Regulatory Matters (Regulatory Matters Narrative - Duke Energy Indiana) (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Apr. 04, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2026	Dec. 31, 2025	Sep. 20, 2023	Jun. 15, 2022
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges		$ 1	$ 8
Operating Revenues		7,671	7,276
Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Operating Revenues		$ 759	$ 975
Indiana Coal Ash Recovery | IURC | Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Interest rate on refunds (as a percent)						4.71%
TDSIG 2.0 | IURC | Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Future investment in infrastructure							$ 2,000
2024 Indiana Rate Case | IURC | Duke Energy Indiana | Subsequent event
Public Utilities, General Disclosures [Line Items]
Future investment in infrastructure	$ 1,600
Requested rate increase (decrease), amount	$ 492
Requested rate increase, percentage, net of tax	16.20%
Requested return on equity (as a percent)	10.50%
Equity ratio (as a percent)	53.00%
2024 Indiana Rate Case | IURC | Duke Energy Indiana | Forecast | Subsequent event
Public Utilities, General Disclosures [Line Items]
Requested rate increase, percentage, net of tax				4.50%	11.70%