Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 79	$ 75
Provisions / adjustments	9	4
Cash reductions	(6)	(12)
Ending balance	82	67
Loss contingency, range of possible loss, portion not acccrued	90
Duke Energy Carolinas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	11	12
Provisions / adjustments	(1)
Cash reductions
Ending balance	10	12
Loss contingency, range of possible loss, portion not acccrued	25
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	27	33
Provisions / adjustments	4	4
Cash reductions	(4)	(3)
Ending balance	27	34
Loss contingency, range of possible loss, portion not acccrued	9
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	8	14
Provisions / adjustments	3	1
Cash reductions	(2)	(1)
Ending balance	9	14
Loss contingency, range of possible loss, portion not acccrued	2
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	19	19
Provisions / adjustments	1	3
Cash reductions	(2)	(2)
Ending balance	18	20
Loss contingency, range of possible loss, portion not acccrued	7
Duke Energy Ohio [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	27	15
Provisions / adjustments	5	(1)
Cash reductions	(1)	(6)
Ending balance	31	8
Loss contingency, range of possible loss, portion not acccrued	51
Duke Energy Indiana [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	7	8
Provisions / adjustments		1
Cash reductions		(2)
Ending balance	7	7
Loss contingency, range of possible loss, portion not acccrued	$ 5