Asset Retirement Obligations Asset Retirement Obligations (Asset Retirement Costs) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	$ 73,776	$ 70,046
Regulatory assets	11,290	11,042
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	25,208	24,672
Regulatory assets	2,741	2,465
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	27,538	25,144
Regulatory assets	5,535	5,408
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	17,172	15,186
Regulatory assets	2,816	2,675
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	5,175	4,937
Regulatory assets	495	512
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Property, Plant and Equipment, Net	9,340	8,815
Regulatory assets	645	$ 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