Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Derivatives (net)
Balance at beginning of period	$ 34	$ 24
Purchases, sales, issuances and settlements:
Settlements	(20)	(7)
Total losses included on the Condensed Consolidated Balance Sheet	(2)	(7)
Balance at end of period	12	10
Duke Energy Indiana
Derivatives (net)
Balance at beginning of period	29	22
Purchases, sales, issuances and settlements:
Settlements	(19)	(6)
Total losses included on the Condensed Consolidated Balance Sheet	1	(6)
Balance at end of period	$ 11	$ 10