Income Taxes (Other Disclosures) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	$ 540
Gross decreases-tax positions in prior periods	(230)
Settlements	(66)
Total changes	(296)
Unrecognized Tax Benefits - September 30	244	[1]
Duke Energy Carolinas [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	271
Gross decreases-tax positions in prior periods	(96)
Settlements	(4)
Total changes	(100)
Unrecognized Tax Benefits - September 30	171	[1]
Progress Energy [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	131
Gross decreases-tax positions in prior periods	(85)
Total changes	(85)
Unrecognized Tax Benefits - September 30	46	[1]
Duke Energy Progress [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	67
Gross decreases-tax positions in prior periods	(45)
Total changes	(45)
Unrecognized Tax Benefits - September 30	22	[1]
Duke Energy Florida [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	44
Gross decreases-tax positions in prior periods	(37)
Total changes	(37)
Unrecognized Tax Benefits - September 30	7	[1]
Duke Energy Ohio [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	36
Gross decreases-tax positions in prior periods	(36)
Total changes	(36)
Unrecognized Tax Benefits - September 30	0	[1]
Duke Energy Indiana [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - January 1	32
Gross decreases-tax positions in prior periods	(31)
Total changes	(31)
Unrecognized Tax Benefits - September 30	$ 1	[1]

[1] The Duke Energy Registrants do not anticipate a significant increase or decrease in unrecognized tax benefits in the next twelve months.