Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 1,782	$ 1,714	$ 1,323
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	2,652	2,026	1,994
Equity component of AFUDC	(300)	(260)	(234)
Severance expense	92	0	0
FERC mitigation costs	117	0	0
Community support and charitable contributions expense	92	0	0
(Gains) losses on sales of other assets	(44)	(19)	(268)
Impairment charges	586	335	738
Deferred income taxes	584	602	741
Voluntary opportunity cost deferral	(101)	0	0
Equity in earnings of unconsolidated affiliates	(148)	(160)	(116)
Accrued pension and other post-retirement benefit costs	239	104	117
Contributions to qualified pension plans	(304)	(200)	(400)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	60	(48)	15
Receivables	39	2	19
Inventory	(258)	(247)	198
Other current assets	140	185	227
Increase (decrease) in
Accounts payable	131	41	167
Taxes accrued	(142)	27	30
Other current liabilities	295	(254)	43
Other assets	(129)	12	157
Other liabilities	(139)	(188)	(240)
Net cash provided (used) by operating activities	5,244	3,672	4,511
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(5,501)	(4,363)	(4,803)
Investment expenditures	(6)	(50)	(52)
Acquisitions	(451)	(51)	0
Cash Acquired from Acquisition	71	0	0
Purchases of available-for-sale securities	(4,719)	(3,194)	(2,166)
Proceeds from sales and maturities of available-for-sale securities	4,537	3,063	2,261
Net proceeds from the sales of other assets, and sales of and collections on notes receivable	212	118	406
Change in restricted cash	(414)	22	(75)
Other	74	21	6
Net cash (used) provided in investing activities	(6,197)	(4,434)	(4,423)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	4,170	2,570	2,738
Proceeds from the issuance of common stock related to employee benefit plans	23	67	302
Payments for the redemption of long-term debt	(2,498)	(278)	(1,647)
Notes payable and commercial paper	278	208	(55)
Distributions to noncontrolling interests	(25)	(26)	(10)
Contributions from Noncontrolling Interests	76	0	0
Dividends paid	(1,752)	(1,329)	1,284
Other	(5)	(10)	(4)
Net cash provided (used) in financing activities	267	1,202	40
Net increase (decrease) in cash and cash equivalents	(686)	440	128
Cash and cash equivalents at beginning of period	2,110	1,670	1,542
Cash and cash equivalents at end of period	1,424	2,110	1,670
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	1,032	813	795
Cash paid for (received from) income taxes	72	26	64
Merger with Progress Energy
Fair Value of Assets Acquired	48,944
Liabilities assumed	30,873
Issuance of common stock	18,071
Significant Non-cash Transactions
Accrued capital expenditures	684	409	361
Extinguishment of debt related to investment in Attiki Gas Supply, S.A.	66
Debt associated with consolidation of variable interest entities			342
Duke Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	865	834	838
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	1,143	1,020	984
Equity component of AFUDC	(154)	(168)	(174)
FERC mitigation costs	46	0	0
Community support and charitable contributions expense	56	0	0
(Gains) losses on sales of other assets	(12)	(1)	(7)
Impairment charges	0	12	0
Deferred income taxes	479	564	456
Voluntary opportunity cost deferral	(101)	0	0
Accrued pension and other post-retirement benefit costs	41	32	34
Contributions to qualified pension plans	0	(33)	(158)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	0	(91)	1
Receivables	22	22	114
Receivables from affiliated companies	(1)	88	(90)
Inventory	(128)	(177)	134
Other current assets	46	144	(55)
Increase (decrease) in
Accounts payable	(51)	120	86
Accounts payable to affiliated companies	(28)	(39)	25
Taxes accrued	(12)	12	(23)
Other current liabilities	165	(170)	4
Other assets	(117)	(46)	19
Other liabilities	(126)	(249)	(158)
Net cash provided (used) by operating activities	2,133	1,874	2,030
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,908)	(2,272)	(2,280)
Purchases of available-for-sale securities	(2,481)	(2,227)	(1,045)
Proceeds from sales and maturities of available-for-sale securities	2,445	2,179	1,066
Notes receivable from affiliated companies	541	(584)	250
Change in restricted cash	0	2	7
Other	(12)	(13)	0
Net cash (used) provided in investing activities	(1,415)	(2,915)	(2,002)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	645	1,498	692
Payments for the redemption of long-term debt	(1,177)	(7)	(607)
Dividend to parent	(450)	(299)	(350)
Other	(6)	(15)	(4)
Net cash provided (used) in financing activities	(988)	1,177	(269)
Net increase (decrease) in cash and cash equivalents	(270)	136	(241)
Cash and cash equivalents at beginning of period	289	153	394
Cash and cash equivalents at end of period	19	289	153
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	385	337	342
Cash paid for (received from) income taxes	(38)	(223)	69
Significant Non-cash Transactions
Accrued capital expenditures	194	209	181
Progress Energy [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	407	582	863
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	897	850	1,044
Equity component of AFUDC	(106)	(103)	(92)
Severance expense	38	0	0
FERC mitigation costs	71	0	0
Community support and charitable contributions expense	36	0	0
(Gains) losses on sales of other assets	(16)	(5)	9
Impairment charges	146	3	5
Deferred income taxes	263	353	478
Amounts to be refunded to customers	100	288	0
Accrued pension and other post-retirement benefit costs	179	124	121
Contributions to qualified pension plans	(346)	(331)	(129)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	7	(10)	(17)
Receivables	49	167	(178)
Receivables from affiliated companies	(15)	0	0
Inventory	(71)	(210)	89
Other current assets	2	(111)	84
Increase (decrease) in
Accounts payable	175	(64)	115
Accounts payable to affiliated companies	30	0	0
Taxes accrued	25	(16)	26
Other current liabilities	81	67	78
Other assets	(25)	(67)	(25)
Other liabilities	(87)	98	60
Net cash provided (used) by operating activities	1,840	1,615	2,531
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,366)	(2,256)	(2,445)
Purchases of available-for-sale securities	(1,374)	(5,017)	(7,009)
Proceeds from sales and maturities of available-for-sale securities	1,325	4,970	6,990
Insurance proceeds	7	79	64
Change in restricted cash	24	(24)	0
Other	102	36	0
Net cash (used) provided in investing activities	(2,282)	(2,212)	(2,400)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	2,074	1,286	591
Proceeds from the issuance of common stock related to employee benefit plans	6	53	434
Payments for the redemption of long-term debt	(962)	(1,010)	(410)
Payments of short-term debt with original maturities greater than 90 days	(65)	0	0
Proceeds from issuance of short-term debt with original maturities greater than 90 days	65	0	0
Notes payable and commercial paper	(671)	667	(140)
Notes payable to affiliated companies	455	0	0
Distributions to noncontrolling interests	(7)	(7)	(6)
Dividends paid	(445)	(734)	(717)
Other	(7)	(39)	3
Net cash provided (used) in financing activities	443	216	(245)
Net increase (decrease) in cash and cash equivalents	1	(381)	(114)
Cash and cash equivalents at beginning of period	230	611	725
Cash and cash equivalents at end of period	231	230	611
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	784	793	709
Cash paid for (received from) income taxes	(4)	(78)	(56)
Significant Non-cash Transactions
Accrued capital expenditures	375	380	364
Asset retirement obligation additions and estimate revisions	837	(4)	(36)
Capital expenditures financed through capital leases	140	0	0
Progress Energy Carolinas [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	272	516	602
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	676	654	593
Equity component of AFUDC	(69)	(71)	(64)
Severance expense	18	0	0
FERC mitigation costs	71	0	0
Community support and charitable contributions expense	36	0	0
(Gains) losses on sales of other assets	(1)	(3)	(1)
Impairment charges	0	3	5
Deferred income taxes	164	262	285
Accrued pension and other post-retirement benefit costs	70	43	43
Contributions to qualified pension plans	(141)	(217)	(95)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(25)	(23)	(11)
Receivables	2	84	(68)
Receivables from affiliated companies	(4)	8	5
Inventory	(58)	(182)	83
Other current assets	(24)	116	22
Increase (decrease) in
Accounts payable	149	(22)	49
Accounts payable to affiliated companies	47	(45)	20
Taxes accrued	(5)	(4)	(4)
Other current liabilities	23	40	39
Other assets	(28)	(38)	(22)
Other liabilities	(6)	16	37
Net cash provided (used) by operating activities	1,167	1,137	1,518
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(1,525)	(1,426)	(1,382)
Purchases of available-for-sale securities	(582)	(572)	(490)
Proceeds from sales and maturities of available-for-sale securities	532	515	437
Notes receivable from affiliated companies	0	2	202
Other	91	12	3
Net cash (used) provided in investing activities	(1,484)	(1,469)	(1,230)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	988	495	0
Payments for the redemption of long-term debt	(502)	(2)	(1)
Contributions from parent	0	0	14
Notes payable and commercial paper	(188)	185	0
Notes payable to affiliated companies	333	31	0
Dividend to parent	(310)	(585)	(100)
Dividends paid on preferred stock	(3)	(3)	(3)
Other	(3)	1	(3)
Net cash provided (used) in financing activities	315	122	(93)
Net increase (decrease) in cash and cash equivalents	(2)	(210)	195
Cash and cash equivalents at beginning of period	20	230	35
Cash and cash equivalents at end of period	18	20	230
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	249	199	166
Cash paid for (received from) income taxes	19	(97)	108
Significant Non-cash Transactions
Accrued capital expenditures	232	270	247
Asset retirement obligation additions and estimate revisions	698	(4)	1
Capital expenditures financed through capital leases	140	0	0
Progress Energy Florida [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	266	314	453
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	197	174	430
Equity component of AFUDC	(37)	(32)	(28)
Severance expense	6	0	0
(Gains) losses on sales of other assets	(2)	(2)	5
Impairment charges	146	0	0
Deferred income taxes	142	234	324
Amounts to be refunded to customers	100	288	0
Accrued pension and other post-retirement benefit costs	71	52	58
Contributions to qualified pension plans	(128)	(112)	(34)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	73	(13)	(7)
Receivables	37	91	(95)
Receivables from affiliated companies	(13)	(6)	(1)
Inventory	(13)	(28)	6
Other current assets	22	(160)	(85)
Increase (decrease) in
Accounts payable	21	(45)	76
Accounts payable to affiliated companies	30	(37)	(4)
Taxes accrued	15	(8)	53
Other current liabilities	51	16	45
Other assets	8	(7)	1
Other liabilities	(94)	46	7
Net cash provided (used) by operating activities	898	765	1,204
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(809)	(813)	(1,055)
Purchases of available-for-sale securities	(791)	(4,435)	(6,386)
Proceeds from sales and maturities of available-for-sale securities	791	4,438	6,390
Notes receivable from affiliated companies	(207)	0	0
Insurance proceeds	7	76	64
Other	9	27	0
Net cash (used) provided in investing activities	(1,000)	(707)	(987)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	642	296	591
Payments for the redemption of long-term debt	(10)	(309)	(308)
Payments of short-term debt with original maturities greater than 90 days	(65)	0	0
Proceeds from issuance of short-term debt with original maturities greater than 90 days	65	0	0
Notes payable and commercial paper	(233)	233	0
Notes payable to affiliated companies	(8)	0	(212)
Dividend to parent	(170)	(510)	(50)
Dividends paid on preferred stock	(2)	(2)	(2)
Other	(2)	1	(4)
Net cash provided (used) in financing activities	217	(291)	15
Net increase (decrease) in cash and cash equivalents	115	(233)	232
Cash and cash equivalents at beginning of period	16	249	17
Cash and cash equivalents at end of period	131	16	249
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	266	287	241
Cash paid for (received from) income taxes	24	(83)	(98)
Significant Non-cash Transactions
Accrued capital expenditures	139	106	112
Asset retirement obligation additions and estimate revisions	139	0	(19)
Duke Energy Ohio [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	175	194	(441)
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	342	338	403
Equity component of AFUDC	(6)	(5)	(4)
(Gains) losses on sales of other assets	(7)	(5)	(3)
Impairment charges	2	89	837
Deferred income taxes	61	190	17
Accrued pension and other post-retirement benefit costs	11	14	12
Contributions to qualified pension plans	0	(48)	(45)
(Increase) decrease in
Net realized and unrealized mark-to-market and hedging transactions	(5)	(8)	(18)
Receivables	29	10	191
Receivables from affiliated companies	61	98	(221)
Inventory	15	11	15
Other current assets	(62)	(24)	71
Increase (decrease) in
Accounts payable	5	(33)	87
Accounts payable to affiliated companies	(22)	1	(108)
Taxes accrued	(24)	8	25
Other current liabilities	(21)	(3)	6
Other assets	0	(61)	42
Other liabilities	(116)	47	(15)
Net cash provided (used) by operating activities	444	818	855
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(514)	(499)	(446)
Net proceeds from the sales of other assets, and sales of and collections on notes receivable	82	0	0
Notes receivable from affiliated companies	400	79	(296)
Change in restricted cash	0	(26)	0
Other	6	(3)	2
Net cash (used) provided in investing activities	(26)	(449)	(740)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	0	0	34
Payments for the redemption of long-term debt	(556)	(9)	(36)
Notes payable and commercial paper	0	0	(12)
Notes payable to affiliated companies	245	0	0
Dividend to parent	(175)	(485)	0
Other	0	(4)	0
Net cash provided (used) in financing activities	(486)	(498)	(14)
Net increase (decrease) in cash and cash equivalents	(68)	(129)	101
Cash and cash equivalents at beginning of period	99	228	127
Cash and cash equivalents at end of period	31	99	228
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	93	100	108
Cash paid for (received from) income taxes	18	(102)	114
Significant Non-cash Transactions
Accrued capital expenditures	31	43	40
Transfer of Vermillion Generating Station	28
Duke Energy Indiana [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	(50)	168	285
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, amortization and accretion (including amortization of nuclear fuel)	393	395	380
Equity component of AFUDC	(84)	(88)	(56)
(Gains) losses on sales of other assets	0	0	2
Impairment charges	579	234	44
Deferred income taxes	(74)	(63)	143
Accrued pension and other post-retirement benefit costs	15	23	23
Contributions to qualified pension plans	0	(52)	(46)
(Increase) decrease in
Receivables	6	25	105
Receivables from affiliated companies	52	63	(204)
Inventory	(50)	(64)	46
Other current assets	(25)	13	(14)
Increase (decrease) in
Accounts payable	18	(14)	39
Accounts payable to affiliated companies	(12)	5	(60)
Taxes accrued	(27)	29	0
Other current liabilities	6	(16)	17
Other assets	6	47	4
Other liabilities	(37)	(72)	(46)
Net cash provided (used) by operating activities	716	633	662
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(718)	(1,066)	(1,255)
Purchases of available-for-sale securities	(17)	(11)	(24)
Proceeds from sales and maturities of available-for-sale securities	18	8	25
Notes receivable from affiliated companies	0	115	(84)
Change in restricted cash	0	6	(6)
Other	(1)	(5)	(2)
Net cash (used) provided in investing activities	(718)	(953)	(1,346)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	250	0	571
Payments for the redemption of long-term debt	(7)	(14)	(199)
Contributions from parent	0	0	350
Notes payable to affiliated companies	(219)	300	0
Other	(2)	(4)	(4)
Net cash provided (used) in financing activities	22	282	718
Net increase (decrease) in cash and cash equivalents	20	(38)	34
Cash and cash equivalents at beginning of period	16	54	20
Cash and cash equivalents at end of period	36	16	54
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	130	130	122
Cash paid for (received from) income taxes	57	90	31
Significant Non-cash Transactions
Accrued capital expenditures	67	110	131
Transfer of Vermillion Generating Station	$ 26	$ 0	$ 0