Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 938	$ 961
Other noncurrent assets	3,652	3,601
Total Assets	165,385	162,388
Other current liabilities	1,994	2,936
Other, noncurrent liabilities	1,809	1,719
VIE not primary beneficiary
Variable Interest Entities [Line Items]
Other current assets	17
Investments in equity method unconsolidated affiliates	490	530
Other noncurrent assets		31
Deferred tax asset	19
Total Assets	526	561
Other current liabilities	37	933
Other, noncurrent liabilities	79	18
Total liabilities	116	951
Net assets	410	(390)
Duke Energy Ohio
Variable Interest Entities [Line Items]
Other noncurrent assets	79	72
Total Assets	10,322	10,025
Other current liabilities	70	70
Other, noncurrent liabilities	96	99
Duke Energy Ohio | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	54	83
Total Assets	54	83
Net assets	54	83
Duke Energy Indiana
Variable Interest Entities [Line Items]
Other noncurrent assets	268	253
Total Assets	14,155	14,041
Other current liabilities	104	83
Other, noncurrent liabilities	32	30
Duke Energy Indiana | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	85	110
Total Assets	85	110
Net assets	85	110
Pipeline Investments | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Other current assets	17
Investments in equity method unconsolidated affiliates	15
Other noncurrent assets		31
Deferred tax asset	19
Total Assets	51	31
Other current liabilities	33	928
Other, noncurrent liabilities	69	8
Total liabilities	102	936
Net assets	(51)	(905)
Commercial Renewables | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	475	530
Total Assets	475	530
Other current liabilities	4	5
Other, noncurrent liabilities	10	10
Total liabilities	14	15
Net assets	$ 461	$ 515