Employee Benefit Plans (Fair Value Measurements of Plan Assets - Master Retirement Trust) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ 95		$ 11
Master Trust
Defined Benefit Plan Disclosure [Line Items]
Total assets	9,352	$ 9,479
Master Trust | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	2,975	3,541
Master Trust | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	6,038	5,603
Master Trust | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	95
Master Trust | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	244	335
Master Trust | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	2,575	3,202
Master Trust | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	2,547	3,162
Master Trust | Equity securities | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	28	40
Master Trust | Corporate debt securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	4,189	4,162
Master Trust | Corporate debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	4,189	4,162
Master Trust | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Total assets	382	397
Master Trust | Short-term investment funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	272	247
Master Trust | Short-term investment funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	110	150
Master Trust | Partnership interests
Defined Benefit Plan Disclosure [Line Items]
Total assets	95	97
Master Trust | Partnership interests | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total assets	95
Master Trust | Partnership interests | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets		97
Master Trust | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total assets	216	198
Master Trust | Hedge funds | Not Categorized
Defined Benefit Plan Disclosure [Line Items]
Total assets	216	198
Master Trust | U.S. government bonds
Defined Benefit Plan Disclosure [Line Items]
Total assets	1,618	1,164
Master Trust | U.S. government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	1,618	1,164
Master Trust | Governments bonds – foreign
Defined Benefit Plan Disclosure [Line Items]
Total assets	78	73
Master Trust | Governments bonds – foreign | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	78	73
Master Trust | Cash
Defined Benefit Plan Disclosure [Line Items]
Total assets	144	98
Master Trust | Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	144	98
Master Trust | Government and commercial mortgage backed securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	2
Master Trust | Government and commercial mortgage backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	2
Master Trust | Net pending transactions and other investments
Defined Benefit Plan Disclosure [Line Items]
Total assets	53	88
Master Trust | Net pending transactions and other investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total assets	12	34
Master Trust | Net pending transactions and other investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	41	54
OPEB
Defined Benefit Plan Disclosure [Line Items]
Total assets	45	48
OPEB | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	45	48
OPEB | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	18	23
OPEB | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	18	23
OPEB | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total assets	2	1
OPEB | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	2	1
OPEB | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total assets	14	5
OPEB | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	14	5
OPEB | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	11	19
OPEB | Debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ 11	$ 19
Duke Energy Carolinas | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	26.00%	26.00%
Progress Energy | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	32.00%	32.00%
Duke Energy Progress | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	15.00%	15.00%
Duke Energy Florida | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	17.00%	17.00%
Duke Energy Ohio | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	5.00%	5.00%
Duke Energy Indiana | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	7.00%	7.00%
Piedmont | Master Trust
Defined Benefit Plan Disclosure [Line Items]
Allocated assets (as a percent)	4.00%	4.00%