Commitments and Contingencies (Schedule of Environmental Loss Contingencies)(Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 97	$ 79	$ 75
Provision/adjustments	9	32	26
Cash reductions	(9)	(14)	(22)
Ending balance	97	97	79
Duke Energy Carolinas [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	11	12
Provision/adjustments	1	(1)
Cash reductions	(1)		(1)
Ending balance	10	10	11
Progress Energy [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	17	27	33
Provision/adjustments	4	1	4
Cash reductions	(4)	(11)	(10)
Ending balance	17	17	27
Duke Energy Progress [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5	8	14
Provision/adjustments		4	(1)
Cash reductions	(2)	(7)	(5)
Ending balance	3	5	8
Duke Energy Florida [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	12	19	19
Provision/adjustments	4	(3)	5
Cash reductions	(2)	(4)	(5)
Ending balance	14	12	19
Duke Energy Ohio [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	54	27	15
Provision/adjustments	1	28	20
Cash reductions	(1)	(1)	(8)
Ending balance	54	54	27
Duke Energy Indiana [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	10	7	8
Provision/adjustments	5	4	1
Cash reductions	(3)	(1)	(2)
Ending balance	12	$ 10	$ 7
Environmental Reserves [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	74
Environmental Reserves [Member] | Duke Energy Carolinas [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	22
Environmental Reserves [Member] | Duke Energy Ohio [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	42
Environmental Reserves [Member] | Duke Energy Indiana [Member]
Disclosure Environmental Matters Details [Line Items]
Environmental Exit Costs, Reasonably Possible Additional Loss	$ 7