Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Variable Interest Entities [Line Items]
Regulatory Assets: Current	$ 1,650	$ 1,641
Current Assets: Other	619	462
Other Noncurrent Assets: Regulatory assets	12,441	12,421
Property, Plant and Equipment: Cost	157,372	155,580
Accumulated depreciation and amortization	(49,772)	(48,827)
Other Noncurrent Assets: Other	3,715	3,601
Current Liabilities: Other	1,858	2,936
Current maturities of long-term debt	5,586	4,238
Long-Term Debt	54,768	55,625
Other Noncurrent Liabilities: AROs	12,299	12,286
Other Noncurrent Liabilities: Other	1,769	1,719
Duke Energy Florida
Variable Interest Entities [Line Items]
Regulatory Assets: Current	352	265
Current Assets: Other	82	41
Other Noncurrent Assets: Regulatory assets	1,717	1,799
Property, Plant and Equipment: Cost	22,459	22,123
Accumulated depreciation and amortization	(5,646)	(5,560)
Other Noncurrent Assets: Other	355	335
Current Liabilities: Other	356	374
Current maturities of long-term debt	824	823
Long-Term Debt	7,060	7,092
Other Noncurrent Liabilities: AROs	493	514
Other Noncurrent Liabilities: Other	267	209
DEFPF | Duke Energy Florida | VIE primary beneficiary
Variable Interest Entities [Line Items]
Receivables of VIEs	4	4
Regulatory Assets: Current	54	53
Current Assets: Other	14	39
Other Noncurrent Assets: Regulatory assets	927	937
Current Liabilities: Other	2	10
Current maturities of long-term debt	55	55
Long-Term Debt	972	1,002
Commercial Renewables | VIE primary beneficiary
Variable Interest Entities [Line Items]
Current Assets: Other	319	257
Property, Plant and Equipment: Cost	6,860	6,394
Accumulated depreciation and amortization	(1,297)	(1,242)
Other Noncurrent Assets: Other	66	67
Current maturities of long-term debt	167	167
Long-Term Debt	1,584	1,569
Other Noncurrent Liabilities: AROs	153	148
Other Noncurrent Liabilities: Other	$ 331	$ 316