Variable Interest Entities (Schedule of Consolidated VIEs) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 6,179	$ 857	$ 1,370	$ 2,036
Restricted receivables of VIEs	2,139	1,748
Regulatory Assets, Current	853	877
Other current assets	429	327
Regulatory Assets, Noncurrent	11,896	11,373
Interest accrued	504	430
Investments and other assets	2,948	3,042
Property, plant and equipment, cost	116,376	112,826
Accumulated depreciation and amortization	(38,812)	(37,665)
Other deferred debits	22	43
Accounts payable	2,138	2,400
Current maturities of long-term debt	3,201	2,074
Other current liabilities	1,728	2,115
Long-Term Debt	43,964	37,495
Deferred income taxes	13,201	12,705
Asset retirement obligations	10,291	10,264
Other liabilities	1,851	1,706
Duke Energy Carolinas [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	82	13	198	13
Restricted receivables of VIEs	780	596
Regulatory Assets, Current	256	305
Other current assets	22	128
Regulatory Assets, Noncurrent	3,040	2,766
Interest accrued	125	95
Investments and other assets	923	999
Property, plant and equipment, cost	40,495	39,398
Accumulated depreciation and amortization	(14,125)	(13,521)
Other deferred debits	3	4
Accounts payable	582	753
Current maturities of long-term debt	468	356
Other current liabilities	417	519
Long-Term Debt	8,592	7,711
Deferred income taxes	6,464	6,146
Asset retirement obligations	3,622	3,918
Other liabilities	685	621
Duke Energy Progress [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	136	15	123	9
Restricted receivables of VIEs	473	349
Regulatory Assets, Current	186	264
Other current assets	83	121
Regulatory Assets, Noncurrent	3,093	2,710
Interest accrued	81	96
Investments and other assets	518	486
Property, plant and equipment, cost	28,001	27,313
Accumulated depreciation and amortization	(10,508)	(10,141)
Other deferred debits	2	3
Accounts payable	319	399
Current maturities of long-term debt	252	2
Other current liabilities	326	412
Long-Term Debt	6,609	6,366
Deferred income taxes	3,279	3,027
Asset retirement obligations	4,623	4,567
Other liabilities	23	45
Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	10	8	$ 16	$ 8
Restricted receivables of VIEs	385	308
Regulatory Assets, Current	161	98
Other current assets	46	21
Regulatory Assets, Noncurrent	2,559	2,725
Interest accrued	58	43
Investments and other assets	292	292
Property, plant and equipment, cost	16,139	15,343
Accumulated depreciation and amortization	(4,654)	(4,720)
Other deferred debits	2	2
Accounts payable	354	322
Current maturities of long-term debt	326	13
Other current liabilities	367	452
Long-Term Debt	5,802	4,253
Deferred income taxes	2,597	2,460
Asset retirement obligations	798	802
Other liabilities	167	146
DEFPF [Member] | Duke Energy Florida [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of VIEs	7
Regulatory Assets, Current	51
Other current assets	29
Regulatory Assets, Noncurrent	1,156
Interest accrued	9
Current maturities of long-term debt	62
Long-Term Debt	1,216
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	425	425
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	300	254
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	225	225
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Long-Term Debt	325	325
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Other current assets	252	138
Property, plant and equipment, cost	2,583	2,015
Accumulated depreciation and amortization	(400)	(321)
Current maturities of long-term debt	193	108
Long-Term Debt	1,151	968
Deferred income taxes	50	289
Other liabilities	$ 270	$ 33