Regulatory Matters (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	$ 66,355,000,000			$ 69,490,000,000
Impairment charges	1,382,000,000		0
Regulatory assets, current	1,148,000,000			895,000,000
Regulatory assets, noncurrent	9,138,000,000			9,191,000,000
Regulatory liability, noncurrent	6,125,000,000			5,949,000,000
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	23,171,000,000			23,012,000,000
Regulatory assets, current	320,000,000			295,000,000
Regulatory assets, noncurrent	1,459,000,000			1,527,000,000
Regulatory liability, noncurrent	2,601,000,000			2,576,000,000
Duke Energy Carolinas [Member] | Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Rate increase begin date	9/25/2013
Approved return on equity percentage amount by state commission	10.20%
Approved equity capital structure, percentage	53.00%
Duke Energy Carolinas [Member] | Rate Case [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Rate increase begin date	9/18/2013
Approved return on equity percentage amount by state commission	10.20%
Approved equity capital structure, percentage	53.00%
Duke Energy Carolinas [Member] | Rate Case Step One [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	204,000,000
Approved percentage rate increase by state commission	4.50%
Duke Energy Carolinas [Member] | Rate Case Step One [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	80,000,000
Approved percentage rate increase by state commission	5.50%
Duke Energy Carolinas [Member] | Rate Case Step Two [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	30,000,000
Approved percentage rate increase by state commission	0.60%
Duke Energy Carolinas [Member] | Rate Case Step Two [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	38,000,000
Approved percentage rate increase by state commission	2.60%
Duke Energy Carolinas [Member] | William State Lee III Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Potential ownership percentage	14.00%
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	13,728,000,000			13,650,000,000
Regulatory assets, current	315,000,000			127,000,000
Regulatory assets, noncurrent	1,446,000,000			1,384,000,000
Regulatory liability, noncurrent	1,792,000,000			1,673,000,000
Duke Energy Progress [Member] | Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Rate increase begin date	6/1/2013
Approved return on equity percentage amount by state commission	10.20%
Approved equity capital structure, percentage	53.00%
Duke Energy Progress [Member] | Rate Case Step One [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	147,000,000
Approved percentage rate increase by state commission	4.50%
Duke Energy Progress [Member] | Rate Case Step Two [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	31,000,000
Approved percentage rate increase by state commission	1.00%
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	9,636,000,000			9,611,000,000
Regulatory assets, current	214,000,000			221,000,000
Regulatory assets, noncurrent	2,711,000,000			2,729,000,000
Regulatory liability, noncurrent	609,000,000			618,000,000
Duke Energy Florida [Member] | Removal Costs [Member]
Public Utilities, General Disclosures [Line Items]
Amount of reduction to carrying amount of regulatory liabilities			56,000,000
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member] | New Generation Needs [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	10.50%
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Decommissioning cost study estimate	1,180,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | Amount Subject To Cost Cap [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	1,321,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | Uprate And Dry Cask Storage Projects [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent	311,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	7.35%
Cost Cap for customers	1,466,000,000
Acceleration of cash recovery through fuel clause	130,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	121,000,000
Restructuring reserve	25,000,000
Regulatory assets, current	96,000,000
Regulatory assets, noncurrent	31,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Net unrecovered investment	248,000,000
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	4,833,000,000			8,235,000,000
Impairment charges	1,417,000,000
Regulatory assets, current	45,000,000			57,000,000
Regulatory assets, noncurrent	483,000,000			471,000,000
Regulatory liability, noncurrent	264,000,000			262,000,000
Duke Energy Ohio [Member] | Electric Rate Case [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	49,000,000
Rate increase begin date	5/1/2013
Approved percentage rate increase by state commission	2.90%
Approved return on equity percentage amount by state commission	9.84%
Duke Energy Ohio [Member] | Natural Gas Rate Case [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission	9.84%
Duke Energy Ohio [Member] | MGP Remidiation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase amount by state commission	56,000,000
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
MISO estimate of Duke Energy Ohio's MVP obligation	2,700,000,000
Recovery costs not sought	121,000,000
Restructuring reserve	95,000,000	[1]		95,000,000
Regulatory assets, noncurrent	74,000,000
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment	8,584,000,000			8,576,000,000
Regulatory assets, current	178,000,000			118,000,000
Regulatory assets, noncurrent	669,000,000			717,000,000
Regulatory liability, noncurrent	796,000,000			782,000,000
Duke Energy Indiana [Member] | Edwardsport IGCC Plant [Member] | Edwardsport Event November 20, 2007 [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC	1,985,000,000
Duke Energy Indiana [Member] | Edwardsport IGCC Plant [Member] | Edwardsport Event December 27, 2012 [Member]
Public Utilities, General Disclosures [Line Items]
Cost Cap for customers	$ 2,595,000,000

[1] As of March 31, 2014, $74 million is recorded as a Regulatory asset on Duke Energy Ohio's Condensed Consolidated Balance Sheets.