Fair Value Measurements (Other Fair Value Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 66,080	$ 63,835
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	66,633	69,683
Piedmont Natural Gas and Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized debt discount (premium), net	1,200	1,250
Duke Energy Carolinas | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	14,470	13,275
Duke Energy Carolinas | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	15,117	15,101
Progress Energy | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	21,657	20,823
Progress Energy | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	22,669	23,751
Duke Energy Progress | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	11,114	10,249
Duke Energy Progress | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	11,260	11,252
Duke Energy Florida | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,451	8,482
Duke Energy Florida | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	8,911	9,772
Duke Energy Ohio | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,193	3,193
Duke Energy Ohio | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	3,278	3,570
Duke Energy Indiana | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,270	4,323
Duke Energy Indiana | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,554	5,067
Piedmont | Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,969	2,968
Piedmont | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 2,984	$ 3,278