Related Party Transactions (Other Revenue and Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 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	$ 235	[1]	$ 254	[1]	$ 478	[1]	$ 489	[1]
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	6	[2]	6	[2]	11	[2]	11	[2]
Duke Energy Carolinas [Member] | Joint Dispatch Agreement Revenue [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	24	[3]			77	[3]
Duke Energy Carolinas [Member] | Joint Dispatch Agreement Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	22	[3]			32	[3]
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	111	[1]			273	[1]
Related party transaction, other revenues from transactions with related party	22	[4]			50	[4]
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	9	[2]			17	[2]
Progress Energy [Member] | Joint Dispatch Agreement Revenue [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	22	[3]			32	[3]
Progress Energy [Member] | Joint Dispatch Agreement Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	24	[3]			77	[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	66	[1]	59	[1]	162	[1]	111	[1]
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	[2]			10	[2]
Duke Energy Progress [Member] | Joint Dispatch Agreement Revenue [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	22	[3]			32	[3]
Duke Energy Progress [Member] | Joint Dispatch Agreement Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	24	[3]			77	[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	45	[1]	45	[1]	111	[1]	84	[1]
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	[2]			7	[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	85	[1]	86	[1]	172	[1]	176	[1]
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	4	[2]	3	[2]	8	[2]	7	[2]
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	101	[1]	98	[1]	200	[1]	199	[1]
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 3	[2]	$ 2	[2]	$ 5	[2]	$ 4	[2]

[1] The Subsidiary Registrants are charged their proportionate share of corporate governance and other costs by unconsolidated affiliates that 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 which allowed 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.