Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Sep. 30, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 139
Due after one through five years	854
Due after five through 10 years	451
Due after 10 years	1,376
Total	2,820
Duke Energy Carolinas
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	7
Due after one through five years	301
Due after five through 10 years	208
Due after 10 years	770
Total	1,286
Progress Energy
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	115
Due after one through five years	473
Due after five through 10 years	191
Due after 10 years	516
Total	1,295
Duke Energy Progress
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	35
Due after one through five years	259
Due after five through 10 years	176
Due after 10 years	481
Total	951
Duke Energy Florida
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	80
Due after one through five years	214
Due after five through 10 years	15
Due after 10 years	35
Total	344
Duke Energy Indiana
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	8
Due after one through five years	22
Due after five through 10 years	7
Due after 10 years	22
Total	$ 59