Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Debt issuances	$ 2,700	$ 2,922
November 2015 3.750% Senior Unsecured Notes Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 400
Interest rate	3.75%
Repayments of Debt	$ 300
November 2015 4.800% Senior Unsecured Notes Maturing December 2045 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	$ 600
Interest rate	4.80%
Repayments of Debt	$ 300
March 2015 3.750% First Mortgage Bonds Maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.75%
Repayments of Debt	$ 500
August 2015 3.250% First Mortgage bonds Maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 500
Interest rate	3.25%
Repayments of Debt	$ 400
August 2015 4.200% First Mortgage Bonds Maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	$ 700
Interest rate	4.20%
Repayments of Debt	$ 400
April 2014 3.75% Senior Unsecured Notes Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 600
Interest rate		3.75%
Repayments of Debt		$ 402
April 2014 0.613% Senior Unsecured Floating Notes Maturing April 2017 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400
Interest rate		0.613%
Fixed credit spread		0.38%
Repayments of Debt		$ 402
June 2014 11.970% Senior Unsecured Floating Notes Maturing May 2019 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 108
Interest rate		11.97%
Repayments of Debt		$ 196
June 2014 13.680% Senior Unsecured Floating Notes Maturing May 2021 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 110
Interest rate		13.68%
Repayments of Debt		$ 196
March 2014 0.863% Secured Credit Facility Maturing March 2017 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 225
Interest rate		0.863%
July 2014 5.340% Secured Debt Maturing July 2036 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 129
Interest rate		5.34%
March 2014 4.375% First Mortgage Bonds Maturing March 2044 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400
Interest rate		4.375%
March 2014 0.435% First Mortgage Bonds Maturing March 2017[Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 250
Interest rate		0.435%
Fixed credit spread		0.20%
November 2014 4.150% Fixed First Mortgage Bonds Maturing December 2044 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Interest rate		4.15%
Repayments of Debt		$ 450
November 2014 0.432% Floating First Mortgage Bonds Maturing November 2017 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 200
Interest rate		0.432%
Fixed credit spread		0.20%
Repayments of Debt		$ 450
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances	1,000	1,000
Parent Company [Member] | November 2015 3.750% Senior Unsecured Notes Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	400
Repayments of Debt	300
Parent Company [Member] | November 2015 4.800% Senior Unsecured Notes Maturing December 2045 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances	600
Repayments of Debt	300
Parent Company [Member] | April 2014 3.75% Senior Unsecured Notes Maturing April 2024 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		600
Repayments of Debt		402
Parent Company [Member] | April 2014 0.613% Senior Unsecured Floating Notes Maturing April 2017 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400
Fixed credit spread		0.38%
Repayments of Debt		$ 402
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances	500
Duke Energy Carolinas [Member] | March 2015 3.750% First Mortgage Bonds Maturing June 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	500
Repayments of Debt	500
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances	1,200	1,350
Duke Energy Progress [Member] | August 2015 3.250% First Mortgage bonds Maturing August 2025 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	500
Repayments of Debt	400
Duke Energy Progress [Member] | August 2015 4.200% First Mortgage Bonds Maturing August 2045 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances	700
Repayments of Debt	$ 400
Duke Energy Progress [Member] | March 2014 4.375% First Mortgage Bonds Maturing March 2044 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		400
Duke Energy Progress [Member] | March 2014 0.435% First Mortgage Bonds Maturing March 2017[Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 250
Fixed credit spread		0.20%
Duke Energy Progress [Member] | November 2014 4.150% Fixed First Mortgage Bonds Maturing December 2044 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500
Repayments of Debt		450
Duke Energy Progress [Member] | November 2014 0.432% Floating First Mortgage Bonds Maturing November 2017 [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Debt issuances		$ 200
Fixed credit spread		0.20%
Repayments of Debt		$ 450
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances		225
Duke Energy Florida [Member] | March 2014 0.863% Secured Credit Facility Maturing March 2017 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt issuances		$ 225