Debt and Credit Facilities (Summary of Debt Issuances) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended					6 Months Ended									6 Months Ended				6 Months Ended						6 Months Ended									6 Months Ended				6 Months Ended									6 Months Ended			6 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Unsecured Debt [Member] June 2013 [Member]	Jun. 30, 2013 Unsecured Debt [Member] June 2013 [Member] June 2018 [Member]		Jun. 30, 2013 Unsecured Debt [Member] January 2013 [Member] January 2073 [Member]		Jun. 30, 2013 Secured Debt [Member] April 2013 [Member] April 2026 [Member]		Mar. 31, 2013 Secured Debt [Member] April 2013 [Member] April 2026 [Member]	Jun. 30, 2013 Secured Debt [Member] February 2013 [Member] June 2037 [Member]		Jun. 30, 2013 Secured Debt [Member] February 2013 [Member] December 2030 [Member]		Jun. 30, 2013 Secured Debt [Member] Bridge Loan [Member] April 2013 [Member] April 2026 [Member]	Jun. 30, 2013 First Mortgage Bonds [Member] February 2017 [Member]	Jun. 30, 2013 First Mortgage Bonds [Member] July 2013 [Member] July 2043 [Member]		Jun. 30, 2013 First Mortgage Bonds [Member] July 2013 [Member] July 2016 [Member]		Jun. 30, 2013 First Mortgage Bonds [Member] June 2013 [Member] June 2041 [Member]		Jun. 30, 2013 First Mortgage Bonds [Member] March 2013 [Member] March 2043 [Member]		Jun. 30, 2013 Duke Energy Carolinas [Member]	Jun. 30, 2012 Duke Energy Carolinas [Member]	Jun. 30, 2013 Progress Energy [Member]	Jun. 30, 2012 Progress Energy [Member]	Jun. 30, 2013 Progress Energy [Member] Corporate Debt Securities [Member]	Jun. 30, 2013 Duke Energy Progress [Member]	Jun. 30, 2012 Duke Energy Progress [Member]	Jun. 30, 2013 Duke Energy Progress [Member] First Mortgage Bonds [Member] February 2017 [Member]	Jun. 30, 2013 Duke Energy Progress [Member] First Mortgage Bonds [Member] September 2013 [Member]	Jun. 30, 2013 Duke Energy Progress [Member] First Mortgage Bonds [Member] June 2013 [Member] June 2041 [Member]		Jun. 30, 2013 Duke Energy Progress [Member] First Mortgage Bonds [Member] March 2013 [Member] March 2043 [Member]		Jun. 30, 2013 Duke Energy Florida [Member]	Jun. 30, 2012 Duke Energy Florida [Member]	Jun. 30, 2013 Duke Energy Ohio [Member]	Jun. 30, 2012 Duke Energy Ohio [Member]	Jun. 30, 2013 Duke Energy Indiana [Member]	Jun. 30, 2012 Duke Energy Indiana [Member]	Jun. 30, 2013 Duke Energy Indiana [Member] Unsecured Debt [Member] September 2013 [Member]	Jun. 30, 2013 Duke Energy Indiana [Member] First Mortgage Bonds [Member] July 2013 [Member] July 2043 [Member]		Jun. 30, 2013 Duke Energy Indiana [Member] First Mortgage Bonds [Member] July 2013 [Member] July 2016 [Member]		Jun. 30, 2013 Parent Company [Member]	Jun. 30, 2013 Parent Company [Member] Unsecured Debt [Member] June 2013 [Member]	Jun. 30, 2013 Parent Company [Member] Unsecured Debt [Member] June 2013 [Member] June 2018 [Member]		Jun. 30, 2013 Parent Company [Member] Unsecured Debt [Member] January 2013 [Member] January 2073 [Member]
Debt Instrument [Line Items]
Unsecured debt issuances				$ 500	[1]	$ 500	[2]																																												$ 500	[1]	$ 500	[2]
Secured debt issuances								230	[3]		220	[4]	203	[4],[5]
First mortgage bonds issuances																	350	[6]	150	[6],[7]	48	[8]	500	[9]										48	[8]	500	[9]								350	[6]	150	[6],[7]
Total issuances	2,701																													548												500							1,000
Interest rate			5.65%	2.10%		5.125%				5.456%	4.74%		2.043%			5.375%	4.90%		0.619%		4.00%		4.10%						7.10%			5.375%	5.125%	4.00%		4.10%								5.00%	4.90%		0.619%			5.65%	2.10%		5.125%
Debt instrument, call date, earliest						Jan. 01, 2018															Jun. 01, 2023													Jun. 01, 2023																			Jan. 01, 2018
Payments for the redemption of long-term debt	1,538	878	250												190	48									0	751	788	455	300	50	1	48						429	4	253	4	1	2	400						250
Percentage of debt hedged by interest rate derivatives								75.00%					95.00%
Incremental debt proceeds															$ 40
Fixed credit spread																			0.35%																												0.35%

[1] Proceeds from the issuance were used to repay at maturity the $250 million 5.65% senior notes due June 15, 2013. The remaining net proceeds were used for general corporate purposes, including the repayment of outstanding commercial paper.

[2] Callable after January 2018 at par. Proceeds from the issuance were used to redeem the $300 million 7.10% Cumulative Quarterly Income Preferred Securities (QUIPS). The securities were redeemed at par plus accrued and unpaid distributions, payable upon presentation on the redemption date. The remaining net proceeds were used to repay a portion of outstanding commercial paper and for general corporate purposes. See Note 11 for additional information about the QUIPS.

[3] Represents primarily the conversion of a $190 million bridge loan issued in conjunction with the acquisition of Ibener in December 2012. Duke Energy received incremental proceeds of $40 million upon conversion of the bridge loan. The debt is floating rate and is denominated in U.S. dollars. Duke Energy has entered into a pay fixed-receive floating interest rate swap for 75 percent of the loan.

[4] Represents the conversion of construction loans related to a renewable energy project issued in December 2012 to term loans. No cash proceeds were received in conjunction with the conversion. The term loans have varying maturity dates. The maturity date presented represents the latest date for all components of the respective loans.

[5] The debt is floating rate. Duke Energy has entered into a pay fixed-receive floating interest rate swap for 95 percent of the loans.

[6] Proceeds from the issuances will be used to repay the $400 million, 5.00% unsecured debt due September 15, 2013.

[7] The debt is floating rate based on 3-month LIBOR and a fixed credit spread of 35 basis points.

[8] Callable after June 2023 at par. Proceeds from the issuance were used to redeem the $48 million 5.375% First Mortgage Bonds due February 2017, which were called for redemption on June 7, 2013.

[9] Proceeds from the issuance were used to repay notes payable to affiliated companies as well as for general corporate purposes.