Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 951	$ 961
Other noncurrent assets	3,686	3,601
Total Assets	167,007	162,388
Other current liabilities	2,239	2,936
Other, noncurrent liabilities	1,714	1,719
VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	480	530
Other noncurrent assets		31
Deferred tax asset	58
Total Assets	538	561
Other current liabilities	64	933
Other, noncurrent liabilities	66	18
Total liabilities	130	951
Net assets	408	(390)
Duke Energy Ohio
Variable Interest Entities [Line Items]
Other noncurrent assets	83	72
Total Assets	10,505	10,025
Other current liabilities	68	70
Other, noncurrent liabilities	92	99
Duke Energy Ohio | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	47	83
Total Assets	47	83
Net assets	47	83
Duke Energy Indiana
Variable Interest Entities [Line Items]
Other noncurrent assets	276	253
Total Assets	14,428	14,041
Other current liabilities	104	83
Other, noncurrent liabilities	53	30
Duke Energy Indiana | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	77	110
Total Assets	77	110
Net assets	77	110
Pipeline Investments | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	15
Other noncurrent assets		31
Deferred tax asset	58
Total Assets	73	31
Other current liabilities	61	928
Other, noncurrent liabilities	63	8
Total liabilities	124	936
Net assets	(51)	(905)
Commercial Renewables | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	465	530
Total Assets	465	530
Other current liabilities	3	5
Other, noncurrent liabilities	3	10
Total liabilities	6	15
Net assets	$ 459	$ 515