Severance (Narrative)(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012		Sep. 30, 2012
Number of employees accepted the Voluntary program			$ 1,100
Severance Costs	146	[1]	146	[1]
Duke Energy Carolinas [Member]
Severance Costs	48		48
Duke Energy Ohio [Member]
Number of eligible employees			330
Severance Costs	15		15
Duke Energy Indiana [Member]
Severance Costs	13		13
Minimum [Member]
Severance Costs			80
Maximum [Member]
Severance Costs			$ 110

[1] Includes $16 million of COBRA and healthcare reimbursement expenses and $14 million of accelerated stock award expense.