Stock-Based Compensation (Schedule of Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	$ 65	$ 56	$ 43
Pretax stock-based compensation cost	89	78	68
Stock-based compensation costs capitalized	5	5	4
Stock-based compensation expense	84	73	64
Tax benefit associated with stock-based compensation expense	19	17	25
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	44	43	41
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pretax stock-based compensation cost	45	35	27
Duke Energy Carolinas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	24	20	15
Progress Energy
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	24	21	16
Duke Energy Progress
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	15	13	10
Duke Energy Florida
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	9	8	6
Duke Energy Ohio
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	5	4	3
Duke Energy Indiana
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expense recognized	6	5	4
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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