Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) (USD $) In Millions, unless otherwise specified						9 Months Ended				9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Other Debt Obligations [Member]	Sep. 30, 2014 Duke Energy Progress [Member]	Dec. 31, 2013 Duke Energy Progress [Member]	Sep. 30, 2014 Duke Energy Progress [Member] First Mortgage Bonds [Member] April 2015 Maturity 1 [Member]	Sep. 30, 2014 Parent Company [Member] Unsecured Debt [Member] April 2015 Maturity 1 [Member]	Sep. 30, 2014 Duke Energy Ohio [Member]	Dec. 31, 2013 Duke Energy Ohio [Member]	Sep. 30, 2014 Duke Energy Ohio [Member] First Mortgage Bonds [Member] March 2015 [Member]
Debt Instrument [Line Items]
Debt maturity date						Apr. 30, 2015	Apr. 30, 2015			Mar. 31, 2015
Interest rate						5.15%	3.35%			0.373%
Current maturities of long-term debt	$ 1,156	$ 2,104	$ 256	$ 306	$ 174	$ 300	$ 450	$ 197	$ 47	$ 150