Employee Benefit Plans (Other Changes In Plan Assets And Projected Benefit Obligations Recognized In Accumulated Other Comprehensive Income And Regulatory Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	$ 11,741	$ 4,046
Regulatory liabilities	5,740	3,006
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	1,948	2,066
Regulatory liabilities	2,180	1,990
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	5,548	3,699
Regulatory liabilities	2,497	2,775
Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	1,922	1,713
Regulatory liabilities	1,548	1,545
Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	3,500	1,873
Regulatory liabilities	805	1,070
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	625	548
Regulatory liabilities	293	295
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	936	912
Regulatory liabilities	752	686
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	976	152
Deferred income tax asset	14	(10)
Actuarial gain/loss arising during the year	(2)	60
Amortization of prior year actuarial losses	(13)	(8)
Reclassification of actuarial losses to regulatory assets	(20)	8
Amortization of prior year prior service cost	(1)	(1)
Prior service credit	(7)
Net amount recognized in accumulated other comprehensive (income)/loss	(29)	49
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(111)	65
Deferred income tax asset	0	0
Actuarial gain/loss arising during the year	0	0
Amortization of prior year actuarial losses	0
Reclassification of actuarial losses to regulatory assets	0	0
Amortization of prior year prior service cost	0	0
Net amount recognized in accumulated other comprehensive (income)/loss	0	0
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(76)	298
Deferred income tax asset	0	24
Actuarial gain/loss arising during the year	3	13
Amortization of prior year actuarial losses	(2)	(8)
Reclassification of actuarial losses to regulatory assets	0	(66)
Amortization of prior year prior service cost	(1)	(1)
Net amount recognized in accumulated other comprehensive (income)/loss	0	(38)
Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(89)	98
Deferred income tax asset	0	0
Actuarial gain/loss arising during the year	0	0
Amortization of prior year actuarial losses	0	0
Reclassification of actuarial losses to regulatory assets	0	0
Amortization of prior year prior service cost	0	0
Net amount recognized in accumulated other comprehensive (income)/loss	0	0
Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	23	114
Deferred income tax asset	0	0
Actuarial gain/loss arising during the year	0	0
Amortization of prior year actuarial losses	0	0
Reclassification of actuarial losses to regulatory assets	0	0
Amortization of prior year prior service cost	0	0
Net amount recognized in accumulated other comprehensive (income)/loss	0	0
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	22	11
Deferred income tax asset	15	1
Actuarial gain/loss arising during the year		10
Amortization of prior year actuarial losses	(3)	(3)
Reclassification of actuarial losses to regulatory assets	(1)	0
Amortization of prior year prior service cost	(1)	0
Reclassification of actuarial losses to an affiliate	(48)
Net amount recognized in accumulated other comprehensive (income)/loss	(38)	8
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	17	5
Deferred income tax asset	0	0
Actuarial gain/loss arising during the year	0	0
Amortization of prior year actuarial losses	0
Reclassification of actuarial losses to regulatory assets	0	0
Amortization of prior year prior service cost	0	0
Net amount recognized in accumulated other comprehensive (income)/loss	0	0
Non Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	34	2
Regulatory liabilities, net (decrease) increase	(8)	7
Deferred income tax asset		(1)
Actuarial gain/loss arising during the year	(2)	1
Net amount recognized in accumulated other comprehensive (income)/loss	(2)
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(6)	28
Deferred income tax asset	(1)	5
Actuarial gain/loss arising during the year	3	7
Amortization of prior year actuarial losses		(2)
Reclassification of actuarial losses to an affiliate		(18)
Net amount recognized in accumulated other comprehensive (income)/loss	2	(8)
Non Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(2)	5
Non Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	1
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)		(1)
Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	484	(22)
Regulatory liabilities, net (decrease) increase	(6)	21
Deferred income tax liability	(2)	1
Amortization of prior year actuarial losses		1
Reclassification of actuarial losses to regulatory liabilities	4
Net amount recognized in accumulated other comprehensive (income)/loss	2	2
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(20)	(12)
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	228	74
Deferred income tax liability		(2)
Actuarial gain/loss arising during the year		2
Reclassification of actuarial losses to regulatory assets		4
Net amount recognized in accumulated other comprehensive (income)/loss		4
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	170	43
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	28	28
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory liabilities, net (decrease) increase	(1)	(1)
Deferred income tax liability	(4)	(1)
Actuarial gain/loss arising during the year	2	2
Amortization of prior year actuarial losses	1	1
Prior service credit	1
Reclassification of actuarial losses to an affiliate	6
Net amount recognized in accumulated other comprehensive (income)/loss	6	2
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets, net increase (decrease)	(6)	(7)
Regulatory liabilities, net (decrease) increase	$ (2)	$ 12