Fair Value Of Financial Assets and Liabilities (Fair Value Measurement Amounts for Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2013 Level 1 [Member]		Dec. 31, 2012 Level 1 [Member]		Sep. 30, 2013 Level 2 [Member]		Dec. 31, 2012 Level 2 [Member]		Sep. 30, 2013 Level 3 [Member]		Dec. 31, 2012 Level 3 [Member]		Sep. 30, 2013 Auction Rate Securities [Member]		Dec. 31, 2012 Auction Rate Securities [Member]		Sep. 30, 2013 Auction Rate Securities [Member] Level 3 [Member]		Dec. 31, 2012 Auction Rate Securities [Member] Level 3 [Member]		Sep. 30, 2013 NDTF [Member] Equity Securities [Member]	Dec. 31, 2012 NDTF [Member] Equity Securities [Member]	Sep. 30, 2013 NDTF [Member] Equity Securities [Member] Level 1 [Member]	Dec. 31, 2012 NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2013 NDTF [Member] Equity Securities [Member] Level 2 [Member]	Dec. 31, 2012 NDTF [Member] Equity Securities [Member] Level 2 [Member]	Sep. 30, 2013 NDTF [Member] Equity Securities [Member] Level 3 [Member]	Dec. 31, 2012 NDTF [Member] Equity Securities [Member] Level 3 [Member]	Sep. 30, 2013 NDTF [Member] Debt Securities [Member]	Dec. 31, 2012 NDTF [Member] Debt Securities [Member]	Sep. 30, 2013 NDTF [Member] Debt Securities [Member] Level 1 [Member]	Dec. 31, 2012 NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2013 NDTF [Member] Debt Securities [Member] Level 2 [Member]	Dec. 31, 2012 NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2013 NDTF [Member] Debt Securities [Member] Level 3 [Member]	Dec. 31, 2012 NDTF [Member] Debt Securities [Member] Level 3 [Member]	Sep. 30, 2013 Other Classification [Member] Equity Securities [Member]		Dec. 31, 2012 Other Classification [Member] Equity Securities [Member]		Sep. 30, 2013 Other Classification [Member] Equity Securities [Member] Level 1 [Member]		Dec. 31, 2012 Other Classification [Member] Equity Securities [Member] Level 1 [Member]		Sep. 30, 2013 Other Classification [Member] Equity Securities [Member] Level 2 [Member]		Dec. 31, 2012 Other Classification [Member] Equity Securities [Member] Level 2 [Member]		Sep. 30, 2013 Other Classification [Member] Debt Securities [Member]		Dec. 31, 2012 Other Classification [Member] Debt Securities [Member]		Sep. 30, 2013 Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Dec. 31, 2012 Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Sep. 30, 2013 Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Dec. 31, 2012 Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Carolinas [Member]		Dec. 31, 2012 Duke Energy Carolinas [Member]		Sep. 30, 2013 Duke Energy Carolinas [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Level 2 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Level 3 [Member]		Dec. 31, 2012 Duke Energy Carolinas [Member] Level 3 [Member]		Sep. 30, 2013 Duke Energy Carolinas [Member] Auction Rate Securities [Member]		Dec. 31, 2012 Duke Energy Carolinas [Member] Auction Rate Securities [Member]		Sep. 30, 2013 Duke Energy Carolinas [Member] Auction Rate Securities [Member] Level 3 [Member]		Dec. 31, 2012 Duke Energy Carolinas [Member] Auction Rate Securities [Member] Level 3 [Member]		Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 3 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Equity Securities [Member] Level 3 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 3 [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] NDTF [Member] Debt Securities [Member] Level 3 [Member]	Sep. 30, 2013 Progress Energy [Member]		Dec. 31, 2012 Progress Energy [Member]		Sep. 30, 2013 Progress Energy [Member] Level 1 [Member]	Dec. 31, 2012 Progress Energy [Member] Level 1 [Member]	Sep. 30, 2013 Progress Energy [Member] Level 2 [Member]		Dec. 31, 2012 Progress Energy [Member] Level 2 [Member]		Dec. 31, 2012 Progress Energy [Member] Level 3 [Member]		Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Equity Securities [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Equity Securities [Member]	Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Debt Securities [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Debt Securities [Member]	Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2013 Progress Energy [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Dec. 31, 2012 Progress Energy [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2013 Progress Energy [Member] Other Classification [Member] Debt Securities [Member]		Dec. 31, 2012 Progress Energy [Member] Other Classification [Member] Debt Securities [Member]		Sep. 30, 2013 Progress Energy [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Dec. 31, 2012 Progress Energy [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Sep. 30, 2013 Progress Energy [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Dec. 31, 2012 Progress Energy [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Progress [Member]		Dec. 31, 2012 Duke Energy Progress [Member]		Sep. 30, 2013 Duke Energy Progress [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Progress [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Level 2 [Member]		Dec. 31, 2012 Duke Energy Progress [Member] Level 2 [Member]		Dec. 31, 2012 Duke Energy Progress [Member] Level 3 [Member]		Sep. 30, 2013 Duke Energy Progress [Member] NDTF [Member] Equity Securities [Member]	Dec. 31, 2012 Duke Energy Progress [Member] NDTF [Member] Equity Securities [Member]	Sep. 30, 2013 Duke Energy Progress [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Progress [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member]	Dec. 31, 2012 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member]	Sep. 30, 2013 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Dec. 31, 2012 Duke Energy Progress [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Other Classification [Member] Debt Securities [Member]		Dec. 31, 2012 Duke Energy Progress [Member] Other Classification [Member] Debt Securities [Member]		Sep. 30, 2013 Duke Energy Progress [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Dec. 31, 2012 Duke Energy Progress [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Sep. 30, 2013 Duke Energy Florida [Member]		Dec. 31, 2012 Duke Energy Florida [Member]		Sep. 30, 2013 Duke Energy Florida [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Florida [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Level 2 [Member]		Dec. 31, 2012 Duke Energy Florida [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member]	Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Equity Securities [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member]	Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2012 Duke Energy Florida [Member] NDTF [Member] Debt Securities [Member] Level 2 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member]		Sep. 30, 2012 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member]		Sep. 30, 2013 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Sep. 30, 2012 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member] Level 1 [Member]		Sep. 30, 2013 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Sep. 30, 2012 Duke Energy Florida [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Ohio [Member]		Dec. 31, 2012 Duke Energy Ohio [Member]		Sep. 30, 2013 Duke Energy Ohio [Member] Level 1 [Member]		Dec. 31, 2012 Duke Energy Ohio [Member] Level 1 [Member]		Sep. 30, 2013 Duke Energy Ohio [Member] Level 2 [Member]		Dec. 31, 2012 Duke Energy Ohio [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Ohio [Member] Level 3 [Member]		Dec. 31, 2012 Duke Energy Ohio [Member] Level 3 [Member]		Sep. 30, 2013 Duke Energy Indiana [Member]		Dec. 31, 2012 Duke Energy Indiana [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Level 1 [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Level 1 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Level 2 [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Level 2 [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Level 3 [Member]		Dec. 31, 2012 Duke Energy Indiana [Member] Level 3 [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Other Classification [Member] Equity Securities [Member]		Dec. 31, 2012 Duke Energy Indiana [Member] Other Classification [Member] Equity Securities [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Other Classification [Member] Equity Securities [Member] Level 1 [Member]		Dec. 31, 2012 Duke Energy Indiana [Member] Other Classification [Member] Equity Securities [Member] Level 1 [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Other Classification [Member] Debt Securities [Member]		Dec. 31, 2012 Duke Energy Indiana [Member] Other Classification [Member] Debt Securities [Member]		Sep. 30, 2013 Duke Energy Indiana [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]		Dec. 31, 2012 Duke Energy Indiana [Member] Other Classification [Member] Debt Securities [Member] Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments																	$ 25	[1]	$ 29	[1]	$ 25	[1]	$ 29	[1]	$ 3,280	$ 2,837	$ 3,199	$ 2,762	$ 59	$ 54	$ 22	$ 21	$ 1,525	$ 1,405	$ 392	$ 317	$ 1,083	$ 1,040	$ 50	$ 48	$ 93	[2]	$ 72	[2]	$ 83	[2]	$ 63	[2]	$ 10	[2]	$ 9	[2]	$ 414	[3]	$ 602	[3]	$ 57	[3]	$ 40	[3]	$ 357	[3]	$ 562	[3]													$ 3	[4]	$ 3	[4]	$ 3	[4]	$ 3	[4]	$ 1,790	$ 1,592	$ 1,715	$ 1,523	$ 53	$ 48	$ 22	$ 21	$ 883	$ 762	$ 220	$ 155	$ 613	$ 559	$ 50	$ 48													$ 1,489	$ 1,245	$ 1,483	$ 1,239	$ 6	$ 6	$ 642	$ 643	$ 172	$ 162	$ 470	$ 481	$ 55	[5]	$ 57	[5]	$ 19	[5]	$ 17	[5]	$ 36	[5]	$ 40	[5]													$ 985	$ 811	$ 985	$ 811	$ 440	$ 448	$ 112	$ 119	$ 328	$ 329	$ 2	[5]	$ 3	[5]	$ 2	[5]	$ 3	[5]											$ 505	$ 435	$ 499	$ 429	$ 6	$ 6	$ 202	$ 194	$ 60	$ 43	$ 142	$ 151	$ 39	[6]	$ 43	[6]	$ 2	[6]	$ 3	[6]	$ 37	[6]	$ 40	[6]																														$ 60	[1]	$ 49	[1]	$ 60	[1]	$ 49	[1]	$ 28	[1]	$ 29	[1]	$ 28	[1]	$ 29	[1]
Derivative assets	127	[2]	103	[2]	32	[2]	18	[2]	22	[2]	22	[2]	73	[2]	63	[2]																																																																																							11	[7]					11	[7]																													2	[7]					2	[7]																							9						9																										70	[8]	59	[8]	49	[8]	48	[8]			2	[8]	21	[8]	9	[8]	14	[9]	10	[9]						14	[9]	10	[9]
Total assets	5,464		5,048		3,763		3,200		1,531		1,687		170		161																																																		2,676		2,357		1,935	1,678	666	607	75		72																										2,186		1,956		1,674	1,418	512		538																												1,427		1,264		1,099	933	328		331																						746		681		561	475	185		206																																										102		88		60	49	28	29		14		10
Derivative liabilities	(473)	[10]	(756)	[10]	(15)	[10]	(17)	[10]	(347)	[10]	(591)	[10]	(111)	[10]	(148)	[10]																																																	(4)	[11]	(12)	[11]					(4)	[11]	(12)	[11]																									(282)	[12]	(440)	[12]			(282)	[12]	(402)	[12]	(38)	[12]																									(107)	[12]	(166)	[12]			(107)	[12]	(128)	[12]	(38)	[12]																			(171)	[13]	(270)	[13]			(171)	[13]	(270)	[13]																									(46)	[12]	(38)	[12]	(14)	[12]	(15)	[12]	(5)	[12]	(8)	[12]	(27)	[12]	(15)	[12]			(63)	[10]				(63)	[10]
Net assets	$ 4,991		$ 4,292		$ 3,748		$ 3,183		$ 1,184		$ 1,096		$ 59		$ 13																																																		$ 2,672		$ 2,345		$ 1,935	$ 1,678	$ 666	$ 607	$ 71		$ 60																										$ 1,904		$ 1,516		$ 1,674	$ 1,418	$ 230		$ 136		$ (38)																										$ 1,320		$ 1,098		$ 1,099	$ 933	$ 221		$ 203		$ (38)																				$ 575		$ 411		$ 561	$ 475	$ 14		$ (64)																										$ 24		$ 21		$ 35		$ 33		$ (5)		$ (6)		$ (6)		$ (6)		$ 102		$ 25		$ 60	$ 49	$ 28	$ (34)		$ 14		$ 10

[1] Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.

[2] Included in Other within Current Assets and Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.

[3] Included in Other within Investments and Other Assets and Short-term Investments on the Condensed Consolidated Balance Sheets.

[4] Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.

[5] Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[6] Included in Other within Investments and Other Assets in the Condensed Balance Sheets.

[7] Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[8] Included in Other within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[9] Included in Other within Current Assets on the Condensed Consolidated Balance Sheets.

[10] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.

[11] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.

[12] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.

[13] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Balance Sheets