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Consolidated subsidiaries (Details)
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Korea Hydro & Nuclear Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea South-East Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea Midland Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea Western Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea Southern Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea East-West Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Engineering & Construction Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [1] Architectural engineering for utility plant and others Architectural engineering for utility plant and others
Country of incorporation of subsidiary [1] KOREA KOREA
Proportion of ownership interest in subsidiary [1] 65.77% 65.77%
KEPCO Plant Service & Engineering    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 51.00% 51.00%
KEPCO Nuclear Fuel    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Nuclear fuel Nuclear fuel
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 96.36% 96.36%
KEPCO KDN    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Electric power information technology and others Electric power information technology and others
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Garolim Tidal Power Plant    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [2] Power generation Power generation
Country of incorporation of subsidiary [2] KOREA KOREA
Proportion of ownership interest in subsidiary [2] 0.00% 49.00%
Reason [2] Under Liquidation Process  
KEPCO International HongKong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary HONG KONG HONG KONG
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO International Philippines    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Gansu International    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary HONG KONG HONG KONG
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Philippines Holdings    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Philippines Corporation    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Ilijan Corporation    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Construction and operation of utility plant Construction and operation of utility plant
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 51.00% 51.00%
KEPCO Lebanon SARL    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary LEBANON LEBANON
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Neimenggu International    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary HONG KONG HONG KONG
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Shanxi International    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary HONG KONG HONG KONG
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOMIPO Global Pte    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary SINGAPORE SINGAPORE
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Netherlands B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary NETHERLANDS NETHERLANDS
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOREA Imouraren Uranium Investment Corp.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary FRANCE FRANCE
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSEP Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOMIPO Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOWEPO Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSPO Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Middle East Holding Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary BAHRAIN BAHRAIN
Proportion of ownership interest in subsidiary 100.00% 100.00%
Qatrana Electric Power Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Construction and operation of utility plant Construction and operation of utility plant
Country of incorporation of subsidiary JORDAN JORDAN
Proportion of ownership interest in subsidiary 80.00% 80.00%
KHNP Canada Energy    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary CANADA CANADA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Bylong Australia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea Waterbury Uranium Limited Partnership    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary CANADA CANADA
Proportion of ownership interest in subsidiary 80.00% 80.00%
Korea Electric Power Nigeria    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [3] Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary [3] NIGERIA NIGERIA
Proportion of ownership interest in subsidiary [3] 0.00% 100.00%
Reason [3] Liquidated  
KEPCO Holdings de Mexico    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary MEXICO MEXICO
Proportion of ownership interest in subsidiary 100.00% 100.00%
KST Electric Power Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Construction and operation of utility plant Construction and operation of utility plant
Country of incorporation of subsidiary MEXICO MEXICO
Proportion of ownership interest in subsidiary 56.00% 56.00%
KEPCO Energy Service Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary MEXICO MEXICO
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Netherlands S3 B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary NETHERLANDS NETHERLANDS
Proportion of ownership interest in subsidiary 100.00% 100.00%
PT. KOMIPO Pembangkitan Jawa Bali    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 51.00% 51.00%
PT. Cirebon Power Service    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [4] Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary [4] INDONESIA INDONESIA
Proportion of ownership interest in subsidiary [4] 27.50% 27.50%
KOWEPO International Corporation    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 99.99% 99.99%
KOSPO Jordan    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary JORDAN JORDAN
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP Philippines Corporation    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP America    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP Renewable    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
DG Fairhaven Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
DG Whitefield    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Springfield Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KNF Canada Energy Limited    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary CANADA CANADA
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP Barbados 1 SRL    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary BARBADOS BARBADOS
Proportion of ownership interest in subsidiary 100.00% 100.00%
California Power Holdings    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Gyeonggi Green Energy    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 62.01% 62.01%
PT. Tanggamus Electric Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 52.50% 52.50%
Gyeongju Wind Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 70.00% 70.00%
KOMIPO America    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWPRC Biomass Holdings    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSEP USA INC.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
PT. EWP Indonesia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 99.96% 99.96%
KEPCO Netherlands J3 B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary NETHERLANDS NETHERLANDS
Proportion of ownership interest in subsidiary 100.00% 100.00%
Korea Offshore Wind Power B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Global One Pioneer B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary NETHERLANDS NETHERLANDS
Proportion of ownership interest in subsidiary 100.00% 100.00%
Global Energy Pioneer B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary NETHERLANDS NETHERLANDS
Proportion of ownership interest in subsidiary 100.00% 100.00%
Mira Power Limited    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [5] Power generation Power generation
Country of incorporation of subsidiary [5] PAKISTAN PAKISTAN
Proportion of ownership interest in subsidiary [5] 76.00% 76.00%
KOSEP Material    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Recycling fly ashes Recycling fly ashes
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 86.22% 86.22%
Commerce and Industry Energy    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [6] Power generation Power generation
Country of incorporation of subsidiary [6] KOREA KOREA
Proportion of ownership interest in subsidiary [6] 85.00% 59.03%
KEPCO Singapore Holdings Pte.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [3] Holding company Holding company
Country of incorporation of subsidiary [3] SINGAPORE SINGAPORE
Proportion of ownership interest in subsidiary [3] 0.00% 100.00%
Reason [3] Liquidated  
KEPCO KPS Philippines Corp.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary PHILIPPINES PHILIPPINES
Proportion of ownership interest in subsidiary 99.99% 99.99%
KOSPO Chile SpA    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary CHILE CHILE
Proportion of ownership interest in subsidiary 100.00% 100.00%
PT. KOWEPO Sumsel Operation and Maintenance Services    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 95.00% 95.00%
HeeMang Sunlight Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Fujeij Wind Power Company    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary JORDAN JORDAN
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSPO Youngnam Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Operation of utility plant Operation of utility plant
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 50.00% 50.00%
VI Carbon Professional Private Special Asset Investment Trust 1 (formally, HI Carbon Professional Private Special Asset)    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 96.67% 96.67%
Chitose Solar Power Plant LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary JAPAN JAPAN
Proportion of ownership interest in subsidiary 80.10% 80.10%
KEPCO Energy Solution    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Energy service Energy service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Solar School Plant    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSPO Power Services Limitada    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary CHILE CHILE
Proportion of ownership interest in subsidiary 65.00% 65.00%
Energy New Industry Specialized Investment Private Investment Trust    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 99.01% 99.01%
KOEN Bylong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOMIPO Bylong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOWEPO Bylong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSPO Bylong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP Bylong    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Resources development Resources development
Country of incorporation of subsidiary AUSTRALIA AUSTRALIA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOWEPO Lao International    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary LAOS LAOS
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO US    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Alamosa    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 50.10% 50.10%
KEPCO Solar of Alamosa, LLC (formerly, Cogentrix of Alamosa, LLC)    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO-LG CNS Mangilao Holdings    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 70.00% 70.00%
Mangilao Investment    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO-LG CNS Mangilao Solar    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [7] Power generation Power generation
Country of incorporation of subsidiary [7] USA USA
Proportion of ownership interest in subsidiary [7] 100.00% 100.00%
Jeju Hanlim Offshore Wind Co    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 75.99% 75.99%
PT. Siborpa Eco Power    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Construction and operation of utility plant Construction and operation of utility plant
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 55.00% 55.00%
BSK E-New Industry Fund VII    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 81.67% 81.67%
e-New Industry LB Fund 1    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 76.11% 76.11%
Songhyun e-New Industry Fund    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 80.65% 80.65%
PT. Korea Energy Indonesia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 95.00% 95.00%
KOLAT SpA    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary CHILE CHILE
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO California, LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KEPCO Mojave Holdings, LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company Holding company
Country of incorporation of subsidiary USA USA
Proportion of ownership interest in subsidiary 100.00% 100.00%
Incheon Fuel Cell Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation Power generation
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 60.00% 60.00%
KOEN Service Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance and service Facility maintenance and service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOMIPO Service Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance and service Facility maintenance and service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOWEPO Service Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance and service Facility maintenance and service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
KOSPO Service Co., Ltd    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance and service Facility maintenance and service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
EWP Service Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance and service Facility maintenance and service
Country of incorporation of subsidiary KOREA KOREA
Proportion of ownership interest in subsidiary 100.00% 100.00%
PT. KOMIPO Energy Indonesia    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Utility plant maintenance and others Utility plant maintenance and others
Country of incorporation of subsidiary INDONESIA INDONESIA
Proportion of ownership interest in subsidiary 95.00% 95.00%
KNF Partners Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
KOSPO USA Inc.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary USA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Nambu USA LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary USA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Tamra Offshore Wind Power Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [8] Power generation  
Country of incorporation of subsidiary [8] KOREA  
Proportion of ownership interest in subsidiary [8] 63.00%  
Reason [8] Additional acquisition  
KEPCO MCS Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Electric meter reading and others  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
KEPCO FMS Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Security service and others  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Firstkeepers Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Secutec Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Security service  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
SE Green Energy Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities [8] Power generation  
Country of incorporation of subsidiary [8] KOREA  
Proportion of ownership interest in subsidiary [8] 84.80%  
Reason [8] Additional acquisition  
KEPCO Mangilao America LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary USA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Mangilao Intermediate Holdings LLC    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary USA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
KEPCO CSC Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
KOAK Power Limited    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Facility maintenance  
Country of incorporation of subsidiary PARKISTAN  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
KOMIPO Europe B.V.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary SWEDEN  
Proportion of ownership interest in subsidiary 100.00%  
Reason Newly Established  
Haenanum Energy Fund    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Holding company  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 99.64%  
Reason Newly Established  
Paju Ecoenergy Co., Ltd.    
Disclosure - Ownership of KEPCO and its material consolidated subsidiaries [Line Items]    
Key operation activities Power generation  
Country of incorporation of subsidiary KOREA  
Proportion of ownership interest in subsidiary 89.00%  
Reason Newly Established  
[1] Considering treasury stocks, the effective percentage of ownership is 66.08%.
[2] The liquidation process is in progress by the appointment of a liquidator, and the Company has been reclassified the invested amount as assets held for sale as of December 31, 2019.
[3] The liquidation process has been completed during the year ended December 31, 2019.
[4] The effective percentage of ownership is less than 50%. However, this subsidiary is included in the consolidated financial statements as the Company obtained the majority of the voting power through the shareholders' agreement.
[5] As of the reporting date, the annual reporting period of all subsidiaries is December 31, except for Mira Power Limited which is November 30.
[6] The Company guarantees a certain return on investment related to Commerce and Industry Energy Co., Ltd. for the financial investors. The financial investors have a right to sell their shares to the Company which can be exercised 84 months after the date of investment. Accordingly, the purchase price including the return on investment is classified as a liability.
[7] The Company does not hold a stake, but it is included in subsidiaries because the Company has control over KEPCO-LG CNS Mangilao Holdings LLC with nomination rights among 4 out of 6 board members.
[8] The entity was reclassified from an associate to a subsidiary due to additional acquisition of interest during the year ended December 31, 2019.