Variable Interest Entities (Receivables Sold)(Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
CRC Gross Receivables Sold	$ 282	$ 302
CRC Retained Interests	97	129
CRC Net Receivables Sold	185	173
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
CRC Gross Receivables Sold	289	279
CRC Retained Interests	116	139
CRC Net Receivables Sold	$ 173	$ 140