Employee Benefit Plans (Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Pension Plan \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	$ 667
2022	650
2023	655
2024	644
2025	617
2026-2030	2,745
Pension Plan \| Duke Energy Carolinas \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	169
2022	170
2023	174
2024	168
2025	163
2026-2030	677
Pension Plan \| Progress Energy \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	177
2022	176
2023	181
2024	184
2025	181
2026-2030	846
Pension Plan \| Duke Energy Progress \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	94
2022	92
2023	95
2024	96
2025	93
2026-2030	399
Pension Plan \| Duke Energy Florida \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	82
2022	83
2023	85
2024	87
2025	88
2026-2030	443
Pension Plan \| Duke Energy Ohio \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	40
2022	39
2023	38
2024	37
2025	35
2026-2030	154
Pension Plan \| Duke Energy Indiana \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	53
2022	51
2023	49
2024	49
2025	47
2026-2030	217
Pension Plan \| Piedmont \| Qualified Plan
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	29
2022	25
2023	22
2024	21
2025	19
2026-2030	83
Other Post-Retirement Benefit Plans
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	73
2022	66
2023	62
2024	58
2025	54
2026-2030	223
Other Post-Retirement Benefit Plans \| Duke Energy Carolinas
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	17
2022	16
2023	15
2024	14
2025	13
2026-2030	54
Other Post-Retirement Benefit Plans \| Progress Energy
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	28
2022	26
2023	25
2024	24
2025	22
2026-2030	94
Other Post-Retirement Benefit Plans \| Duke Energy Progress
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	15
2022	14
2023	14
2024	13
2025	12
2026-2030	52
Other Post-Retirement Benefit Plans \| Duke Energy Florida
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	12
2022	12
2023	11
2024	11
2025	10
2026-2030	41
Other Post-Retirement Benefit Plans \| Duke Energy Ohio
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	3
2022	3
2023	3
2024	2
2025	2
2026-2030	9
Other Post-Retirement Benefit Plans \| Duke Energy Indiana
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	8
2022	7
2023	6
2024	6
2025	5
2026-2030	21
Other Post-Retirement Benefit Plans \| Piedmont
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	2
2022	2
2023	2
2024	2
2025	2
2026-2030	$ 11

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Amount of benefit for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following current fiscal year.

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