Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 10,467	$ 10,175	$ 10,611
Asset Retirement Obligation, Current	919	689
Asset Retirement Obligations, Noncurrent	9,548	9,486
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,696
Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	4,446
Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	325
Duke Energy Carolinas [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,949	3,610	3,895
Asset Retirement Obligation, Current	290	337
Asset Retirement Obligations, Noncurrent	3,659	3,273
Duke Energy Carolinas [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,335
Duke Energy Carolinas [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	1,568
Duke Energy Carolinas [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	46
Progress Energy [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,411	5,414	5,475
Asset Retirement Obligation, Current	514	295
Asset Retirement Obligations, Noncurrent	4,897	5,119
Progress Energy [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,209
Progress Energy [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,123
Progress Energy [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	79
Duke Energy Progress [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	4,820	4,673	4,697
Asset Retirement Obligation, Current	509	295
Asset Retirement Obligations, Noncurrent	4,311	4,378
Duke Energy Progress [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,679
Duke Energy Progress [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,103
Duke Energy Progress [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	38
Duke Energy Florida [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	591	742	778
Asset Retirement Obligation, Current	5
Asset Retirement Obligations, Noncurrent	586	742
Duke Energy Florida [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	530
Duke Energy Florida [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	20
Duke Energy Florida [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	41
Duke Energy Ohio [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	93	84	77
Asset Retirement Obligation, Current	6	3
Asset Retirement Obligations, Noncurrent	87	81
Duke Energy Ohio [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	52
Duke Energy Ohio [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	41
Duke Energy Indiana [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	722	781	866
Asset Retirement Obligation, Current	109	54
Asset Retirement Obligations, Noncurrent	613	727
Duke Energy Indiana [Member] | Closure of Ash Impoundments [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	702
Duke Energy Indiana [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	20
Piedmont Natural Gas [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	19	15	$ 14
Asset Retirement Obligations, Noncurrent	19	$ 15
Piedmont Natural Gas [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 19