Schedule I - Condensed Parent Company Financial Statements (Summary Of Debt And Related Terms) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Unsecured debt	12,722		8,961
Capital leases	1,689	[1]	306
Notes Payable And Commercial Paper	1,195	[2]	604	[3]
Current maturities of long-term debt	3,110		1,894
Total long-term debt	36,351		18,679
Parent Company [Member]
Debt Instrument [Line Items]
Unsecured debt	4,929		3,773
Capital leases	127
Notes Receivable, Related Parties, Noncurrent	450		450
Notes Payable And Commercial Paper	1,195	[4]	604	[4]
Notes Payable, Related Parties, Noncurrent	105	[5]	105	[5]
Total Debt	6,356		4,482
Current maturities of long-term debt	256		0
Total long-term debt	5,355		4,328
Unsecured Debt [Member]
Debt Instrument [Line Items]
Weighted-Average Rate	5.44%		5.93%
Debt Instrument Maturity Range Start	2013		2012
Debt Instrument Maturity Range End	2039		2039
Unsecured Debt [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Weighted-Average Rate	4.10%
Debt Instrument Maturity Range Start	2013
Debt Instrument Maturity Range End	2026
CommercialPaper | Parent Company [Member]
Debt Instrument [Line Items]
Weighted Average Days To Maturity	18		17
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Weighted-Average Rate	5.19%		8.10%
Debt Instrument Maturity Range Start	2013		2012
Debt Instrument Maturity Range End	2051		2047
Capital Lease Obligations [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Weighted-Average Rate	7.80%
Debt Instrument Maturity Range End	2046
Intercompany Borrowings [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Weighted-Average Rate	0.50%
Debt Instrument Maturity Range End	2021

[1] At December 31, 2012, capital leases of Duke Energy included $158 million and $907 million of capital lease purchase accounting adjustments for Progress Energy Carolinas and Progress Energy Florida, respectively, related to power purchase agreements that are not accounted for as leases on their financial statements because of grandfathering provisions in GAAP.

[2] Includes $450 million that was classified as Long-term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted-average days to maturity was 18 days.

[3] Includes $450 million that was classified as Long-term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted-average days to maturity was 17 days.

[4] Includes $450 million at December 31, 2012 and 2011 that was classified as Long-term Debt on the Condensed Balance Sheets due to the existence of long-term credit facilities which back-stop these commercial paper balances, along with Duke Energy's ability and intent to refinance these balances on a long-term basis. The weighted-average days to maturity was 18 days and 17 days as of December 31, 2012 and 2011, respectively.

[5] This amount represents an intercompany loan with Duke Energy's affiliate, Bison Insurance Company Limited.