Regulatory Matters (Schedule of Regulatory Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 12,250	$ 12,157
Regulatory assets, current	877	1,115
Regulatory assets, noncurrent	11,373	11,042
Regulatory liabilities	6,655	6,397
Regulatory liabilities - current	400	204
Regulatory liabilities, noncurrent	6,255	6,193
Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	5,329	5,221
Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	71	166
Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	150	150
Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	288	379
Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	311	37
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	506	444
Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,555	1,992
Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	838	1,025
Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,151	2,015
Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	509	1,659
Debt Fair Value Adjustment [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,191	1,305
Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,075	1,144
Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,237
Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	571	628
Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	340	330
Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	68	76
Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	192	213
Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	151	246
Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	245	296
Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	383	494
Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	32	55
Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	72	70
Manufactured Gas Plant Environmental Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	104	115
NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21
East Bend deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	16
Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	499	494
Duke Energy Carolinas [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	3,071	2,864
Regulatory assets, current	305	399
Regulatory assets, noncurrent	2,766	2,465
Regulatory liabilities	2,841	2,744
Regulatory liabilities - current	39	34
Regulatory liabilities, noncurrent	2,802	2,710
Duke Energy Carolinas [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	2,413	2,420
Duke Energy Carolinas [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	24	25
Duke Energy Carolinas [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	68	76
Duke Energy Carolinas [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	55	6
Duke Energy Carolinas [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	281	217
Duke Energy Carolinas [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,120	840
Duke Energy Carolinas [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	104	67
Duke Energy Carolinas [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	479	412
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	49	58
Duke Energy Carolinas [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	564	614
Duke Energy Carolinas [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	127	103
Duke Energy Carolinas [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	80	106
Duke Energy Carolinas [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	79	86
Duke Energy Carolinas [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21	50
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	107	141
Duke Energy Carolinas [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	97	124
Duke Energy Carolinas [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	244	263
Progress Energy [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5,797	5,899
Regulatory assets, current	362	491
Regulatory assets, noncurrent	5,435	5,408
Regulatory liabilities	2,673	2,485
Regulatory liabilities - current	286	106
Regulatory liabilities, noncurrent	2,387	2,379
Progress Energy [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	2,078	1,975
Progress Energy [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		70
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	51	121
Progress Energy [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	255	23
Progress Energy [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	164	171
Progress Energy [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,394	1,152
Progress Energy [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	487	730
Progress Energy [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	807	812
Progress Energy [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	409	1,545
Progress Energy [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	318	354
Progress Energy [Member] | Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,237
Progress Energy [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	410	490
Progress Energy [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	250	203
Progress Energy [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	46
Progress Energy [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	129	182
Progress Energy [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	138	155
Progress Energy [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	121
Progress Energy [Member] | NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21
Progress Energy [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	121	109
Duke Energy Progress [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,974	2,962
Regulatory assets, current	264	287
Regulatory assets, noncurrent	2,710	2,675
Regulatory liabilities	1,963	1,903
Regulatory liabilities - current	85	71
Regulatory liabilities, noncurrent	1,878	1,832
Duke Energy Progress [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1,725	1,692
Duke Energy Progress [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	25	61
Duke Energy Progress [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	58	23
Duke Energy Progress [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	155	127
Duke Energy Progress [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,386	1,152
Duke Energy Progress [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	195	432
Duke Energy Progress [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	366	354
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	179	152
Duke Energy Progress [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	106	141
Duke Energy Progress [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	171	217
Duke Energy Progress [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	237	193
Duke Energy Progress [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	46
Duke Energy Progress [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	93	138
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	62	43
Duke Energy Progress [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	38	28
Duke Energy Progress [Member] | NCEMPA deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	21
Duke Energy Progress [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	82	66
Duke Energy Florida [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	2,823	2,936
Regulatory assets, current	98	203
Regulatory assets, noncurrent	2,725	2,733
Regulatory liabilities	709	582
Regulatory liabilities - current	200	35
Regulatory liabilities, noncurrent	509	547
Duke Energy Florida [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	353	283
Duke Energy Florida [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities		70
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	26	60
Duke Energy Florida [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	197
Duke Energy Florida [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	8	44
Duke Energy Florida [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	8
Duke Energy Florida [Member] | Asset retirement obligations - nuclear and other [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	292	298
Duke Energy Florida [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	441	458
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	230	1,393
Duke Energy Florida [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	212	213
Duke Energy Florida [Member] | Nuclear asset securitizable balance, net [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1,237
Duke Energy Florida [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	239	273
Duke Energy Florida [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	13	10
Duke Energy Florida [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	36	44
Duke Energy Florida [Member] | Nuclear Deferral [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	76	112
Duke Energy Florida [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets		93
Duke Energy Florida [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	39	42
Duke Energy Ohio [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	533	561
Regulatory assets, current	36	49
Regulatory assets, noncurrent	497	512
Regulatory liabilities	257	251
Regulatory liabilities - current	12	10
Regulatory liabilities, noncurrent	245	241
Duke Energy Ohio [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	222	222
Duke Energy Ohio [Member] | Storm Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1
Duke Energy Ohio [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	21	19
Duke Energy Ohio [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	1
Duke Energy Ohio [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	12	10
Duke Energy Ohio [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	4
Duke Energy Ohio [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	139	132
Duke Energy Ohio [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	55	64
Duke Energy Ohio [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	7	7
Duke Energy Ohio [Member] | Demand Side Management And Energy Efficiency [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	10	21
Duke Energy Ohio [Member] | Grid Modernization [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	68	76
Duke Energy Ohio [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	5	6
Duke Energy Ohio [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	1	9
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] | Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	0
Duke Energy Ohio [Member] | Transmission Expansion Obligation [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	72	74
Duke Energy Ohio [Member] | Manufactured Gas Plant Environmental Reserve [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	104	115
Duke Energy Ohio [Member] | East Bend deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	16
Duke Energy Ohio [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	31	36
Duke Energy Indiana [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	818	778
Regulatory assets, current	102	93
Regulatory assets, noncurrent	716	685
Regulatory liabilities	816	850
Regulatory liabilities - current	62	54
Regulatory liabilities, noncurrent	754	796
Duke Energy Indiana [Member] | Costs of Removal [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	616	613
Duke Energy Indiana [Member] | Amounts To Be Refunded to Customers [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	71	96
Duke Energy Indiana [Member] | Accrued Pension And Other Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory liabilities	83	91
Duke Energy Indiana [Member] | Deferred Fuel and Purchased Power [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	46	42
Duke Energy Indiana [Member] | Asset retirement obligations - coal ash [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	37
Duke Energy Indiana [Member] | Accrued Pension And Post Retirement [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	220	217
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	51	56
Duke Energy Indiana [Member] | Net Regulatory Asset Related To Income Taxes [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	120	111
Duke Energy Indiana [Member] | Hedge Cost and Other Deferrals [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	27	28
Duke Energy Indiana [Member] | Vacation Accrual [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	10	12
Duke Energy Indiana [Member] | Deferred Fuel and Purchased Power [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets		5
Duke Energy Indiana [Member] | Post-In-Service Carrying Costs And Deferred Operating Expense [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	227	228
Duke Energy Indiana [Member] | Gasification Services Agreement Buyout Costs [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	32	55
Duke Energy Indiana [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets Liabilities [Line Items]
Regulatory assets	$ 94	$ 66