Investments in Debt and Equity Securities (Maturities) (Details) $ in Millions	Mar. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	$ 115
Due after one through five years	793
Due after five through 10 years	522
Due after 10 years	1,443
Total	2,873
Duke Energy Carolinas
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	5
Due after one through five years	277
Due after five through 10 years	262
Due after 10 years	785
Total	1,329
Progress Energy
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	96
Due after one through five years	424
Due after five through 10 years	207
Due after 10 years	564
Total	1,291
Duke Energy Progress
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	19
Due after one through five years	238
Due after five through 10 years	194
Due after 10 years	526
Total	977
Duke Energy Florida
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	77
Due after one through five years	186
Due after five through 10 years	13
Due after 10 years	38
Total	314
Duke Energy Indiana
Debt Securities, Available-for-sale [Line Items]
Due in one year or less	6
Due after one through five years	23
Due after five through 10 years	11
Due after 10 years	24
Total	$ 64