Employee Benefit Plans (Sensitivity to Changes in Assumed Health Care Cost Trend Rates) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	$ 9
Effect on total service and interest costs - 1 Percentage Point Decrease	(7)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	164
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(133)
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	11
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(10)
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	8
Effect on total service and interest costs - 1 Percentage Point Decrease	(6)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	133
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(106)
Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	4
Effect on total service and interest costs - 1 Percentage Point Decrease	(3)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	72
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(57)
Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	3
Effect on total service and interest costs - 1 Percentage Point Decrease	(2)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	49
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(39)
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	3
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	(3)
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect on total service and interest costs - 1 Percentage Point Increase	1
Effect on total service and interest costs - 1 Percentage Point Decrease	(1)
Effect on post-retirement benefit obligation - 1 Percentage Point Increase	8
Effect on post-retirement benefit obligation - 1 Percentage Point Decrease	$ (7)