Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	$ 924	$ 1,936
Total Assets	161,409	158,838
Taxes accrued	768	392
Current Liabilities: Other	2,829	2,367
Deferred income taxes	9,170	8,878
Other Noncurrent Liabilities: Other	1,773	1,581
VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	(1)	(1)
Other current assets	413
Investments in equity method unconsolidated affiliates	488	1,479
Deferred tax asset	26
Total Assets	926	1,478
Taxes accrued		(1)
Current Liabilities: Other	930	4
Deferred income taxes		59
Other Noncurrent Liabilities: Other	29	11
Total liabilities	959	73
Net assets	(33)	1,405
Duke Energy Ohio
Variable Interest Entities [Line Items]
Total Assets	9,749	9,338
Taxes accrued	193	219
Current Liabilities: Other	73	75
Deferred income taxes	965	922
Other Noncurrent Liabilities: Other	100	94
Duke Energy Ohio | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	45	64
Total Assets	45	64
Net assets	45	64
Duke Energy Indiana
Variable Interest Entities [Line Items]
Total Assets	13,914	13,276
Taxes accrued	110	49
Current Liabilities: Other	98	112
Deferred income taxes	1,179	1,150
Other Noncurrent Liabilities: Other	56	18
Duke Energy Indiana | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Receivables from affiliated companies	74	77
Total Assets	74	77
Net assets	74	77
Pipeline Investments | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Other current assets	413
Investments in equity method unconsolidated affiliates		1,179
Deferred tax asset	26
Total Assets	439	1,179
Taxes accrued		(1)
Current Liabilities: Other	927
Deferred income taxes		59
Other Noncurrent Liabilities: Other	19
Total liabilities	946	58
Net assets	(507)	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	487	300
Total Assets	486	299
Net assets	486	299
Other VIEs | VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in equity method unconsolidated affiliates	1
Total Assets	1
Current Liabilities: Other	3	4
Other Noncurrent Liabilities: Other	10	11
Total liabilities	13	15
Net assets	$ (12)	$ (15)