Income Taxes (Schedule Of Changes To Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	$ 385	$ 342	$ 664
Acquisitions	128
Gross increases-tax positions in prior periods	29	49	36
Gross decreases-tax positions in prior periods	(4)	(18)	(43)
Gross increases-current period tax positions	28	16	5
Gross decreases - current period tax positions	(9)
Settlements	(13)	4	(320)
Statute	(4)
Total changes	155	43	(322)
Unrecognized Tax Benefits - December 31	540	385	342
Duke Energy Carolinas [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	260	217	517
Gross increases-tax positions in prior periods	12	42	14
Gross decreases-tax positions in prior periods		(8)	(7)
Gross increases-current period tax positions	15	9	3
Gross decreases - current period tax positions	(5)
Settlements	(11)		(310)
Total changes	11	43	(300)
Unrecognized Tax Benefits - December 31	271	260	217
Progress Energy [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	173	176	160
Gross increases-tax positions in prior periods	23	88	10
Gross decreases-tax positions in prior periods	(72)	(24)	(4)
Gross increases-current period tax positions	8	9	14
Gross decreases - current period tax positions	(1)	(8)	(4)
Settlements		(68)
Total changes	(42)	(3)	16
Unrecognized Tax Benefits - December 31	131	173	176
Progress Energy Carolinas [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	73	74	59
Gross increases-tax positions in prior periods	10	19	8
Gross decreases-tax positions in prior periods	(19)	(14)	(2)
Gross increases-current period tax positions	4	8	10
Gross decreases - current period tax positions	(1)	(4)	(1)
Settlements		(10)
Total changes	(6)	(1)	15
Unrecognized Tax Benefits - December 31	67	73	74
Progress Energy Florida [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	80	99	98
Gross increases-tax positions in prior periods	12	66	2
Gross decreases-tax positions in prior periods	(52)	(21)	(1)
Gross increases-current period tax positions	4	1	3
Gross decreases - current period tax positions		(4)	(3)
Settlements		(61)
Total changes	(36)	(19)	1
Unrecognized Tax Benefits - December 31	44	80	99
Duke Energy Ohio [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	32	29	32
Gross increases-tax positions in prior periods	2	4	15
Gross decreases-tax positions in prior periods		(5)	(21)
Gross increases-current period tax positions	4	4	1
Gross decreases - current period tax positions	(2)
Settlements			2
Total changes	4	3	(3)
Unrecognized Tax Benefits - December 31	36	32	29
Duke Energy Indiana [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits - January 1	24	21	28
Gross increases-tax positions in prior periods	6	3	7
Gross decreases-tax positions in prior periods		(3)	(13)
Gross increases-current period tax positions	4	3	1
Gross decreases - current period tax positions	(2)
Settlements			(2)
Total changes	8	3	(7)
Unrecognized Tax Benefits - December 31	$ 32	$ 24	$ 21