Debt and Credit Facilities (Narrative) (Details) - Master Credit Facility	Mar. 31, 2020 USD ($)
Debt Instrument [Line Items]
Facility size	$ 8,000,000,000
Duke Energy Carolinas
Debt Instrument [Line Items]
Facility size	1,500,000,000
Duke Energy Carolinas \| USDOJ \| North Carolina ash basins
Debt Instrument [Line Items]
Minimum master credit facility balance required	$ 250,000,000

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant