Guarantees (Narrative) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended		12 Months Ended		12 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Surety Bond [Member]	Dec. 31, 2013 Standby Letters Of Credit [Member]	Dec. 31, 2013 Performance Guarantee [Member]	Dec. 31, 2013 Performance Guarantee [Member] Less Than Wholly Owned Entity [Member]	Dec. 31, 2013 Spectra Capital [Member] Performance Guarantee [Member]	Dec. 31, 2013 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Dec. 31, 2013 Progress Energy [Member] Indemnification Agreement [Member]	Dec. 31, 2013 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]
Guarantor Obligations [Line Items]
Maximum potential amount of future payments associated with guarantees			$ 92		$ 285	$ 15	$ 205			$ 117
Guarantee obligations, unlimited exposure										Certain indemnifications related to discontinued operations have no limitations as to time or maximum potential future payments.
Guarantor obligations, term			At December 31, 2013, Duke Energy had guaranteed $92 million of outstanding surety bonds. Of this amount, $54 million, expire in 2014, the remaining expires between 2015 – 2021.		The maximum potential amount of future payments required under these guarantees as of December 31, 2013, was $285 million. Of this amount, $15 million relates to guarantees issued on behalf of less than wholly owned consolidated entities, with the remainder related to guarantees issued on behalf of third parties and unconsolidated affiliates of Duke Energy. Of the guarantees noted above, $102 million of the guarantees expire between 2015 and 2033, with the remaining performance guarantees having no contractual expiration.		At December 31, 2013, the maximum potential amount of future payments associated with these guarantees was $205 million, the majority of which expires by 2028.			At December 31, 2013, the estimated maximum exposure for these indemnifications was $117 million, the majority of which expires in 2017. Of this amount, $7 million has no contractual expiration.
Unused letters of credit				457
Liabilities Recorded for Third Party Guarantees [Abstract]
Face value of guarantees	$ 24	$ 41						$ 9	$ 25		$ 3	$ 17