Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	$ 286	$ 125
Lease obligations	515	462
Pension, post-retirement and other employee benefits	236	303
Progress Energy merger purchase accounting adjustments	441	389
Tax credits and NOL carryforwards	3,909	3,925
Other	93	97
Valuation allowance	(586)	(587)
Total deferred income tax assets	4,894	4,714
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(2,267)	(1,664)
Accelerated depreciation rates	(10,729)	(10,813)
Regulatory assets and deferred debits, net	(1,142)	(1,115)
Total deferred income tax liabilities	(14,138)	(13,592)
Net deferred income tax liabilities	(9,244)	(8,878)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	3,909	3,925
Valuation allowance	586	587
General Business Credits
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	2,033
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	2,033
NOL Carryforwards | Federal
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	154
Valuation allowance	(4)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	154
Valuation allowance	4
NOL Carryforwards | State
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	340
Valuation allowance	(97)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	340
Valuation allowance	97
NOL Carryforwards | Foreign
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	12
Valuation allowance	(12)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	12
Valuation allowance	12
Capital loss carryforwards | Federal
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	85
Valuation allowance	(85)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	85
Valuation allowance	85
Foreign Tax Credit
Deferred Tax Assets, Gross [Abstract]
Valuation allowance	(388)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Valuation allowance	388
Foreign Tax Credit | Foreign
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	1,272
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	1,272
Charitable contribution carryforwards
Deferred Tax Assets, Gross [Abstract]
Tax credits and NOL carryforwards	13
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	13
Duke Energy Carolinas
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	85	24
Lease obligations	96	72
Pension, post-retirement and other employee benefits	(30)	(5)
Tax credits and NOL carryforwards	285	262
Regulatory liabilities and deferred credits	11
Other	8	5
Total deferred income tax assets	455	358
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(1,127)	(981)
Accelerated depreciation rates	(3,170)	(3,254)
Regulatory assets and deferred debits, net		(44)
Total deferred income tax liabilities	(4,297)	(4,279)
Net deferred income tax liabilities	(3,842)	(3,921)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	285	262
Progress Energy
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	87	25
Lease obligations	208	193
Pension, post-retirement and other employee benefits	68	88
Tax credits and NOL carryforwards	508	486
Other	14	8
Total deferred income tax assets	885	800
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(669)	(577)
Accelerated depreciation rates	(3,868)	(3,798)
Regulatory assets and deferred debits, net	(744)	(887)
Total deferred income tax liabilities	(5,281)	(5,262)
Net deferred income tax liabilities	(4,396)	(4,462)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	508	486
Duke Energy Progress
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	67	49
Lease obligations	120	92
Pension, post-retirement and other employee benefits	24	38
Tax credits and NOL carryforwards	179	176
Other	9	3
Total deferred income tax assets	399	358
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(507)	(390)
Accelerated depreciation rates	(1,778)	(1,918)
Regulatory assets and deferred debits, net	(412)	(438)
Total deferred income tax liabilities	(2,697)	(2,746)
Net deferred income tax liabilities	(2,298)	(2,388)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	179	176
Duke Energy Florida
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	18
Lease obligations	87	102
Pension, post-retirement and other employee benefits	38	44
Tax credits and NOL carryforwards	282	253
Other	4	2
Total deferred income tax assets	429	401
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(164)	(190)
Accelerated depreciation rates	(2,124)	(1,913)
Regulatory assets and deferred debits, net	(332)	(477)
Total deferred income tax liabilities	(2,620)	(2,580)
Net deferred income tax liabilities	(2,191)	(2,179)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	282	253
Duke Energy Ohio
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	21	14
Lease obligations	5	5
Pension, post-retirement and other employee benefits	16	17
Tax credits and NOL carryforwards	16	16
Regulatory liabilities and deferred credits	18	36
Investments and other assets	7	10
Other	7	8
Total deferred income tax assets	90	106
Deferred Tax Liabilities, Gross [Abstract]
Accelerated depreciation rates	(1,071)	(1,028)
Total deferred income tax liabilities	(1,071)	(1,028)
Net deferred income tax liabilities	(981)	(922)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	16	16
Duke Energy Indiana
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	7	5
Lease obligations	16	17
Pension, post-retirement and other employee benefits	26	27
Tax credits and NOL carryforwards	183	176
Regulatory liabilities and deferred credits	0	52
Investments and other assets
Other	1	1
Total deferred income tax assets	233	278
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(14)	(12)
Accelerated depreciation rates	(1,433)	(1,416)
Regulatory assets and deferred debits, net	(14)
Total deferred income tax liabilities	(1,461)	(1,428)
Net deferred income tax liabilities	(1,228)	(1,150)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	183	176
Piedmont
Deferred Tax Assets, Gross [Abstract]
Deferred credits and other liabilities	38	22
Lease obligations	5	6
Pension, post-retirement and other employee benefits	(5)	(3)
Tax credits and NOL carryforwards	29	19
Regulatory liabilities and deferred credits		42
Investments and other assets		2
Other	8	6
Total deferred income tax assets	75	94
Deferred Tax Liabilities, Gross [Abstract]
Investments and other assets	(48)
Accelerated depreciation rates	(844)	(802)
Regulatory assets and deferred debits, net	(4)
Total deferred income tax liabilities	(896)	(802)
Net deferred income tax liabilities	(821)	(708)
Components and Expiration Dates of Tax Credits and NOL Carryforwards [Abstract]
Tax credits and NOL carryforwards	$ 29	$ 19