Asset Retirement Obligations Asset Retirement Obligations (Asset Retirement Costs) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	$ 71,759	$ 70,046
Regulatory assets	11,564	11,042
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	24,965	24,672
Regulatory assets	2,631	2,465
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	25,804	25,144
Regulatory assets	5,813	5,408
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	15,571	15,186
Regulatory assets	3,119	2,675
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	5,117	4,937
Regulatory assets	506	512
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	9,323	8,815
Regulatory assets	707	$ 685
Asset Retirement Obligation Costs [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	535
Regulatory assets	448
Asset Retirement Obligation Costs [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	178
Asset Retirement Obligation Costs [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	270
Asset Retirement Obligation Costs [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Regulatory assets	270
Asset Retirement Obligation Costs [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	116
Asset Retirement Obligation Costs [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	$ 418