Regulatory Matters (Regulatory Matters Narrative - Duke Energy Carolinas) (Details) - USD ($) $ in Millions			3 Months Ended		4 Months Ended	9 Months Ended		12 Months Ended
	Aug. 22, 2023	Jan. 19, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2026	Sep. 30, 2023	Sep. 30, 2022	Aug. 31, 2026	Aug. 31, 2025	Aug. 31, 2024
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges			$ 88	$ (4)		$ 96	$ 202
Operation, maintenance and other			1,428	1,308		4,113	4,223
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges			64	6		70	(3)
Operation, maintenance and other			$ 424	$ 436		1,285	$ 1,410
2023 North Carolina Rate Case | NCUC | Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Proposed rate period (in years)		3 years
Settlement rate, amount	$ 19,500
Settlement rate, period (in years)	3 years
Impairment of assets and other charges						59
Operation, maintenance and other						$ 8
2023 North Carolina Rate Case | NCUC | Duke Energy Carolinas | Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					$ 823			$ 150	$ 172
Requested rate increase (decrease) (as a percent)					15.70%
2023 North Carolina Rate Case | NCUC | Duke Energy Carolinas | Forecast | Subsequent event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount										$ 501
2023 North Carolina Rate Case, Retail Allocated | NCUC | Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Settlement rate, amount	$ 4,600