Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,536	$ 2,807
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	311
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 506	507
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 5.300% First Mortgage Bonds Maturing October 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.30%
Current maturities of long-term debt	$ 500
Progress Energy Parent [Member] | Unsecured Debt [Member] | 5.625% Unsecured Debt Maturing January 2016 [Member]
Debt Instrument [Line Items]
Interest rate	5.625%
Current maturities of long-term debt	$ 300
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 402	945
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 5.250% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.25%
Current maturities of long-term debt	$ 400
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 563	562
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 0.650% First Mortgage Bonds Maturing November 2015 [Member]
Debt Instrument [Line Items]
Interest rate	0.65%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | 5.100% First Mortgage Bonds Maturing December 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.10%
Current maturities of long-term debt	$ 300
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	56	157
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 480	$ 5
Duke Energy Indiana [Member] | Unsecured Debt [Member] | 6.05% Unsecured Debt Maturing June 2016 [Member]
Debt Instrument [Line Items]
Interest rate	6.05%
Current maturities of long-term debt	$ 325
Duke Energy Indiana [Member] | First Mortgage Bonds [Member] | 0.636% First Mortgage Bonds Maturing July 2016 [Member]
Debt Instrument [Line Items]
Interest rate	0.636%
Current maturities of long-term debt	$ 150