Severance (Rollforward) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 64
Provision/adjustments	5
Cash reductions	(41)
Balance, end of period	28
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	5
Provision/adjustments	2
Cash reductions	(5)
Balance, end of period	2
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	44
Provision/adjustments	(10)
Cash reductions	(16)
Balance, end of period	18
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	11
Cash reductions	(10)
Balance, end of period	1
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	24
Provision/adjustments	(1)
Cash reductions	(6)
Balance, end of period	17
Duke Energy Ohio [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	2
Provision/adjustments	5
Cash reductions	(1)
Balance, end of period	$ 6