Piedmont and each of our subsidiaries have entered into a tax sharing agreement with Duke Energy and subsidiaries. The tax sharing agreement provides allocation of consolidated tax liabilities and benefits based on amounts participants would incur as separate C-Corporations.
Subsequent Events, Policy	We monitor significant events occurring after the balance sheet date and prior to the issuance of the financial statements to determine the impacts, if any, of events on the financial statements to be issued.

Summary Of Significant Accounting Policies (Policies)

2 Months Ended

Dec. 31, 2016

The Condensed Consolidated Financial Statements have not been audited. We have prepared the unaudited Condensed Consolidated Financial Statements under the rules of the Securities and Exchange Commission (SEC). Therefore, certain financial information and note disclosures normally included in annual financial statements prepared in conformity with generally accepted accounting principles (GAAP) in the United States of America are omitted in this interim report under these SEC rules and regulations.

Consolidation, Policy

The Condensed Consolidated Financial Statements reflect the accounts of Piedmont and its wholly owned subsidiaries whose financial statements are prepared for the same reporting period as Piedmont using consistent accounting policies. Inter-company transactions have been eliminated in consolidation where appropriate; however, we have not eliminated inter-company profit on sales to affiliates and costs from affiliates in accordance with accounting regulations prescribed under rate-based regulation.

Investments in unconsolidated affiliates, or joint ventures, are accounted for under the equity method as we do not have controlling voting interests or otherwise exercise control over the management of such companies.

Use of Estimates, Policy

In accordance with GAAP, we make certain estimates and assumptions regarding reported amounts of assets, liabilities, revenues and expenses and the related disclosures, using historical experience and other assumptions that we believe are reasonable at the time. Our estimates may involve complex situations requiring a high degree of judgment in the application and interpretation of existing literature or in the development of estimates that impact our financial statements. These estimates and assumptions affect the reported amounts of assets and liabilities as of the date of the Condensed Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and assumptions, which are evaluated on a continual basis.

Revenue Recognition, Policy

We record revenues when services are provided to our distribution service customers. Revenues are recognized monthly on the accrual basis, which includes estimated amounts for gas delivered to customers but not yet billed under the cycle-billing method from the last meter reading date to month end.

Segment Reporting, Policy

Effective with the consummation of the Acquisition, our reportable segments changed to one segment, Gas Utilities and Infrastructure, based on information used by the chief decision maker in allocating resources and evaluating performance. Gas Utilities and Infrastructure, includes local gas distribution as state regulated utilities, gas pipeline investments and other gas investments. We evaluate the performance of the gas distribution business, including the operations of merchandising and its related service work and home service agreements, based on segment income, which is defined as income from continuing operations. Although the state regulated operations of our Gas Utilities and Infrastructure segment are located in three states under the jurisdiction of individual state regulatory commissions, the operations are managed as one unit having similar economic and risk characteristics.

The remainder of our operations are presented in Other, which is primarily composed of our equity method investment in SouthStar Energy Services, LLC prior to its October 3, 2016 sale, contributions to the Piedmont Natural Gas Foundation and certain Acquisition-related expenses.

Asset Retirement Obligations, Policy

We record an asset retirement obligation (ARO) when we have a legal obligation to incur retirement costs associated with the retirement of long-lived assets that result from the acquisition, construction, development and operation of the assets and the fair value of the obligation can be reasonable estimated.

Goodwill and Intangible Assets, Policy

We are required to perform an annual goodwill impairment test as of the same date each year. With the change in our year end as discussed in Note 1, we have changed the date of our annual impairment testing of goodwill from October 31 to August 31 to align with our parent, Duke Energy.

Impairment of Long-Lived Assets, Policy

On a quarterly basis, or when events or changes in circumstances indicate, we evaluate our investments in unconsolidated affiliates and long-lived assets for impairment.

Equity Method Investments, Policy

On a quarterly basis, or when events or changes in circumstances indicate, we evaluate our investments in unconsolidated affiliates and long-lived assets for impairment.

Derivatives, Policy

We evaluate all of our gas supply contracts at inception to determine if they meet the definition of a derivative in accordance with accounting guidance, whether any derivative contracts qualify as "normal purchases and normal sales" and would not be subject to fair value accounting requirements, or if they can be designated for hedge accounting purposes.

We have included gas supply contracts requiring fair value accounting in "Other" in "Current Liabilities" and "Deferred Credits and Other Liabilities" in the Condensed Consolidated Balance Sheets. As these contracts have been entered into for our regulated utility operations, and as commodity costs are recoverable through our PGA clauses in the jurisdictions in which we operate, we have recorded the offset to an applicable regulatory asset.

Income Tax, Policy

We and our wholly owned subsidiaries will be included in the Duke Energy consolidated income tax returns for the period October 4, 2016 through December 31, 2016. Piedmont and each of our subsidiaries have entered into a tax sharing agreement with Duke Energy and subsidiaries. The tax sharing agreement provides allocation of consolidated tax liabilities and benefits based on amounts participants would incur as separate C-Corporations.

Subsequent Events, Policy

We monitor significant events occurring after the balance sheet date and prior to the issuance of the financial statements to determine the impacts, if any, of events on the financial statements to be issued.