Severance (Narrative)(Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 2011 Severance Plan [Member] Employees	Dec. 31, 2010 2010 Severance Plan [Member] Employees	Dec. 31, 2012 Duke Energy Ohio Union 2012 Severance Plan [Member] Employees	Dec. 31, 2013 Crystal River Unit 3 2013 Severance Plan [Member] Employees	Dec. 31, 2012 Minimum [Member] 2011 Severance Plan [Member]	Dec. 31, 2012 Maximum [Member] 2011 Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees that accepted the termination benefits	1,100	900	75
Estimated cash reductions					$ 30	$ 60
Number of eligible employees				600