Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Other Assets and Liabilities)(Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Other current receivables	$ 703	$ 791
Collateral assets	30	209
Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	621	638
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	142	129
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	213	216
Collateral liabilities	141	128
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	151	129
Collateral assets	30	23
Progress Energy [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	129	718
Progress Energy [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	373	360
Derivative liabilities	201	271
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	87	43
Duke Energy Progress [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	111	272
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	141	135
Accrued compensation	108	116
Derivative liabilities	76	108
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	60	84
Collateral assets	30	23
Duke Energy Florida [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable		177
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	232	225
Derivative liabilities	125	163
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	66	93
Collateral assets		186
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	59	40
Other current receivables	33	39
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued litigation reserve	80
Collateral liabilities	48	42
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Other current receivables	96	87
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable		98
Duke Energy Indiana [Member] | Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Collateral liabilities	$ 44	$ 43