Regulatory Matters (Schedule of Regulatory Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 12,157	$ 10,086
Regulatory assets - current	1,115	895
Regulatory assets, noncurrent	11,042	9,191
Regulatory liabilities	6,397	6,265
Regulatory liabilities - current	204	316
Regulatory liabilities - noncurrent	6,193	5,949
Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	5,221	5,308
Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	166	151
Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	150	145
Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	379	138
Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	37	177
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	444	346
Asset Retirement Obligations Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	3,017	1,608
Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,015	1,723
Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,659	1,748
Debt Fair Value Adjustment [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,305	1,338
Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,144	1,115
Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	628	450
Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	330	306
Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	76	65
Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	213	210
Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	246	94
Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	296	262
Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	494	459
Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	55	75
Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	70	70
Manufactured Gas Plant Environmental Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	115	90
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	494	473
Duke Energy Carolinas [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,864	1,822
Regulatory assets - current	399	295
Regulatory assets, noncurrent	2,465	1,527
Regulatory liabilities	2,744	2,641
Regulatory liabilities - current	34	65
Regulatory liabilities - noncurrent	2,710	2,576
Duke Energy Carolinas [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	2,420	2,423
Duke Energy Carolinas [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	25	20
Duke Energy Carolinas [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	76
Duke Energy Carolinas [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	6	45
Duke Energy Carolinas [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	217	153
Duke Energy Carolinas [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	907	123
Duke Energy Carolinas [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	412	347
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	58	68
Duke Energy Carolinas [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	614	555
Duke Energy Carolinas [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	103	98
Duke Energy Carolinas [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	106	140
Duke Energy Carolinas [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	86	82
Duke Energy Carolinas [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	50
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	141	40
Duke Energy Carolinas [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	124	150
Duke Energy Carolinas [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	263	219
Progress Energy [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5,899	4,508
Regulatory assets - current	491	353
Regulatory assets, noncurrent	5,408	4,155
Regulatory liabilities	2,485	2,499
Regulatory liabilities - current	106	207
Regulatory liabilities - noncurrent	2,379	2,292
Progress Energy [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1,975	2,008
Progress Energy [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	70	120
Progress Energy [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	125	125
Progress Energy [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	121
Progress Energy [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	23	132
Progress Energy [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	171	114
Progress Energy [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,882	786
Progress Energy [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	812	750
Progress Energy [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,545	1,619
Progress Energy [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	354	331
Progress Energy [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	490	318
Progress Energy [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	203	152
Progress Energy [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	46	55
Progress Energy [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	182	37
Progress Energy [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	155	222
Progress Energy [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	121	137
Progress Energy [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	109	101
Duke Energy Progress [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,962	1,511
Regulatory assets - current	287	127
Regulatory assets, noncurrent	2,675	1,384
Regulatory liabilities	1,903	1,736
Regulatory liabilities - current	71	63
Regulatory liabilities - noncurrent	1,832	1,673
Duke Energy Progress [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1,692	1,637
Duke Energy Progress [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	61
Duke Energy Progress [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	23
Duke Energy Progress [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	127	99
Duke Energy Progress [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,584	389
Duke Energy Progress [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	354	269
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	152	241
Duke Energy Progress [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	141	113
Duke Energy Progress [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	217	165
Duke Energy Progress [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	193	140
Duke Energy Progress [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	46	50
Duke Energy Progress [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	138	6
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	43	77
Duke Energy Progress [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	28	19
Duke Energy Progress [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	66	42
Duke Energy Florida [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,936	2,950
Regulatory assets - current	203	221
Regulatory assets, noncurrent	2,733	2,729
Regulatory liabilities	582	762
Regulatory liabilities - current	35	144
Regulatory liabilities - noncurrent	547	618
Duke Energy Florida [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	283	371
Duke Energy Florida [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	70	120
Duke Energy Florida [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	125	125
Duke Energy Florida [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	60
Duke Energy Florida [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		132
Duke Energy Florida [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	44	14
Duke Energy Florida [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	298	397
Duke Energy Florida [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	458	438
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,393	1,378
Duke Energy Florida [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	213	218
Duke Energy Florida [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	273	153
Duke Energy Florida [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	10	12
Duke Energy Florida [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	44	31
Duke Energy Florida [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	112	145
Duke Energy Florida [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	93	118
Duke Energy Florida [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	42	60
Duke Energy Ohio [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	561	528
Regulatory assets - current	49	57
Regulatory assets, noncurrent	512	471
Regulatory liabilities	251	289
Regulatory liabilities - current	10	27
Regulatory liabilities - noncurrent	241	262
Duke Energy Ohio [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	222	241
Duke Energy Ohio [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	19	21
Duke Energy Ohio [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	10	27
Duke Energy Ohio [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	132	120
Duke Energy Ohio [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	64	72
Duke Energy Ohio [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	7	5
Duke Energy Ohio [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21	14
Duke Energy Ohio [Member] | Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	76	65
Duke Energy Ohio [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	6	7
Duke Energy Ohio [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	9	14
Duke Energy Ohio [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21	21
Duke Energy Ohio [Member] | Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	74	74
Duke Energy Ohio [Member] | Manufactured Gas Plant Environmental Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	115	90
Duke Energy Ohio [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	36	46
Duke Energy Indiana [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	778	835
Regulatory assets - current	93	118
Regulatory assets, noncurrent	685	717
Regulatory liabilities	850	798
Regulatory liabilities - current	54	16
Regulatory liabilities - noncurrent	796	782
Duke Energy Indiana [Member] | Removal Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	613	645
Duke Energy Indiana [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	96	31
Duke Energy Indiana [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	91	77
Duke Energy Indiana [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	8
Duke Energy Indiana [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	42	45
Duke Energy Indiana [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	217	219
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	56	61
Duke Energy Indiana [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	111	157
Duke Energy Indiana [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	28	29
Duke Energy Indiana [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	12	13
Duke Energy Indiana [Member] | Deferred Fuel [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5	43
Duke Energy Indiana [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	228	151
Duke Energy Indiana [Member] | Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	55	75
Duke Energy Indiana [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 66	$ 87