Regulatory Matters (Schedule of Net Carrying Value Of Facilities and Megawatt Capacity) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($) MW	Dec. 31, 2018 USD ($)
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 98,912	$ 91,694
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	31,456	29,245
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net	$ 10,937	$ 10,529
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	5,002
Public utilities, property, plant and equipment, net	$ 3,193
Allen Steam Station Units 1-3 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Public utilities, property, plant and equipment, net	$ 154
Gallagher Units 2 and 4 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Public utilities, property, plant and equipment, net	$ 116
Gibson Units 1-5 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	3,132
Public utilities, property, plant and equipment, net	$ 1,949
Cayuga Units 1-2 [Member] | Generation Facilities To Be Retired [Member] | Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,005
Public utilities, property, plant and equipment, net	$ 974