Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	$ 1,918	$ 2,005
Other, current assets	1,267	1,049
Regulatory assets, noncurrent	13,393	13,617
Property, plant and equipment, cost	141,363	134,458
Accumulated depreciation and amortization	(44,482)	(43,126)
Other noncurrent assets	2,975	2,935
Current Liabilities: Other	2,020	2,085
Current maturities of long-term debt	2,698	3,406
Long-Term Debt	54,342	51,123
Other Noncurrent Liabilities: Asset Retirement Obligations	11,889	9,548
Other Noncurrent Liabilities: Other	1,583	1,650
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	605	520
Other, current assets	17	72
Regulatory assets, noncurrent	3,392	3,457
Property, plant and equipment, cost	47,249	44,741
Accumulated depreciation and amortization	(16,047)	(15,496)
Other noncurrent assets	1,085	1,027
Current Liabilities: Other	499	571
Current maturities of long-term debt	456	6
Long-Term Debt	10,208	10,633
Other Noncurrent Liabilities: Asset Retirement Obligations	5,139	3,659
Other Noncurrent Liabilities: Other	645	671
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	572	703
Other, current assets	34	62
Regulatory assets, noncurrent	4,124	4,111
Property, plant and equipment, cost	33,288	31,459
Accumulated depreciation and amortization	(11,728)	(11,423)
Other noncurrent assets	586	612
Current Liabilities: Other	395	408
Current maturities of long-term debt	6	603
Long-Term Debt	8,893	7,451
Other Noncurrent Liabilities: Asset Retirement Obligations	5,203	4,311
Other Noncurrent Liabilities: Other	91	106
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Regulatory assets, current	452	434
Other, current assets	46	46
Regulatory assets, noncurrent	2,299	2,454
Property, plant and equipment, cost	19,461	18,792
Accumulated depreciation and amortization	(5,073)	(4,968)
Other noncurrent assets	311	311
Current Liabilities: Other	461	406
Current maturities of long-term debt	671	270
Long-Term Debt	6,542	7,051
Other Noncurrent Liabilities: Asset Retirement Obligations	574	586
Other Noncurrent Liabilities: Other	104	93
DEFPF [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	8	5
Regulatory assets, current	52	52
Other, current assets	31	39
Regulatory assets, noncurrent	1,019	1,041
Current Liabilities: Other	10	10
Current maturities of long-term debt	54	53
Long-Term Debt	1,082	1,111
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	671	699
Long-Term Debt	475	450
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	518	547
Long-Term Debt	325	300
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	472	357
Long-Term Debt	250	225
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Receivables of VIEs	484	564
Long-Term Debt	328	325
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Other, current assets	109	123
Property, plant and equipment, cost	4,419	4,007
Accumulated depreciation and amortization	(769)	(698)
Other noncurrent assets	289	261
Current maturities of long-term debt	178	174
Long-Term Debt	1,610	1,587
Other Noncurrent Liabilities: Asset Retirement Obligations	108	106
Other Noncurrent Liabilities: Other	$ 222	$ 212