Leases (Operating Lease Maturities) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 279
2021	239
2022	199
2023	190
2024	178
Thereafter	1,055
Total operating lease payments	2,140
Less: present value discount	(425)
Total operating lease liabilities	1,715
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	33
2021	28
2022	19
2023	18
2024	15
Thereafter	61
Total operating lease payments	174
Less: present value discount	(30)
Total operating lease liabilities	144
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	129
2021	112
2022	94
2023	95
2024	96
Thereafter	513
Total operating lease payments	1,039
Less: present value discount	(192)
Total operating lease liabilities	847
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	51
2021	52
2022	40
2023	40
2024	41
Thereafter	306
Total operating lease payments	530
Less: present value discount	(117)
Total operating lease liabilities	413
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	78
2021	60
2022	54
2023	55
2024	55
Thereafter	207
Total operating lease payments	509
Less: present value discount	(75)
Total operating lease liabilities	434
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	2
2021	2
2022	2
2023	2
2024	2
Thereafter	22
Total operating lease payments	32
Less: present value discount	(10)
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 [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	6
2021	5
2022	4
2023	4
2024	4
Thereafter	65
Total operating lease payments	88
Less: present value discount	(28)
Total operating lease liabilities	60
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 Natural Gas [Member]
Operating Lease Liabilities, Payments Due (Topic 842)
2020	5
2021	5
2022	5
2023	5
2024	5
Thereafter	7
Total operating lease payments	32
Less: present value discount	(3)
Total operating lease liabilities	$ 29
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