Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 13	$ 85	$ 146
Total pretax gains (losses) included in earnings	(42)	8	(14)
Total pretax gains (losses) included in comprehensive income		13	12
Amounts acquired in Progress Energy merger		(30)
Purchases	30	36	16
Sales	(6)	(2)	(3)
Issuances	11	(15)
Settlements	16	(87)	(32)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	3	5	(40)
Transfers in and/or out of level 3	86
Ending balance	111	13	85
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(85)	(39)	(19)
Amounts acquired in Progress Energy merger		(30)
Total pretax gains (losses) included in earnings	(42)	8	(14)
Purchases	21	22	8
Issuances	11	(15)
Settlements	25	(32)	(16)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	(3)	1	2
Transfers out of level 3	86
Ending balance	13	(85)	(39)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	10
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	98	124	165
Total pretax gains (losses) included in comprehensive income		13	12
Purchases	9	14	8
Sales	(6)	(2)	(3)
Settlements	(9)	(55)	(16)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	6	4	(42)
Ending balance	98	98	124
Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	10
Duke Energy Carolinas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	60	65	59
Total pretax gains (losses) included in comprehensive income		2
Purchases	9	14	8
Sales	(6)	(2)	(3)
Issuances		(14)
Settlements	10	(9)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	6	4	1
Ending balance	79	60	65
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(12)
Issuances		(14)
Settlements	10	2
Ending balance	(2)	(12)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(4)
Duke Energy Carolinas [Member] | Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	72	65	59
Total pretax gains (losses) included in comprehensive income		2
Purchases	9	14	8
Sales	(6)	(2)	(3)
Settlements		(11)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	6	4	1
Ending balance	81	72	65
Duke Energy Carolinas [Member] | Derivative [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(4)
Progress Energy [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(38)	(24)	(36)
Total pretax gains (losses) included in earnings		1
Issuances	10	(16)
Settlements		4
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	(6)	(3)	(21)
Transfers out of level 3	34		33
Ending balance		(38)	(24)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	11
Duke Energy Progress [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(38)	(24)	(36)
Total pretax gains (losses) included in earnings		1
Issuances	10	(16)
Settlements		4
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	(6)	(3)	(20)
Transfers out of level 3	34		32
Ending balance		(38)	(24)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	11
Duke Energy Ohio [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(6)	(3)	13
Total pretax gains (losses) included in earnings	(42)	(3)	(4)
Purchases	1
Settlements		1	(14)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability		(1)	2
Transfers out of level 3	43
Ending balance	(4)	(6)	(3)
Duke Energy Indiana [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	10	4	4
Total pretax gains (losses) included in earnings	8	36	14
Purchases	20		8
Sales		22
Settlements	(30)	(52)	(21)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	4		(1)
Ending balance	$ 12	$ 10	$ 4