Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,800	$ 2,807
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	300
Parent Company [Member] | Unsecured Debt [Member] | 3.350% Unsecured Debt Maturing April 2015 [Member]
Debt Instrument [Line Items]
Interest rate	3.35%
Current maturities of long-term debt	450
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	702	945
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 5.150% First Mortgage Bonds Maturing April 2015 [Member]
Debt Instrument [Line Items]
Interest rate	5.15%
Current maturities of long-term debt	300
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 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
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	562	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