Severance (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2015 Employees	Dec. 31, 2013 USD ($)
2015 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of eligible employees \| Employees	900
Duke Energy Florida [Member] \| Crystal River Unit 3 2013 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Deferred severance costs \| $		$ 26

The deferral in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

No definition available.

Name:	duk_DeferredSeveranceCosts
Namespace Prefix:	duk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration