Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Asset Retirement Obligations [Line Items]
Total ARO	$ 12,628	$ 10,467
Less: current portion	739	919
Total noncurrent ARO	11,889	9,548
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,342	3,949
Less: current portion	203	290
Total noncurrent ARO	5,139	3,659
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	6,193	5,411
Less: current portion	416	514
Total noncurrent ARO	5,777	4,897
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	5,616	4,820
Less: current portion	413	509
Total noncurrent ARO	5,203	4,311
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	577	591
Less: current portion	3	5
Total noncurrent ARO	574	586
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	89	93
Less: current portion	6	6
Total noncurrent ARO	83	87
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Total ARO	719	722
Less: current portion	115	109
Total noncurrent ARO	604	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	5,807
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,401
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	3,265
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,739
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	6,498
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,894
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,858
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Total ARO	2,839
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	19
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Total ARO	47
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	323
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	38
Other [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Total ARO	32
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	$ 19