Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	$ 61	$ 65	$ 56
Pretax stock-based compensation cost	84	89	78
Stock-based compensation costs capitalized	5	5	5
Stock-based compensation expense	79	84	73
Tax benefit associated with stock-based compensation expense	18	19	17
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	46	44	43
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	38	45	35
Duke Energy Carolinas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	22	24	20
Progress Energy
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	23	24	21
Duke Energy Progress
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	15	15	13
Duke Energy Florida
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	9	9	8
Duke Energy Ohio
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	4	5	4
Duke Energy Indiana
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	6	6	5
Piedmont
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	$ 3	$ 3	$ 3

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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