Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 724	$ 831
Duke Energy Carolinas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	296	313
Progress Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	151	161
Duke Energy Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	84	102
Duke Energy Florida [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	67	59
Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	2	2
Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	27	32
Piedmont Natural Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	38	77
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	69	97
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 106	$ 123