Income Taxes and Other (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	$ 858	$ 863	$ 774
State income tax, net of federal income tax effect	64	50	82
Tax differential on foreign earnings	(66)	(44)	(22)
Goodwill impairment charge			175
AFUDC equity income	(101)	(91)	(82)
Other items, net	(50)	(26)	(37)
Income Tax Expense or Benefit from Continuing Operations	705	752	890
Effective tax rate	28.80%	30.50%	40.30%
Duke Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	461	457	454
State income tax, net of federal income tax effect	34	46	48
AFUDC equity income	(54)	(59)	(61)
Other items, net	12	28	16
Income Tax Expense or Benefit from Continuing Operations	453	472	457
Effective tax rate	34.30%	36.10%	35.30%
Progress Energy [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	185	319	492
State income tax, net of federal income tax effect	33	39	60
AFUDC equity income	(37)	(36)	(32)
Other items, net	(9)	1	19
Income Tax Expense or Benefit from Continuing Operations	172	323	539
Effective tax rate	32.70%	35.60%	38.30%
Progress Energy Carolinas [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	134	270	333
State income tax, net of federal income tax effect	1	18	30
AFUDC equity income	(24)	(25)	(22)
Other items, net	(1)	(7)	9
Income Tax Expense or Benefit from Continuing Operations	110	256	350
Effective tax rate	28.70%	33.20%	36.80%
Progress Energy Florida [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	145	173	255
State income tax, net of federal income tax effect	14	17	23
AFUDC equity income	(13)	(11)	(10)
Other items, net	1	1	8
Income Tax Expense or Benefit from Continuing Operations	147	180	276
Effective tax rate	35.70%	36.30%	37.90%
Duke Energy Ohio [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	96	102	(108)
State income tax, net of federal income tax effect	1	(1)	14
Goodwill impairment charge			237
AFUDC equity income	(2)	(2)	(2)
Other items, net	3	(3)	(9)
Income Tax Expense or Benefit from Continuing Operations	98	96	132
Effective tax rate	36.00%	33.10%	(43.00%)
Duke Energy Indiana [Member]
Income Tax Disclosure [Line Items]
Income tax expense, computed at the statutory rate of 35%	(43)	85	155
State income tax, net of federal income tax effect	1	13	26
AFUDC equity income	(26)	(31)	(20)
Other items, net	(5)	7	(5)
Income Tax Expense or Benefit from Continuing Operations	$ (73)	$ 74	$ 156
Effective tax rate	59.50%	30.60%	35.50%