Variable Interest Entities (Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2013	Dec. 31, 2012
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	$ 1,531		$ 1,501		$ 1,296	$ 1,424
Restricted receivables of VIEs	2,199		1,719
Other current assets	1,661		1,821
Investments and other assets	3,251		3,432
Accumulated depreciation and amortization	(33,519)		(33,625)
Other deferred debits	183		181
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	1,892		2,391
Notes payable and commercial paper	1,737		839
Current maturities of long-term debt	885		2,104
Other current liabilities	1,612		1,996
Long-term debt	39,000		38,152
Deferred income taxes	11,852		12,097
Asset retirement obligation	4,994		4,950
Other liabilities	1,761		1,749
Noncontrolling interests	80		78
Duke Energy Carolinas [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	17		23		5	19
Restricted receivables of VIEs	705		673
Other current assets	269		309
Investments and other assets	994		1,000
Accumulated depreciation and amortization	(12,125)		(11,894)
Other deferred debits	45		46
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	540		701
Current maturities of long-term debt	47		47
Other current liabilities	348		393
Long-term debt	8,089		8,089
Deferred income taxes	5,727		5,706
Asset retirement obligation	1,617		1,594
Other liabilities	667		676
Duke Energy Progress [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	9		21		11	18
Restricted receivables of VIEs	538		417
Other current assets	300		296
Investments and other assets	459		443
Accumulated depreciation and amortization	(8,749)		(8,623)
Other deferred debits	35		32
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	344		420
Current maturities of long-term debt	6		174
Other current liabilities	329		392
Long-term debt	5,711		5,061
Deferred income taxes	2,658		2,557
Asset retirement obligation	1,758		1,729
Other liabilities	212		222
Duke Energy Florida [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	10		16		7	131
Restricted receivables of VIEs	318
Other current assets	64		182
Investments and other assets	252		252
Accumulated depreciation and amortization	(4,337)		(4,252)
Other deferred debits	44		44
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	311		333
Current maturities of long-term debt	11		11
Other current liabilities	406		445
Long-term debt	5,099		4,875
Deferred income taxes	1,816		1,829
Asset retirement obligation	829		833
Other liabilities	275		255
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	705		673
Other deferred debits	1		1
Total assets	706		674
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Long-term debt	400	[1]	400	[2]
Other liabilities			1
Total liabilities	400		401
Net assets of consolidated VIEs	306		273
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	538		416
Other deferred debits	1		1
Total assets	539		417
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Long-term debt	300	[1]	300	[2]
Other liabilities	1
Total liabilities	301		300
Net assets of consolidated VIEs	238		117
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted other assets of VIEs	318
Other deferred debits	1
Total assets	319
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Long-term debt	225	[1]
Other liabilities	1
Total liabilities	226
Net assets of consolidated VIEs	93
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	600		595
Total assets	600		595
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Long-term debt	325	[1]	325	[2]
Total liabilities	325		325
Net assets of consolidated VIEs	275		270
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	20		18
Other current assets	115		89
Investments and other assets	26		29
Property, plant and equipment, cost	1,663	[3]	1,662	[3]
Accumulated depreciation and amortization	(186)		(170)
Other deferred debits	33		34
Total assets	1,671		1,662
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	2		2
Taxes accrued	4		10
Current maturities of long-term debt	66		66
Other current liabilities	25		17
Long-term debt	907	[1]	907	[2]
Deferred income taxes	277		290
Asset retirement obligation	26		26
Other liabilities	23		17
Total liabilities	1,330		1,335
Net assets of consolidated VIEs	341		327
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	18		17
Other current assets	14		12
Investments and other assets	41		51
Property, plant and equipment, cost	18	[3]	18	[3]
Accumulated depreciation and amortization	(6)		(5)
Total assets	85		93
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Current maturities of long-term debt	15		14
Other current liabilities	10		10
Long-term debt	29	[1]	34	[2]
Other liabilities	10		13
Total liabilities	64		71
Net assets of consolidated VIEs	21		22
Total Consolidated VIE [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	2,199		1,719
Other current assets	129		101
Investments and other assets	67		80
Property, plant and equipment, cost	1,681	[3]	1,680	[3]
Accumulated depreciation and amortization	(192)		(175)
Other deferred debits	36		36
Total assets	3,920		3,441
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	2		2
Taxes accrued	4		10
Current maturities of long-term debt	81		80
Other current liabilities	35		27
Long-term debt	2,186	[1]	1,966	[2]
Deferred income taxes	277		290
Asset retirement obligation	26		26
Other liabilities	35		31
Total liabilities	2,646		2,432
Net assets of consolidated VIEs	$ 1,274		$ 1,009

[1] Non-recourse to the general assets of Duke Energy, Duke Energy Carolinas, Duke Energy Progress, and Duke Energy Florida.

[2] Non-recourse to the general assets of Duke Energy, Duke Energy Carolinas, and Duke Energy Progress.

[3] Restricted as collateral for non-recourse debt of VIEs.