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	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 111	$ 13
Total pretax gains (losses) included in earnings	18	(10)
Total pretax gains (losses) included in comprehensive income		(1)
Purchases	1
Sales	(1)
Issuances		6
Settlements	(39)	7
Transfers in and/or out of level 3	(5)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability		1
Ending balance	85	16
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	13	(85)
Total pretax gains (losses) included in earnings	18	(10)
Issuances		6
Settlements	(39)	7
Transfers out of level 3	(5)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	(1)
Ending balance	(14)	(82)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(7)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	98	98
Total pretax gains (losses) included in comprehensive income		(1)
Purchases	1
Sales	(1)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	1	1
Ending balance	99	98
Duke Energy Carolinas [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	79	60
Purchases	1
Sales	(1)
Settlements	(2)	7
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	1	1
Ending balance	78	68
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(2)	(12)
Settlements	(2)	7
Ending balance	(4)	(5)
Duke Energy Carolinas [Member] | Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	81	72
Purchases	1
Sales	(1)
Total gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	1	1
Ending balance	82	73
Progress Energy [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	(38)
Total pretax gains (losses) included in earnings	(3)
Issuances		6
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability		1
Ending balance	(3)	(31)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(3)
Duke Energy Progress [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	0	(38)
Total pretax gains (losses) included in earnings	(3)
Issuances		6
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability		1
Ending balance	(3)	(31)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(3)
Duke Energy Ohio [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	(4)	(6)
Total pretax gains (losses) included in earnings	(6)	4
Settlements	(4)	(3)
Transfers out of level 3	(5)
Ending balance	(19)	(5)
Pretax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at end of period	(7)
Duke Energy Indiana [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	12	10
Total pretax gains (losses) included in earnings	27	(5)
Settlements	(31)
Total Gains (losses) included on the Consolidated Balance Sheet as regulatory asset or liability	(1)	(1)
Ending balance	$ 7	$ 4