Asset Retirement Obligations Asset Retirement Obligations (ARO by Category) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	$ 10,830	$ 10,264
Asset Retirement Obligation, Current	539
Asset Retirement Obligations, Noncurrent	10,291	10,264
Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	3,925	3,918
Asset Retirement Obligation, Current	303
Asset Retirement Obligations, Noncurrent	3,622	3,918
Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,657	5,369
Asset Retirement Obligation, Current	236
Asset Retirement Obligations, Noncurrent	5,421	5,369
Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	4,859	4,567
Asset Retirement Obligation, Current	236
Asset Retirement Obligations, Noncurrent	4,623	4,567
Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	798	802
Asset Retirement Obligations, Noncurrent	798	802
Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	108	125
Asset Retirement Obligations, Noncurrent	108	125
Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	847	525
Asset Retirement Obligations, Noncurrent	847	$ 525
Decommissioning of Nuclear Power Facilities [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,163
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	1,808
Decommissioning of Nuclear Power Facilities [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	3,153
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,428
Decommissioning of Nuclear Power Facilities [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	725
Closure of Ash Impoundments [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	5,411
Closure of Ash Impoundments [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,089
Closure of Ash Impoundments [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,418
Closure of Ash Impoundments [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	2,398
Closure of Ash Impoundments [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	20
Closure of Ash Impoundments [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	77
Closure of Ash Impoundments [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	828
Other [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	256
Other [Member] | Duke Energy Carolinas [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	28
Other [Member] | Progress Energy [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	86
Other [Member] | Duke Energy Progress [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	33
Other [Member] | Duke Energy Florida [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	53
Other [Member] | Duke Energy Ohio [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	31
Other [Member] | Duke Energy Indiana [Member]
Asset Retirement Obligations [Line Items]
Asset Retirement Obligation	$ 19