Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Total ARO	$ 13,035	$ 10,467
Less: current portion	779	919
Total noncurrent ARO	12,256	9,548
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,428	3,949
Less: current portion	209	290
Total noncurrent ARO	5,219	3,659
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,506	5,411
Less: current portion	456	514
Total noncurrent ARO	6,050	4,897
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,923	4,820
Less: current portion	452	509
Total noncurrent ARO	5,471	4,311
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	583	591
Less: current portion	4	5
Total noncurrent ARO	579	586
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	93	93
Less: current portion	6	6
Total noncurrent ARO	87	87
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	719	722
Less: current portion	108	109
Total noncurrent ARO	611	613
Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	19	19
Total noncurrent ARO	19	$ 19
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,753
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,368
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,239
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,709
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	530
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,961
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,013
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,197
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,177
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	52
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	699
Other [Member]
Asset Retirement Obligations [Line Items]
Total ARO	321
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	47
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	70
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	37
Other [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	33
Other [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	41
Other [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20
Other [Member] | Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	$ 19