Variable Interest Entities (Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Regulatory Assets: Current	$ 1,641	$ 1,796
Current Assets: Other	462	764
Property, Plant and Equipment: Cost	155,580	147,654
Accumulated depreciation and amortization	(48,827)	(45,773)
Other Noncurrent Assets: Other	3,601	3,289
Other Noncurrent Assets: Regulatory assets	12,421	13,222
Current Liabilities: Other	2,936	2,367
Current maturities of long-term debt	4,238	3,141
Long-Term Debt	55,625	54,985
Asset retirement obligations	12,286	12,437
Other Noncurrent Liabilities: Other	1,719	1,581
Duke Energy Florida
Variable Interest Entity [Line Items]
Regulatory Assets: Current	265	419
Current Assets: Other	41	58
Property, Plant and Equipment: Cost	22,123	20,457
Accumulated depreciation and amortization	(5,560)	(5,236)
Other Noncurrent Assets: Other	335	311
Other Noncurrent Assets: Regulatory assets	1,799	2,194
Current Liabilities: Other	374	415
Current maturities of long-term debt	823	571
Long-Term Debt	7,092	7,416
Asset retirement obligations	514	578
Other Noncurrent Liabilities: Other	209	136
DEFPF | Duke Energy Florida | Consolidated VIEs
Variable Interest Entity [Line Items]
Receivables of VIEs	4	5
Regulatory Assets: Current	53	52
Current Assets: Other	39	39
Other Noncurrent Assets: Regulatory assets	937	989
Current Liabilities: Other	10	10
Current maturities of long-term debt	55	54
Long-Term Debt	1,002	1,057
Commercial Renewables | Consolidated VIEs
Variable Interest Entity [Line Items]
Current Assets: Other	257	203
Property, Plant and Equipment: Cost	6,394	5,747
Accumulated depreciation and amortization	(1,242)	(1,041)
Other Noncurrent Assets: Other	67	106
Current maturities of long-term debt	167	162
Long-Term Debt	1,569	1,541
Asset retirement obligations	148	127
Other Noncurrent Liabilities: Other	$ 316	$ 228