Leases (Finance Lease Maturities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	$ 179
2021	184
2022	177
2023	173
2024	149
Thereafter	827
Total finance lease payments	1,689
Less: amounts representing interest	(699)
Total finance lease liabilities	990
Finance Lease Liabilities, Payments Due (Topic 840)
2019		$ 170
2020		174
2021		177
2022		165
2023		165
Thereafter		577
Minimum annual payments		1,428
Less: amount representing interest		(487)
Total		941
Duke Energy Carolinas [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	19
2021	16
2022	14
2023	14
2024	14
Thereafter	189
Total finance lease payments	266
Less: amounts representing interest	(160)
Total finance lease liabilities	106
Finance Lease Liabilities, Payments Due (Topic 840)
2019		20
2020		20
2021		15
2022		15
2023		15
Thereafter		204
Minimum annual payments		289
Less: amount representing interest		(180)
Total		109
Progress Energy [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	69
2021	69
2022	69
2023	69
2024	57
Thereafter	552
Total finance lease payments	885
Less: amounts representing interest	(477)
Total finance lease liabilities	408
Finance Lease Liabilities, Payments Due (Topic 840)
2019		45
2020		46
2021		45
2022		45
2023		45
Thereafter		230
Minimum annual payments		456
Less: amount representing interest		(205)
Total		251
Duke Energy Progress [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	44
2021	44
2022	44
2023	44
2024	44
Thereafter	539
Total finance lease payments	759
Less: amounts representing interest	(451)
Total finance lease liabilities	308
Finance Lease Liabilities, Payments Due (Topic 840)
2019		20
2020		21
2021		20
2022		21
2023		21
Thereafter		209
Minimum annual payments		312
Less: amount representing interest		(175)
Total		137
Duke Energy Florida [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	25
2021	25
2022	25
2023	25
2024	13
Thereafter	13
Total finance lease payments	126
Less: amounts representing interest	(26)
Total finance lease liabilities	100
Finance Lease Liabilities, Payments Due (Topic 840)
2019		25
2020		25
2021		25
2022		24
2023		24
Thereafter		21
Minimum annual payments		144
Less: amount representing interest		(30)
Total		114
Duke Energy Ohio [Member]
Finance Lease Liabilities, Payments Due (Topic 840)
2019		2
Minimum annual payments		2
Total		2
Duke Energy Indiana [Member]
Finance Lease Liabilities, Payments, Due (Topic 842)
2020	1
2021	1
2022	1
2023	1
2024	1
Thereafter	27
Total finance lease payments	32
Less: amounts representing interest	(22)
Total finance lease liabilities	$ 10
Finance Lease Liabilities, Payments Due (Topic 840)
2019		1
2020		1
2021		1
2022		1
2023		1
Thereafter		27
Minimum annual payments		32
Less: amount representing interest		(22)
Total		$ 10