Leases (Operating Lease Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 268
2021	216
2022	201
2023	191
2024	176
Thereafter	984
Total operating lease payments	2,036
Less: present value discount	(396)
Total operating lease liabilities	1,640
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		$ 239
2020		219
2021		186
2022		170
2023		160
Thereafter		1,017
Total		1,991
Duke Energy Carolinas
Operating Lease Liabilities, Payments Due (Topic 842)
2020	31
2021	19
2022	19
2023	17
2024	13
Thereafter	57
Total operating lease payments	156
Less: present value discount	(27)
Total operating lease liabilities	129
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		33
2020		29
2021		19
2022		19
2023		17
Thereafter		68
Total		185
Progress Energy
Operating Lease Liabilities, Payments Due (Topic 842)
2020	123
2021	99
2022	95
2023	95
2024	95
Thereafter	462
Total operating lease payments	969
Less: present value discount	(177)
Total operating lease liabilities	792
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		97
2020		90
2021		79
2022		76
2023		77
Thereafter		455
Total		874
Duke Energy Progress
Operating Lease Liabilities, Payments Due (Topic 842)
2020	51
2021	44
2022	40
2023	41
2024	41
Thereafter	283
Total operating lease payments	500
Less: present value discount	(109)
Total operating lease liabilities	391
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		49
2020		46
2021		37
2022		34
2023		35
Thereafter		314
Total		515
Duke Energy Florida
Operating Lease Liabilities, Payments Due (Topic 842)
2020	72
2021	55
2022	55
2023	54
2024	54
Thereafter	179
Total operating lease payments	469
Less: present value discount	(68)
Total operating lease liabilities	401
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		48
2020		44
2021		42
2022		42
2023		42
Thereafter		141
Total		359
Duke Energy Ohio
Operating Lease Liabilities, Payments Due (Topic 842)
2020	2
2021	2
2022	2
2023	2
2024	2
Thereafter	21
Total operating lease payments	31
Less: present value discount	(9)
Total operating lease liabilities	22
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		2
2020		2
2021		2
2022		2
2023		2
Thereafter		23
Total		33
Duke Energy Indiana
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	4
2022	4
2023	4
2024	4
Thereafter	64
Total operating lease payments	85
Less: present value discount	(27)
Total operating lease liabilities	58
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		6
2020		5
2021		4
2022		4
2023		5
Thereafter		66
Total		90
Piedmont
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	5
2022	5
2023	5
2024	5
Thereafter	5
Total operating lease payments	30
Less: present value discount	(3)
Total operating lease liabilities	$ 27
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (Topic 840)
2019		5
2020		5
2021		5
2022		5
2023		6
Thereafter		11
Total		$ 37