Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt)(Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 2,075	$ 2,074
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 373
Parent Company [Member] | Unsecured Debt [Member] | 2.150% Unsecured Debt Maturing November 2016 [Member]
Debt Instrument [Line Items]
Interest rate	2.15%
Current maturities of long-term debt	$ 500
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]
Interest rate	1.75%
Current maturities of long-term debt	$ 350
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member] | February 2017 Debt Maturity [Member]
Debt Instrument [Line Items]
Interest rate	3.60%
Current maturities of long-term debt	$ 77
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 252	2
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | 0.836% First Mortgage Bonds Maturing March 2017 [Member]
Debt Instrument [Line Items]
Interest rate	0.836%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	13	13
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 55	106
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member] | August 2027 Debt Maturity [Member]
Debt Instrument [Line Items]
Interest rate	1.266%
Current maturities of long-term debt	$ 50
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 547	$ 547
Duke Energy Indiana [Member] | Unsecured Debt [Member] | 6.050% 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] | 0.937% First Mortgage Bonds Maturing July 2016 [Member]
Debt Instrument [Line Items]
Interest rate	0.937%
Current maturities of long-term debt	$ 150