Fair Value Of Financial Assets and Liabilities (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 16	$ 86	$ 13
Revenue, regulated electric	8	17	2	25
Revenue, non-regulated electric, natural gas	(19)	(1)	(23)	(3)
Gains on available for sale securities and other	(1)	8	(2)	9
Purchases	24	29	24	31
Sales	(3)		(3)
Issuances			6
Settlements	(10)	(54)	(3)	(63)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	(5)	1	(4)	2
Ending balance	10	86	10	86
Revenue, regulated electric	1		2
Revenue, non regulated electric and other - non-regulated	(14)		(24)	3
Total	(13)		(22)	3	85
Available For Sale Auction Rate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	28	72	29
Gains on available for sale securities and other	(1)	8	(2)	9
Settlements	(1)	(39)	(1)	(39)
Ending balance	26	41	26	41
Total					71
Available For Sale Ndtf Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	70	56	69
Purchases	3	7	3	9
Sales	(3)		(3)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	1	1	2	2
Ending balance	71	64	71	64
Total					53
Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(82)	(42)	(85)
Revenue, regulated electric	8	17	2	25
Revenue, non-regulated electric, natural gas	(19)	(1)	(23)	(3)
Purchases	21	22	21	22
Issuances			6
Settlements	(9)	(15)	(2)	(24)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	(6)		(6)
Ending balance	(87)	(19)	(87)	(19)
Revenue, regulated electric	1		2
Revenue, non regulated electric and other - non-regulated	(14)		(24)	3
Total	(13)		(22)	3	(39)
Duke Energy Carolinas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	68	68	60	65
Gains on available for sale securities and other		2		2
Purchases	3	7	3	9
Sales	(3)		(3)
Issuances			0
Settlements	1	(8)	8	(8)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	1	1	2	2
Ending balance	70	70	70	70
Revenue, regulated electric	1		(4)
Total	1		(4)
Duke Energy Carolinas [Member] | Available For Sale Auction Rate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3	12	3	12
Gains on available for sale securities and other		2		2
Sales	0
Settlements		(8)	0	(8)
Ending balance	3	6	3	6
Duke Energy Carolinas [Member] | Available For Sale Ndtf Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	70	56	69	53
Purchases	3	7	3	9
Sales	(3)		(3)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	1	1	2	2
Ending balance	71	64	71	64
Duke Energy Carolinas [Member] | Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(5)		(12)
Issuances			0
Settlements	1		8
Ending balance	(4)		(4)
Revenue, regulated electric	1		(4)
Total	1		(4)
Progress Energy [Member] | Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(31)	(27)	(38)	(24)
Issuances	1		7
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	(5)	(3)	(4)	(6)
Ending balance	(35)	(30)	(35)	(30)
Revenue, regulated electric	0	0	6
Total	0	0	6
Duke Energy Progress [Member] | Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(31)	(27)	(38)	(24)
Revenue, regulated electric			0
Issuances	1		7
Settlements			0
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	(5)	(1)	(4)	(4)
Ending balance	(35)	(28)	(35)	(28)
Revenue, regulated electric	1	0	7
Total	1	0	7
Duke Energy Ohio [Member] | Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(5)	(4)	(6)	(3)
Revenue, regulated electric			0
Revenue, non-regulated electric, natural gas	(14)	1	(10)	1
Purchases	1		1
Settlements	0	2	(3)	2
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	(1)	(1)		(2)
Ending balance	(19)	(2)	(19)	(2)
Revenue, non regulated electric and other - non-regulated	(11)		(13)	1
Total	(11)		(13)	1
Duke Energy Indiana [Member] | Derivative [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4	3	10	4
Revenue, regulated electric	7	16	2	24
Purchases	20
Sales		22	20	22
Settlements	(13)	(19)	(13)	(29)
Total gains (losses) included on the Condensed Consolidated Balance Sheet as regulatory asset or liability	0	0	(1)	1
Ending balance	$ 18	$ 22	$ 18	$ 22