Variable Interest Entities (Consolidated VIEs) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 857	$ 2,036	$ 1,501	$ 1,424
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	1,748	1,973
Other current assets	327	1,837
Investments and other assets	3,042	3,008
Total property, plant and equipment	112,826	104,861
Accumulated depreciation and amortization	(37,665)	(34,824)
Other deferred debits	43	19
Accounts payable	2,400	2,271
Current maturities of long-term debt	2,074	2,807
Other current liabilities	2,115	2,188
Long-Term debt	37,495	37,061
Deferred income taxes	12,705	13,423
Asset retirement obligations	10,264	8,466
Other Liabilities	1,706	1,675
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	2
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	1,748	1,973
Other current assets	142	74
Investments and other assets	70	50
Total property, plant and equipment	2,035	1,873
Accumulated depreciation and amortization	(327)	(255)
Other deferred debits		36
Total assets	3,670	3,751
Accounts payable	35	3
Taxes accrued	14	6
Current maturities of long-term debt	125	84
Other current liabilities	17	21
Long-Term debt	2,197	2,234
Deferred income taxes	289	283
Asset retirement obligations	35	29
Other Liabilities	33	38
Total liabilities	2,745	2,698
Net assets of consolidated VIEs	925	1,053
Duke Energy Carolinas [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	13	13	23	19
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	596	647
Other current assets	128	77
Investments and other assets	999	959
Total property, plant and equipment	39,398	37,372
Accumulated depreciation and amortization	(13,521)	(12,700)
Other deferred debits	4	4
Accounts payable	753	709
Current maturities of long-term debt	356	507
Other current liabilities	519	434
Long-Term debt	7,711	7,546
Deferred income taxes	6,146	5,812
Asset retirement obligations	3,918	3,428
Other Liabilities	621	642
Duke Energy Progress [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	15	9	21	18
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	349	436
Other current assets	121	384
Investments and other assets	486	412
Total property, plant and equipment	27,313	24,207
Accumulated depreciation and amortization	(10,141)	(9,021)
Other deferred debits	3	3
Accounts payable	399	481
Current maturities of long-term debt	2	945
Other current liabilities	412	409
Long-Term debt	6,366	5,225
Deferred income taxes	3,027	2,908
Asset retirement obligations	4,567	3,905
Other Liabilities	45	89
Duke Energy Florida [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	8	8	$ 16	$ 131
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	308	305
Other current assets	21	521
Investments and other assets	292	204
Total property, plant and equipment	15,343	14,433
Accumulated depreciation and amortization	(4,720)	(4,478)
Other deferred debits	2	2
Accounts payable	322	365
Current maturities of long-term debt	13	562
Other current liabilities	452	586
Long-Term debt	4,253	4,261
Deferred income taxes	2,460	2,452
Asset retirement obligations	802	806
Other Liabilities	146	158
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	596	647
Total assets	596	647
Taxes accrued	5
Long-Term debt	425	400
Total liabilities	430	400
Net assets of consolidated VIEs	166	247
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	349	436
Total assets	349	436
Taxes accrued	3
Long-Term debt	254	300
Total liabilities	257	300
Net assets of consolidated VIEs	92	136
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	309	305
Total assets	309	305
Long-Term debt	225	$ 225
Deferred income taxes
Asset retirement obligations
Other Liabilities
Total liabilities	225	$ 225
Net assets of consolidated VIEs	84	80
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	454	547
Total assets	454	547
Long-Term debt	325	325
Total liabilities	325	325
Net assets of consolidated VIEs	129	222
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	19	20
Other current assets	138	68
Investments and other assets	70	25
Total property, plant and equipment	2,015	1,855
Accumulated depreciation and amortization	(321)	(250)
Other deferred debits		34
Total assets	1,921	1,752
Accounts payable	35	3
Taxes accrued	5	6
Current maturities of long-term debt	108	68
Other current liabilities	15	16
Long-Term debt	968	967
Deferred income taxes	289	283
Asset retirement obligations	35	29
Other Liabilities	33	34
Total liabilities	1,488	1,406
Net assets of consolidated VIEs	433	346
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount, Assets and Liabilities, Net [Abstract]
Cash and Cash Equivalents, at Carrying Value	2
Restricted receivables of variable interest entities (net of allowance for doubtful accounts)	21	18
Other current assets	4	6
Investments and other assets		25
Total property, plant and equipment	20	18
Accumulated depreciation and amortization	(6)	(5)
Other deferred debits		2
Total assets	41	64
Taxes accrued	1
Current maturities of long-term debt	17	16
Other current liabilities	2	5
Long-Term debt		17
Deferred income taxes	0
Other Liabilities		4
Total liabilities	20	42
Net assets of consolidated VIEs	$ 21	$ 22