Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entities [Line Items]
Regulatory Assets: Current	$ 1,793	$ 1,641
Current Assets: Other	722	462
Other Noncurrent Assets: Regulatory assets	12,485	12,421
Property, Plant and Equipment: Cost	158,272	155,580
Accumulated depreciation and amortization	(49,752)	(48,827)
Other Noncurrent Assets: Other	3,652	3,601
Current Liabilities: Other	1,994	2,936
Current maturities of long-term debt	4,976	4,238
Long-Term Debt	57,410	55,625
Other Noncurrent Liabilities: AROs	12,272	12,286
Other Noncurrent Liabilities: Other	1,809	1,719
Duke Energy Florida
Variable Interest Entities [Line Items]
Regulatory Assets: Current	407	265
Current Assets: Other	59	41
Other Noncurrent Assets: Regulatory assets	1,701	1,799
Property, Plant and Equipment: Cost	22,933	22,123
Accumulated depreciation and amortization	(5,746)	(5,560)
Other Noncurrent Assets: Other	342	335
Current Liabilities: Other	395	374
Current maturities of long-term debt	575	823
Long-Term Debt	7,306	7,092
Other Noncurrent Liabilities: AROs	467	514
Other Noncurrent Liabilities: Other	262	209
DEFPF | Duke Energy Florida | VIE primary beneficiary
Variable Interest Entities [Line Items]
Receivables of VIEs	6	4
Regulatory Assets: Current	54	53
Current Assets: Other	33	39
Other Noncurrent Assets: Regulatory assets	914	937
Current Liabilities: Other	9	10
Current maturities of long-term debt	55	55
Long-Term Debt	973	1,002
Commercial Renewables | VIE primary beneficiary
Variable Interest Entities [Line Items]
Current Assets: Other	323	257
Property, Plant and Equipment: Cost	6,876	6,394
Accumulated depreciation and amortization	(1,354)	(1,242)
Other Noncurrent Assets: Other	73	67
Current maturities of long-term debt	164	167
Long-Term Debt	1,497	1,569
Other Noncurrent Liabilities: AROs	155	148
Other Noncurrent Liabilities: Other	$ 352	$ 316