Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,342	$ 2,074
Unsecured Debt [Member] | 15.530% Unsecured Debt Maturing May 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 56
Interest rate	15.53%
Secured Debt [Member] | 2.075% Secured Debt Maturing June 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 45
Interest rate	2.075%
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 420
Parent Company [Member] | Unsecured Debt [Member] | 2.150% Unsecured Debt Maturing November 2016 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 500
Interest rate	2.15%
Parent Company [Member] | Unsecured Debt [Member] | 1.009% Unsecured Debt Maturing April 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 400
Interest rate	1.009%
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 468	356
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | 1.750% First Mortgage Bonds Maturing December 2016 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 350
Interest rate	1.75%
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member] | 3.600% Tax-exempt Bonds Maturing February 2017[Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 77
Interest rate	3.60%
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 252	2
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 0.880% First Mortgage Bonds Maturing March 2017 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 250
Interest rate	0.88%
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 48	13
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	54	106
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member] | 1.280% Tax-exempt Bonds Maturing August 2027 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 50
Interest rate	1.28%
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 221	$ 547
Duke Energy Indiana [Member] | First Mortgage Bonds [Member] | 0.979% First Mortgage Bonds Maturing July 2016 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 150
Interest rate	0.979%
Duke Energy Indiana [Member] | Tax Exempt Bonds [Member] | 1.092% Tax-exempt Bonds Maturing May 2035 [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 44
Interest rate	1.092%