Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 2,067	$ 1,936
Taxes accrued	493	392
Current Liabilities: Other	2,004	2,367
Deferred income taxes	9,321	8,878
Other Noncurrent Liabilities: Other	1,669	1,581
VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	(1)	(1)
Investments in equity method unconsolidated affiliates	1,614	1,479
Total assets	1,613	1,478
Taxes accrued	(1)	(1)
Current Liabilities: Other	3	4
Deferred income taxes	69	59
Other Noncurrent Liabilities: Other	116	11
Total liabilities	187	73
Net assets	1,426	1,405
Pipeline Investments | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1,243	1,179
Total assets	1,243	1,179
Taxes accrued	(1)	(1)
Deferred income taxes	69	59
Other Noncurrent Liabilities: Other	105
Total liabilities	173	58
Net assets	1,070	1,121
Commercial Renewables | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	(1)	(1)
Investments in equity method unconsolidated affiliates	371	300
Total assets	370	299
Net assets	370	299
Other VIEs | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Current Liabilities: Other	3	4
Other Noncurrent Liabilities: Other	11	11
Total liabilities	14	15
Net assets	(14)	(15)
Duke Energy Ohio
Variable Interest Entities [Line Items]
Receivables from affiliated companies	52	92
Taxes accrued	170	219
Current Liabilities: Other	68	75
Deferred income taxes	942	922
Other Noncurrent Liabilities: Other	97	94
Duke Energy Ohio | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	39	64
Total assets	39	64
Net assets	39	64
Duke Energy Indiana
Variable Interest Entities [Line Items]
Receivables from affiliated companies	76	79
Taxes accrued	81	49
Current Liabilities: Other	92	112
Deferred income taxes	1,158	1,150
Other Noncurrent Liabilities: Other	30	18
Duke Energy Indiana | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	48	77
Total assets	48	77
Net assets	$ 48	$ 77