Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Total ARO	$ 12,601	$ 10,467
Less: current portion	861	919
Total noncurrent ARO	11,740	9,548
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,398	3,949
Less: current portion	214	290
Total noncurrent ARO	5,184	3,659
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,088	5,411
Less: current portion	478	514
Total noncurrent ARO	5,610	4,897
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,514	4,820
Less: current portion	476	509
Total noncurrent ARO	5,038	4,311
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	574	591
Less: current portion	2	5
Total noncurrent ARO	572	586
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	85	93
Less: current portion	3	6
Total noncurrent ARO	82	87
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	824	722
Less: current portion	165	109
Total noncurrent ARO	659	613
Piedmont Natural Gas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	20	19
Total noncurrent ARO	20	$ 19
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,789
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,435
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,295
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,769
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	526
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,486
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,917
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,722
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,707
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	15
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	43
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	804
Other [Member]
Asset Retirement Obligations [Line Items]
Total ARO	326
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	46
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	71
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	38
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	42
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	$ 20