Regulatory Matters (Schedule of Net Carrying Value Of Facilities) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) MW	Dec. 31, 2018 USD ($)
Public Utilities, General Disclosures [Line Items]
Remaining net book value	$ 102,127	$ 91,694
Piedmont
Public Utilities, General Disclosures [Line Items]
Remaining net book value	6,765	5,911
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Remaining net book value	32,397	29,245
Duke Energy Indiana
Public Utilities, General Disclosures [Line Items]
Remaining net book value	$ 11,072	$ 10,529
Generating facilities planned for retirement
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	5,002
Remaining net book value	$ 2,937
Generating facilities planned for retirement | Duke Energy Carolinas | Allen Steam Station Units 1-3
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	585
Remaining net book value	$ 152
Generating facilities planned for retirement | Duke Energy Indiana | Gallagher Units 2 and 4
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	280
Remaining net book value	$ 114
Generating facilities planned for retirement | Duke Energy Indiana | Gibson Units 1 - 5
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	3,132
Remaining net book value	$ 1,697
Generating facilities planned for retirement | Duke Energy Indiana | Cayuga Units 1 - 2
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW	1,005
Remaining net book value	$ 974