Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Jun. 30, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 142
Due after one through five years	699
Due after five through 10 years	550
Due after 10 years	1,467
Total	2,858
Duke Energy Carolinas
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	7
Due after one through five years	227
Due after five through 10 years	298
Due after 10 years	802
Total	1,334
Progress Energy
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	121
Due after one through five years	394
Due after five through 10 years	208
Due after 10 years	561
Total	1,284
Duke Energy Progress
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	25
Due after one through five years	225
Due after five through 10 years	194
Due after 10 years	524
Total	968
Duke Energy Florida
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	96
Due after one through five years	169
Due after five through 10 years	14
Due after 10 years	37
Total	316
Duke Energy Indiana
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	5
Due after one through five years	22
Due after five through 10 years	11
Due after 10 years	24
Total	$ 62