Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 116
Due after one through five years	696
Due after five through 10 years	598
Due after 10 years	1,593
Total	3,003
Duke Energy Carolinas
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	9
Due after one through five years	226
Due after five through 10 years	333
Due after 10 years	870
Total	1,438
Progress Energy
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	89
Due after one through five years	391
Due after five through 10 years	217
Due after 10 years	620
Total	1,317
Duke Energy Progress
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	13
Due after one through five years	254
Due after five through 10 years	204
Due after 10 years	579
Total	1,050
Duke Energy Florida
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	76
Due after one through five years	137
Due after five through 10 years	13
Due after 10 years	41
Total	267
Duke Energy Indiana
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	7
Due after one through five years	20
Due after five through 10 years	11
Due after 10 years	26
Total	$ 64