Asset Retirement Obligations Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 10,264	$ 8,466	$ 4,958
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,072
Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	4,958
Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	234
Duke Energy Carolinas [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,918	3,428	1,594
Duke Energy Carolinas [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	1,730
Duke Energy Carolinas [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,161
Duke Energy Carolinas [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	27
Progress Energy [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	5,369	4,711	2,570
Progress Energy [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	3,093
Progress Energy [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,196
Progress Energy [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	80
Duke Energy Progress [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	4,567	3,905	1,737
Duke Energy Progress [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,349
Duke Energy Progress [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	2,188
Duke Energy Progress [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	30
Duke Energy Florida [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	802	806	833
Duke Energy Florida [Member] | Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	744
Duke Energy Florida [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	7
Duke Energy Florida [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	51
Duke Energy Ohio [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	125	27	28
Duke Energy Ohio [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	94
Duke Energy Ohio [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	31
Duke Energy Indiana [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	525	$ 32	$ 30
Duke Energy Indiana [Member] | Closure of Ash Basins [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	507
Duke Energy Indiana [Member] | Other [Member]
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$ 18