Severance (Rollforward) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 136
Provision/adjustments	110
Cash reductions	(167)
Balance, end of period	79
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	78
Provision/adjustments	18
Cash reductions	(83)
Balance, end of period	13
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	23
Provision/adjustments	20
Cash reductions	(29)
Balance, end of period	14
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	19
Provision/adjustments	11
Cash reductions	(24)
Balance, end of period	6
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	4
Provision/adjustments	9
Cash reductions	(5)
Balance, end of period	$ 8