Quarterly Financial Data (Schedule Of Quarterly Financial Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	$ 5,695	$ 6,722	$ 3,577	$ 3,630	$ 3,368	$ 3,964	$ 3,534	$ 3,663	$ 19,624	$ 14,529	$ 14,272
Operating income (loss)	767	1,078	786	495	517	767	679	814	3,126	2,777	2,461
Income From Continuing Operations	406	594	449	297	290	469	441	513	1,746	1,713	1,320
Net income	437	598	448	299	290	470	441	513	1,782	1,714	1,323
Net Income Attributable to Duke Energy Corporation	435	594	444	295	288	472	435	511	1,768	1,706	1,320
Basic	$ 0.57	$ 0.84	$ 0.99	$ 0.66	$ 0.65	$ 1.06	$ 0.98	$ 1.15	$ 3.01	$ 3.83	$ 2.99
Diluted	$ 0.57	$ 0.84	$ 0.99	$ 0.66	$ 0.65	$ 1.06	$ 0.98	$ 1.15	$ 3.01	$ 3.83	$ 2.99
Basic	$ 0.62	$ 0.85	$ 0.99	$ 0.66	$ 0.65	$ 1.06	$ 0.98	$ 1.15	$ 3.07	$ 3.83	$ 3.00
Diluted	$ 0.62	$ 0.85	$ 0.99	$ 0.66	$ 0.65	$ 1.06	$ 0.98	$ 1.15	$ 3.07	$ 3.83	$ 3.00
Duke Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,609	1,939	1,616	1,501	1,466	1,868	1,607	1,552	6,665	6,493	6,424
Operating income (loss)	216	440	386	475	245	541	331	363	1,517	1,480	1,445
Net income	130	258	211	266	125	311	193	205	865	834	838
Progress Energy [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	2,227	2,788	2,288	2,102	1,752	2,753	2,269	2,174	9,405	8,948	10,223
Operating income (loss)	118	379	277	363	16	687	433	447	1,137	1,583	2,044
Income From Continuing Operations	(8)	154	68	141	(73)	293	180	187	355	587	867
Net income	34	157	64	152	(74)	293	178	185	407	582	863
Net Income Attributable to Duke Energy Corporation	32	155	63	150	(76)	291	176	184	400	575	856
Basic			$ 0.23	$ 0.47	$ (0.25)	$ 0.98	$ 0.60	$ 0.63
Diluted			$ 0.23	$ 0.47	$ (0.25)	$ 0.98	$ 0.60	$ 0.63
Basic			$ 0.21	$ 0.51	$ (0.25)	$ 0.98	$ 0.60	$ 0.62
Diluted			$ 0.21	$ 0.51	$ (0.25)	$ 0.98	$ 0.60	$ 0.62
Progress Energy Carolinas [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,128	1,398	1,090	1,090	1,013	1,331	1,069	1,134	4,706	4,547	4,933
Operating income (loss)	148	172	83	107	133	324	196	223	510	876	1,067
Net income	93	96	31	52	79	199	107	131	272	516	602
Net Income Attributable to Duke Energy Corporation									272	516	603
Progress Energy Florida [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	1,095	1,388	1,196	1,010	737	1,419	1,199	1,037	4,689	4,392	5,276
Operating income (loss)	(29)	207	196	255	(112)	363	236	216	629	703	955
Net income	(45)	100	83	128	(104)	203	113	102	266	314	453
Duke Energy Ohio [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	766	757	717	912	770	838	694	879	3,152	3,181	3,329
Operating income (loss)	74	42	95	138	65	116	59	135	349	375	(225)
Net income	42	14	45	74	37	51	33	73	175	194	(441)
Duke Energy Indiana [Member]
Quarterly Financial Information Disclosure [Line Items]
Operating revenues	626	718	685	688	625	718	620	659	2,717	2,622	2,520
Operating income (loss)	93	(30)	134	(272)	85	(42)	109	130	(75)	282	506
Net income	$ 59	$ (19)	$ 77	$ (167)	$ 55	$ (31)	$ 68	$ 76	$ (50)	$ 168	$ 285