Fair Value Measurements (Other Fair Value Disclosures) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 63,835	$ 59,863
Long-term debt, fair value	69,683	69,292
Unamortized debt discount and premium, net	1,250	1,300
Duke Energy Carolinas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	13,275	12,218
Long-term debt, fair value	15,101	14,917
Progress Energy
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	20,823	19,264
Long-term debt, fair value	23,751	23,470
Duke Energy Progress
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	10,249	9,258
Long-term debt, fair value	11,252	10,862
Duke Energy Florida
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	8,482	7,915
Long-term debt, fair value	9,772	9,756
Duke Energy Ohio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	3,193	3,089
Long-term debt, fair value	3,570	3,650
Duke Energy Indiana
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	4,323	4,091
Long-term debt, fair value	5,067	5,204
Piedmont
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	2,968	2,780
Long-term debt, fair value	$ 3,278	$ 3,306