Related Party Transactions (Other Revenue and Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 236	[1]	$ 309	[1]	$ 714	[1]	$ 798	[1]
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	[2]	5	[2]	16	[2]	16	[2]
Duke Energy Carolinas [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	24	[3]	8	[3]	101	[3]	8	[3]
Related party transaction, expenses from transactions with related party	39	[3]	37	[3]	71	[3]	37	[3]
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	24	[4]	30	[4]	74	[4]	30	[4]
Related party transaction, expenses from transactions with related party	54	[1]	31	[1]	327	[1]	31	[1]
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	[2]	7	[2]	26	[2]	7	[2]
Progress Energy [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	39	[3]	37	[3]	71	[3]	37	[3]
Related party transaction, expenses from transactions with related party	24	[3]	8	[3]	101	[3]	8	[3]
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	33	[1]	72	[1]	195	[1]	183	[1]
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	[2]	3	[2]	15	[2]	3	[2]
Duke Energy Progress [Member] | Joint Dispatch Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	39	[3]	37	[3]	71	[3]	37	[3]
Related party transaction, expenses from transactions with related party	24	[3]	8	[3]	101	[3]	8	[3]
Duke Energy Florida [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	20	[1]	52	[1]	131	[1]	136	[1]
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	[2]	4	[2]	11	[2]	4	[2]
Duke Energy Ohio [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	89	[1]	103	[1]	261	[1]	279	[1]
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	3	[2]	4	[2]	11	[2]	11	[2]
Duke Energy Ohio [Member] | MarkTo Market Of Commodity Contracts And Sales Of Power [Member] | DECAM [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party							31
Related party transaction, expenses from transactions with related party					7
Duke Energy Indiana [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	113	[1]	118	[1]	313	[1]	317	[1]
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 5	[2]	$ 2	[2]	$ 10	[2]	$ 6	[2]

[1] The Subsidiary Registrants are charged their proportionate share of corporate governance and other costs by unconsolidated affiliates. These entities are consolidated affiliates of Duke Energy and Progress Energy. Corporate governance and other shared services costs are primarily related to human resources, employee benefits, legal and accounting fees, as well as other third party costs. These amounts are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.

[2] The Subsidiary Registrants incur expenses related to certain indemnification coverages through Bison, Duke Energy’s wholly owned captive insurance subsidiary. These expenses are recorded in Operation, maintenance and other on the Condensed Consolidated Statements of Operations and Comprehensive Income.

[3] Effective with the consummation of the merger between Duke Energy and Progress Energy, Duke Energy Carolinas and Duke Energy Progress began to participate in a JDA. The JDA allows the collective dispatch of power plants between the service territories to reduce customer rates. Revenues from the sale of power under the JDA are recorded in Operating Revenues on the Condensed Consolidated Statements of Operations and Comprehensive Income. Expenses from the purchase of power under the JDA are recorded in Fuel used in electric generation and purchased power on the Condensed Consolidated Statements of Operations and Comprehensive Income.

[4] Progress Energy charges a proportionate share of corporate governance and other costs to unconsolidated affiliates that are consolidated affiliates of Duke Energy. Corporate governance and other shared costs are primarily related to human resources, employee benefits, legal and accounting fees, as well as other third-party costs. These charges are recorded as an offset to Operation, maintenance and other in the Condensed Consolidated Statements of Operations and Comprehensive Income.