| Cover | May 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 10, 2022 |
| Entity File Number | 1-6196 |
| Entity Registrant Name | PIEDMONT NATURAL GAS COMPANY, INC. |
| Entity Central Index Key | 0000078460 |
| Entity Tax Identification Number | 56-0556998 |
| Entity Incorporation, State or Country Code | NC |
| Entity Address, Address Line One | 4720 Piedmont Row Drive |
| Entity Address, City or Town | Charlotte |
| Entity Address, State or Province | NC |
| Entity Address, Postal Zip Code | 28210 |
| City Area Code | 704 |
| Local Phone Number | 364-3120 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
