Asset Retirement Obligations (Nuclear Operating Licenses)(Details)	12 Months Ended
	Dec. 31, 2017
Duke Energy Carolinas [Member] | Catawba Units 1 and 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2043
Duke Energy Carolinas [Member] | McGuire Unit 1 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2041
Duke Energy Carolinas [Member] | McGuire Unit 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2043
Duke Energy Carolinas [Member] | Oconee Units 1 and 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2033
Duke Energy Carolinas [Member] | Oconee Unit 3 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2034
Duke Energy Progress [Member] | Brunswick Unit 1 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2036
Duke Energy Progress [Member] | Brunswick Unit 2 [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2034
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2046
Duke Energy Progress [Member] | Robinson Nuclear Station [Member]
Asset Retirement Obligation [Line Items]
Year of expiration	2030