Regulatory Matters (Regulatory Matters Narrative - Duke Energy Indiana) (Details) - USD ($) $ in Millions					3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Jul. 28, 2021	Jun. 29, 2020	Dec. 04, 2019	Jul. 02, 2019	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Sep. 20, 2023	Jun. 30, 2023	Feb. 03, 2023	Jun. 15, 2022	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges					$ 88	$ (4)		$ 96	$ 202
Operating Revenues					7,994	7,842		21,848	21,417
Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges									211
Operating Revenues					$ 851	$ 1,095		$ 2,606	$ 2,835
Indiana Coal Ash Recovery | IURC | Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Impairment of assets and other charges										$ 175
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
Indiana rate case 2019 | IURC | Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Estimated percentage of total rate increase, step one		75.00%
Requested rate increase (decrease), amount				$ 395
Requested rate increase, percentage, net of tax			15.60%
Requested rate increase (decrease), amended amount			$ 396
Approved rate increase (decrease), amount		$ 146
Rate base															$ 10,200
Reduction of requested rate increase		$ 200
Reduction due to depreciation methodology		50.00%
Reduction due to approved return on equity		20.00%
Approved return on equity percentage (as a percent)		9.70%
Requested return on equity (as a percent)		10.40%
Reduction due to earnings adjustments		20.00%
Estimated percentage of total rate increase, step two	25.00%
Impairment of assets and other charges							$ 211
Operating Revenues							$ 46
Regulatory Matters, Settlement To Customers												$ 70	$ 70