Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 961	$ 1,936	$ 1,409
Other noncurrent assets	3,601	3,289
Total Assets	162,388	158,838	145,392
Other current liabilities	2,936	2,367
Deferred income taxes	9,244	8,878
Other Noncurrent Liabilities: Other	1,719	1,581
Non-consolidated VIEs
Variable Interest Entity [Line Items]
Receivables from affiliated companies		(1)
Investments in equity method unconsolidated affiliates	530	1,479
Other noncurrent assets	31
Total Assets	561	1,478
Taxes accrued		(1)
Other current liabilities	933	4
Deferred income taxes		59
Other Noncurrent Liabilities: Other	18	11
Total liabilities	951	73
Net assets (liabilities)	(390)	1,405
Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables from affiliated companies	102	92
Other noncurrent assets	72	52
Total Assets	10,025	9,338	$ 8,555
Other current liabilities	70	75
Deferred income taxes	981	922
Other Noncurrent Liabilities: Other	99	94
Duke Energy Ohio | Non-consolidated VIEs
Variable Interest Entity [Line Items]
Receivables from affiliated companies	83	64
Total Assets	83	64
Net assets (liabilities)	83	64
Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables from affiliated companies	112	79
Other noncurrent assets	253	234
Total Assets	14,041	13,276
Other current liabilities	83	112
Deferred income taxes	1,228	1,150
Other Noncurrent Liabilities: Other	30	18
Duke Energy Indiana | Non-consolidated VIEs
Variable Interest Entity [Line Items]
Receivables from affiliated companies	110	77
Total Assets	110	77
Net assets (liabilities)	110	77
Pipeline Investments | Non-consolidated VIEs
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates		1,179
Other noncurrent assets	31
Total Assets	31	1,179
Taxes accrued		(1)
Other current liabilities	928
Deferred income taxes		59
Other Noncurrent Liabilities: Other	8
Total liabilities	936	58
Net assets (liabilities)	(905)	1,121
Commercial Renewables | Non-consolidated VIEs
Variable Interest Entity [Line Items]
Receivables from affiliated companies		(1)
Investments in equity method unconsolidated affiliates	530	300
Total Assets	530	299
Other current liabilities	5	4
Other Noncurrent Liabilities: Other	10	11
Total liabilities	15	15
Net assets (liabilities)	$ 515	$ 284