Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 1,936	$ 1,409	$ 1,175
Other Noncurrent Assets: Other	3,289	2,935
Current Liabilities: Other	2,367	2,085
Deferred income taxes	8,878	7,806
Other Noncurrent Liabilities: Other	1,581	1,650
Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables from affiliated companies	92	114
Other Noncurrent Assets: Other	52	41
Current Liabilities: Other	75	74
Deferred income taxes	922	817
Other Noncurrent Liabilities: Other	94	93
Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables from affiliated companies	79	122
Other Noncurrent Assets: Other	234	194
Current Liabilities: Other	112	107
Deferred income taxes	1,150	1,009
Other Noncurrent Liabilities: Other	18	16
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Receivables from affiliated companies	(1)
Investments in equity method unconsolidated affiliates	1,479	1,060
Total assets	1,478	1,060
Taxes accrued	(1)	(1)
Current Liabilities: Other	4	4
Deferred income taxes	59	21
Other Noncurrent Liabilities: Other	11	12
Total liabilities	73	36
Net assets (liabilities) of non-consolidated VIEs	1,405	1,024
VIE, Not Primary Beneficiary | Duke Energy Ohio
Variable Interest Entity [Line Items]
Receivables from affiliated companies	64	93
Total assets	64	93
Net assets (liabilities) of non-consolidated VIEs	64	93
VIE, Not Primary Beneficiary | Duke Energy Indiana
Variable Interest Entity [Line Items]
Receivables from affiliated companies	77	118
Total assets	77	118
Net assets (liabilities) of non-consolidated VIEs	77	118
VIE, Not Primary Beneficiary | Pipeline Investments
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	1,179	822
Total assets	1,179	822
Taxes accrued	(1)	(1)
Deferred income taxes	59	21
Total liabilities	58	20
Net assets (liabilities) of non-consolidated VIEs	1,121	802
VIE, Not Primary Beneficiary | Commercial Renewables
Variable Interest Entity [Line Items]
Receivables from affiliated companies	(1)
Investments in equity method unconsolidated affiliates	300	190
Total assets	299	190
Net assets (liabilities) of non-consolidated VIEs	299	190
VIE, Not Primary Beneficiary | Other VIEs
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates		48
Total assets		48
Current Liabilities: Other	4	4
Other Noncurrent Liabilities: Other	11	12
Total liabilities	15	16
Net assets (liabilities) of non-consolidated VIEs	(15)	$ 32
VIE, Not Primary Beneficiary | Pioneer
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 57
VIE Ownership interest	50.00%