Risk Management, Derivative Instruments And Hedging Activities (Schedule Of Offsetting Assets and Liabilities: Derivatives and collateral posted) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	$ 309		$ 264
Derivative assets	75	[1]	103	[1]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	845		917
Derivative liabilities	611	[2]	756	[2]
Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	182		127
Derivative asset, fair value, gross liability	157		114
Derivative asset, not subject to master netting arrangement	21		22
Other Current Assets [Member] | Gross Amounts Recognized [Member]
Derivative Assets Subject to Master Netting
Derivative assets	203		149
Other Current Assets [Member] | Gross Amounts Offset [Member]
Derivative Assets Subject to Master Netting
Derivative assets	157		114
Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	25		13
Derivative asset, not subject to master netting arrangement	21		22
Derivative assets	46	[3]	35	[3]
Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	91		96
Derivative asset, fair value, gross liability	75		54
Derivative asset, not subject to master netting arrangement	15		19
Other Noncurrent Assets [Member] | Gross Amounts Recognized [Member]
Derivative Assets Subject to Master Netting
Derivative assets	106		115
Other Noncurrent Assets [Member] | Gross Amounts Offset [Member]
Derivative Assets Subject to Master Netting
Derivative assets	75		54
Other Noncurrent Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	16		42
Derivative asset, not subject to master netting arrangement	15		19
Derivative assets	31	[4]	61	[4]
Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	350		402
Derivative liability, fair value, gross asset	222		151
Derivative liability, not subject to master netting arrangement	159		166
Other Current Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	509		568
Other Current Liabilities [Member] | Gross Amounts Offset [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	222		151
Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	128		251
Derivative liability, not subject to master netting arrangement	159		166
Derivative liabilities	287	[5]	417	[5]
Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	295		295
Derivative liability, fair value, gross asset	118		90
Derivative liability, not subject to master netting arrangement	41		54
Other Noncurrent Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	336		349
Other Noncurrent Liabilities [Member] | Gross Amounts Offset [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	118		90
Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	177		205
Derivative liability, not subject to master netting arrangement	41		54
Derivative liabilities	218	[6]	259	[6]
Duke Energy Carolinas [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	5		12
Derivative liabilities	5	[7]	12	[7]
Duke Energy Carolinas [Member] | Other Current Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	2		6
Duke Energy Carolinas [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	2	[5]	6	[5]
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	3		6
Duke Energy Carolinas [Member] | Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	3	[6]	6	[6]
Progress Energy [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	47		11
Derivative assets	15	[8]	11	[8]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	301		440
Derivative liabilities	269	[9]	440	[9]
Progress Energy [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	33		3
Derivative asset, fair value, gross liability	21
Progress Energy [Member] | Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	12	[3]	3	[3]
Progress Energy [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	14		8
Derivative asset, fair value, gross liability	12
Progress Energy [Member] | Other Noncurrent Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	2	[4]	8	[4]
Progress Energy [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	141		244
Derivative liability, fair value, gross asset	34		22
Progress Energy [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	107	[5]	222	[5]
Progress Energy [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	156		192
Derivative liability, fair value, gross asset	34		36
Derivative liability, not subject to master netting arrangement	4		4
Progress Energy [Member] | Other Noncurrent Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	160		196
Progress Energy [Member] | Other Noncurrent Liabilities [Member] | Gross Amounts Offset [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	34		36
Progress Energy [Member] | Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	122		156
Derivative liability, not subject to master netting arrangement	4		4
Derivative liabilities	126	[6]	160	[6]
Duke Energy Progress [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	14		2
Derivative assets	5	[8]	2	[8]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	108		166
Derivative liabilities	98	[10]	166	[10]
Duke Energy Progress [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	12		1
Derivative asset, fair value, gross liability	8
Duke Energy Progress [Member] | Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	4	[3]	1	[3]
Duke Energy Progress [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	2		1
Derivative asset, fair value, gross liability	2
Duke Energy Progress [Member] | Other Noncurrent Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	0	[4]	1	[4]
Duke Energy Progress [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	53		97
Derivative liability, fair value, gross asset	8		2
Duke Energy Progress [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	45	[5]	95	[5]
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	55		69
Derivative liability, fair value, gross asset	5		7
Duke Energy Progress [Member] | Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	50	[6]	62	[6]
Duke Energy Florida [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	33		9
Derivative assets	10	[11]	9	[11]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	190		270
Derivative liabilities	167	[12]	270	[12]
Duke Energy Florida [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	21		2
Derivative asset, fair value, gross liability	13
Duke Energy Florida [Member] | Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	8	[13]	2	[13]
Duke Energy Florida [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	12		7
Derivative asset, fair value, gross liability	10
Duke Energy Florida [Member] | Other Noncurrent Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	2	[14]	7	[14]
Duke Energy Florida [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	89		147
Derivative liability, fair value, gross asset	26		20
Duke Energy Florida [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	63	[15]	127	[15]
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	101		123
Derivative liability, fair value, gross asset	29		29
Duke Energy Florida [Member] | Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	72	[16]	94	[16]
Duke Energy Ohio [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	244		220
Derivative assets	19	[17]	59	[17]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	319		199
Derivative liabilities	94	[9]	38	[9]
Duke Energy Ohio [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	172		137
Derivative asset, fair value, gross liability	163		110
Derivative asset, not subject to master netting arrangement	2		2
Duke Energy Ohio [Member] | Other Current Assets [Member] | Gross Amounts Recognized [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet			27
Derivative assets	174		139
Duke Energy Ohio [Member] | Other Current Assets [Member] | Gross Amounts Offset [Member]
Derivative Assets Subject to Master Netting
Derivative assets	163		110
Duke Energy Ohio [Member] | Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	9
Derivative asset, not subject to master netting arrangement	2		2
Derivative assets	11	[3]	29	[3]
Duke Energy Ohio [Member] | Other Noncurrent Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	70		81
Derivative asset, fair value, gross liability	63		51
Duke Energy Ohio [Member] | Other Noncurrent Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	7	[4]	30	[4]
Duke Energy Ohio [Member] | Other Current Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	214		136
Derivative liability, fair value, gross asset	209		125
Derivative liability, not subject to master netting arrangement	1		1
Duke Energy Ohio [Member] | Other Current Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	215		137
Duke Energy Ohio [Member] | Other Current Liabilities [Member] | Gross Amounts Offset [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	209		125
Duke Energy Ohio [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	5		11
Derivative liability, not subject to master netting arrangement	1		1
Derivative liabilities	6	[5]	12	[5]
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	98		55
Derivative liability, fair value, gross asset	90		51
Derivative liability, not subject to master netting arrangement	6		7
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	104		62
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member] | Gross Amounts Offset [Member]
Derivative Liabilities Subject to Master Netting
Derivative liabilities	90		51
Duke Energy Ohio [Member] | Other Noncurrent Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, net amounts included on the Consolidated Balance Sheets	8		4
Derivative liability, not subject to master netting arrangement	6		7
Derivative liabilities	14	[6]	11	[6]
Duke Energy Indiana [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	5		10
Derivative assets	5	[18]	10	[18]
Derivative Liabilities Subject to Master Netting
Derivative liability, fair value, gross liability	55		63
Derivative liabilities	55	[2]	63	[2]
Duke Energy Indiana [Member] | Other Current Assets [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, gross asset	5		10
Duke Energy Indiana [Member] | Other Current Assets [Member] | Net Amounts On Balance Sheet [Member]
Derivative Assets Subject to Master Netting
Derivative asset, fair value, net amounts included on the Condensed Balance Sheet	5	[3]	10	[3]
Duke Energy Indiana [Member] | Other Current Liabilities [Member] | Gross Amounts Recognized [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	55		63
Duke Energy Indiana [Member] | Other Current Liabilities [Member] | Net Amounts On Balance Sheet [Member]
Derivative Liabilities Subject to Master Netting
Derivative liability, not subject to master netting arrangement	$ 55	[5]	$ 63	[5]

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

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

[3] Included in Other within Current Assets on the Condensed Consolidated Balance Sheet.

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

[5] Included in Other within Current Liabilities on the Condensed Consolidated Balance Sheet.

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

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

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

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

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

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

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

[13] Included in Other within Current Assets on the Condensed Balance Sheet.

[14] Included in Other within Investments and Other Assets on the Condensed Balance Sheet.

[15] Included in Other within Current Liabilities on the Condensed Balance Sheet.

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

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

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