Regulatory Matters (Narrative) (Details)		1 Months Ended	3 Months Ended				12 Months Ended
	Dec. 30, 2014 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Dec. 31, 2015 USD ($) MW	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Public Utilities, General Disclosures [Line Items]
Other Liabilities		$ 1,706,000,000					$ 1,706,000,000	$ 1,675,000,000
Accounts Payable, Current		2,400,000,000					2,400,000,000	2,271,000,000
Decommissioning cost study estimate		8,130,000,000					8,130,000,000
Restructuring Reserve		136,000,000					136,000,000	28,000,000
Regulatory assets, current		$ 877,000,000					$ 877,000,000	1,115,000,000
Net Asset Percentage Limit		25.00%					25.00%
Impairment charges							$ 120,000,000	81,000,000	$ 399,000,000
Other Nonoperating Income (Expense)							307,000,000	351,000,000	262,000,000
Net property, plant and equipment		$ 75,709,000,000					75,709,000,000	70,046,000,000
Regulated Revenue							21,379,000,000	21,550,000,000	20,329,000,000
Regulatory assets, noncurrent		11,373,000,000					11,373,000,000	11,042,000,000
Regulatory liabilities, noncurrent		6,255,000,000					6,255,000,000	6,193,000,000
Regulatory assets		12,250,000,000					12,250,000,000	12,157,000,000
Capital expenditures							6,766,000,000	5,384,000,000	5,526,000,000
Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		509,000,000					509,000,000	1,659,000,000
Nuclear asset securitizable balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		1,237,000,000					1,237,000,000
Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		245,000,000					245,000,000	296,000,000
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment		$ 352,000,000					$ 352,000,000
Capacity (in MW) | MW							1,821
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		40.00%					40.00%
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		7.50%					7.50%
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Other Liabilities		$ 621,000,000					$ 621,000,000	642,000,000
Accounts Payable, Current		753,000,000					753,000,000	709,000,000
Restructuring Reserve		78,000,000					78,000,000	2,000,000
Regulatory assets, current		305,000,000					305,000,000	399,000,000
Impairment charges							1,000,000	3,000,000
Other Nonoperating Income (Expense)							160,000,000	172,000,000	120,000,000
Net property, plant and equipment		25,877,000,000					25,877,000,000	24,672,000,000
Regulatory assets, noncurrent		2,766,000,000					2,766,000,000	2,465,000,000
Regulatory liabilities, noncurrent		2,802,000,000					2,802,000,000	2,710,000,000
Regulatory assets		3,071,000,000					3,071,000,000	2,864,000,000
Capital expenditures							1,933,000,000	1,879,000,000	1,695,000,000
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		49,000,000					49,000,000	58,000,000
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		107,000,000					$ 107,000,000	141,000,000
Duke Energy Carolinas [Member] | Minimum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period							5 years
Duke Energy Carolinas [Member] | Maximum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period							10 years
Duke Energy Carolinas [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							10.20%
Duke Energy Carolinas [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage							8.49%
Duke Energy Carolinas [Member] | William State Lee III Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment		471,000,000					$ 471,000,000
Duke Energy Carolinas [Member] | NCEMC [Member] | William States Lee Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		$ 600,000,000					$ 600,000,000
Joint owner ownership percentage		13.00%					13.00%
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Other Liabilities		$ 45,000,000					$ 45,000,000	89,000,000
Accounts Payable, Current		399,000,000					399,000,000	481,000,000
Restructuring Reserve		19,000,000					19,000,000	1,000,000
Regulatory assets, current		264,000,000					264,000,000	287,000,000
Payments to Acquire Businesses, Gross							1,249,000,000
Impairment charges							5,000,000	(18,000,000)	22,000,000
Other Nonoperating Income (Expense)							71,000,000	51,000,000	57,000,000
Net property, plant and equipment		17,720,000,000					17,720,000,000	15,186,000,000
Regulatory assets, noncurrent		2,710,000,000					2,710,000,000	2,675,000,000
Regulatory liabilities, noncurrent		1,878,000,000					1,878,000,000	1,832,000,000
Regulatory assets		2,974,000,000					2,974,000,000	2,962,000,000
Capital expenditures							$ 1,669,000,000	1,241,000,000	1,567,000,000
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period							10 years
Regulatory assets		179,000,000					$ 179,000,000	152,000,000
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		62,000,000					$ 62,000,000	43,000,000
Duke Energy Progress [Member] | Maximum [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period							10 years
Duke Energy Progress [Member] | FERC Mitigation [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges					$ (18,000,000)
Duke Energy Progress [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							10.80%
Duke Energy Progress [Member] | FERC Complaint [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage							8.49%
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		1,100,000,000					$ 1,100,000,000
Duke Energy Progress [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment		548,000,000					$ 548,000,000
Capacity (in MW) | MW							376
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges						$ 22,000,000
Regulatory assets, noncurrent		48,000,000					$ 48,000,000
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Other Liabilities		146,000,000					146,000,000	158,000,000
Accounts Payable, Current		322,000,000					322,000,000	365,000,000
Restructuring Reserve		4,000,000					4,000,000	17,000,000
Regulatory assets, current		98,000,000					98,000,000	203,000,000
Payments to Acquire Businesses, Gross							166,000,000
Impairment charges							7,000,000	2,000,000	358,000,000
Other Nonoperating Income (Expense)							24,000,000	20,000,000	30,000,000
Net property, plant and equipment		10,623,000,000					10,623,000,000	9,955,000,000
Regulatory assets, noncurrent		2,725,000,000					2,725,000,000	2,733,000,000
Regulatory liabilities, noncurrent		509,000,000					509,000,000	547,000,000
Regulatory assets		2,823,000,000					2,823,000,000	2,936,000,000
Capital expenditures							1,029,000,000	699,000,000	915,000,000
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		230,000,000					230,000,000	1,393,000,000
Duke Energy Florida [Member] | Nuclear asset securitizable balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		1,237,000,000					1,237,000,000
Duke Energy Florida [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		76,000,000					76,000,000	112,000,000
Duke Energy Florida [Member] | FPSC [Member] | Removal Costs [Member]
Public Utilities, General Disclosures [Line Items]
Amount of reduction to carrying amount of regulatory liabilities									114,000,000
Duke Energy Florida [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission							$ (14,100,000)
Approved return on equity percentage amount by state commission							10.80%
Public Utilities, Requested Return on Equity, Percentage							10.00%
Customer Refundable Fees, Refund Payments		14,100,000
Duke Energy Florida [Member] | FERC Complaint 3 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							8.69%
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							10.50%
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							9.50%
Duke Energy Florida [Member] | 2013 FPSC Settlement Agreement [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							11.50%
Duke Energy Florida [Member] | 2012 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission							$ 150,000,000
Total Customer Refunds To Be Paid							388,000,000
Customer Refund Liability, Current		70,000,000					70,000,000
Duke Energy Florida [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment		131,000,000					$ 131,000,000
Capacity (in MW) | MW							873
Duke Energy Florida [Member] | Crystal River Unit 3 [Member]
Public Utilities, General Disclosures [Line Items]
Decommissioning cost study estimate		1,180,000,000					$ 1,180,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | ISFSI Projects [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							7.35%
Regulatory assets, noncurrent		60,000,000					$ 60,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Acceleration of cash recovery through fuel clause							47,000,000
Impairment charges						295,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member] | Original Uprate Project [Member] [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent		169,000,000					169,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges			$ 15,000,000
Amount of Regulatory Costs Not yet Approved		1,298,000,000					1,298,000,000
Regulatory assets, noncurrent		1,283,000,000					$ 1,283,000,000
Duke Energy Florida [Member] | Crystal River Unit 3 [Member] | 2013 FPSC Settlement Agreement [Member] | FPSC [Member] | Nuclear asset securitizable balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period							20 years
Regulatory assets, noncurrent		1,283,000,000					$ 1,283,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Restructuring Reserve		25,000,000					25,000,000
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission							0
Duke Energy Florida [Member] | Levy Nuclear Station [Member] | 2013 FPSC Settlement Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Impairment charges						$ 65,000,000
Net unrecovered investment		183,000,000					183,000,000
Net property, plant and equipment		105,000,000					105,000,000
Regulatory assets, noncurrent		78,000,000					78,000,000
Duke Energy Florida [Member] | Citrus County Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		1,500,000,000					1,500,000,000
Duke Energy Florida [Member] | Suwannee Station [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC		197,000,000					197,000,000
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Other Liabilities		165,000,000					165,000,000	166,000,000
Accounts Payable, Current		207,000,000					207,000,000	209,000,000
Regulatory assets, current		$ 36,000,000					$ 36,000,000	49,000,000
Limit of Total Capital		30.00%					30.00%
Impairment charges								94,000,000	5,000,000
Other Nonoperating Income (Expense)							$ 6,000,000	10,000,000	2,000,000
Net property, plant and equipment		$ 5,243,000,000					5,243,000,000	4,937,000,000
Regulated Revenue							1,331,000,000	1,316,000,000	1,258,000,000
Regulatory assets, noncurrent		497,000,000					497,000,000	512,000,000
Regulatory liabilities, noncurrent		245,000,000					245,000,000	241,000,000
Regulatory assets		533,000,000					533,000,000	561,000,000
Capital expenditures							$ 399,000,000	322,000,000	434,000,000
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 Remediation [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission							$ 56,000,000
Duke Energy Ohio [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							12.38%
Duke Energy Ohio [Member] | FERC Complaint 1 [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							11.38%
Percentage Recovered Through Future Rate Case							30.00%
Duke Energy Ohio [Member] | Accelerated Natural Gas Service Line Replacement Rider | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital and operations and maintenance cost							$ 320,000,000
Duke Energy Ohio [Member] | Energy Efficiency and Peak Demand Reduction Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulated Revenue		20,000,000		$ (23,000,000)
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Restructuring Reserve		$ 92,000,000					$ 92,000,000	94,000,000
Approved MVP Proposals		17					17
MISO estimate of Duke Energy Ohio's MVP obligation							$ 2,700,000,000
Regulatory assets		$ 72,000,000					$ 72,000,000
Duke Energy Ohio [Member] | Dayton Power and Light [Member] | East Bend Station [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage	31.00%
Capital expenditures	$ 12,400,000
Duke Energy Kentucky [Member]
Public Utilities, General Disclosures [Line Items]
Required Equity Capital Structure Percent		35.00%					35.00%
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Other Liabilities		$ 65,000,000					$ 65,000,000	90,000,000
Accounts Payable, Current		189,000,000					189,000,000	179,000,000
Regulatory assets, current		102,000,000					102,000,000	93,000,000
Impairment charges							88,000,000
Other Nonoperating Income (Expense)							11,000,000	22,000,000	18,000,000
Net property, plant and equipment		9,523,000,000					9,523,000,000	8,815,000,000
Regulatory assets, noncurrent		716,000,000					716,000,000	685,000,000
Regulatory liabilities, noncurrent		754,000,000					754,000,000	796,000,000
Regulatory assets		818,000,000					818,000,000	778,000,000
Capital expenditures							690,000,000	625,000,000	$ 545,000,000
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets		51,000,000					$ 51,000,000	$ 56,000,000
Duke Energy Indiana [Member] | FERC Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							12.38%
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission							0.50%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage							8.67%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage							10.32%
Duke Energy Indiana [Member] | Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		1,900,000,000					$ 1,900,000,000
Duke Energy Indiana [Member] | Revised Grid Infrastructure Improvement Plan [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost		1,800,000,000					1,800,000,000
Duke Energy Indiana [Member] | Edwardsport IGCC Plant [Member] | IGCC Rider Proceeding [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Amount of Impairment to Carrying Amount of Regulatory Assets		80,300,000					80,300,000
Other Liabilities		7,200,000					7,200,000
Legal Fees							5,500,000
Accounts Payable, Current		5,500,000					$ 5,500,000
Regulatory Noncurrent Asset, Amortization Period							8 years
Impairment charges							$ 87,500,000
Other Nonoperating Income (Expense)							5,500,000
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount							(87,500,000)
Regulatory assets		128,000,000					128,000,000
Duke Energy Indiana [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment		$ 221,000,000					$ 221,000,000
Capacity (in MW) | MW							948
Dominion Resources [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		45.00%					45.00%
Piedmont Natural Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		10.00%					10.00%
Spectra Energy [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		59.50%					59.50%
NextEra [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage		33.00%					33.00%