Leases (Operating Lease Maturities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due (Topic 842)
2020	$ 271
2021	238
2022	192
2023	180
2024	169
Thereafter	1,057
Total operating lease payments	2,107
Less: present value discount	(436)
Total operating lease liabilities	1,671
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	32
2021	29
2022	19
2023	19
2024	16
Thereafter	66
Total operating lease payments	181
Less: present value discount	(32)
Total operating lease liabilities	149
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	125
2021	112
2022	90
2023	89
2024	89
Thereafter	530
Total operating lease payments	1,035
Less: present value discount	(198)
Total operating lease liabilities	837
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	47
2021	46
2022	35
2023	34
2024	35
Thereafter	309
Total operating lease payments	506
Less: present value discount	(118)
Total operating lease liabilities	388
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	66
2022	55
2023	55
2024	54
Thereafter	221
Total operating lease payments	529
Less: present value discount	(80)
Total operating lease liabilities	449
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	67
Total operating lease payments	90
Less: present value discount	(29)
Total operating lease liabilities	61
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	9
Total operating lease payments	34
Less: present value discount	(4)
Total operating lease liabilities	$ 30
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