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Operating segments (Details) - KRW (₩) ₩ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Jan. 01, 2019
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | ₩ 58,568,082 | ₩ 60,033,062 | ₩ 59,335,889 |
Intersegment revenue | 0 | 0 | 0 |
Revenue from external customers | 58,568,082 | 60,033,062 | 59,335,889 |
Depreciation and amortisation | 11,128,740 | 10,024,794 | 9,773,711 |
Interest income | 268,118 | 223,767 | 206,143 |
Interest expense | 2,046,811 | 1,868,458 | 1,789,552 |
Employee benefit expense | 725,120 | 360,575 | 391,360 |
Loss on abandonment of property, plant and equipment | 364,233 | 481,176 | 424,091 |
Increase in provisions, net | 2,301,215 | 1,056,994 | 1,690,120 |
Operating profit (loss) | (1,707,527) | (685,109) | 5,319,869 |
Finance income | 1,009,706 | 796,870 | 1,530,618 |
Finance expense | (2,782,156) | (2,470,743) | (3,127,952) |
Profit (loss) related to associates and joint ventures | 214,139 | 358,163 | (108,317) |
Profit (loss) before income tax | (3,265,838) | (2,000,819) | 3,614,218 |
Segment assets | 197,597,792 | 185,249,061 | 181,788,915 | ₩ 190,192,645
Investments in associates and joint ventures | 5,914,831 | 5,878,345 | 5,330,696 |
Acquisition of non-current assets | 14,229,785 | 12,377,457 | 12,679,845 |
Segment liabilities | 128,708,143 | 114,156,299 | 108,824,274 | ₩ 119,099,883
Operating segments |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 95,197,218 | 97,262,180 | 94,974,836 |
Intersegment revenue | 36,629,136 | 37,229,118 | 35,638,947 |
Revenue from external customers | 58,568,082 | 60,033,062 | 59,335,889 |
Depreciation and amortisation | 11,250,366 | 10,081,743 | 9,833,297 |
Interest income | 301,857 | 268,043 | 230,685 |
Interest expense | 2,081,559 | 1,912,094 | 1,818,399 |
Employee benefit expense | 737,207 | 391,055 | 421,827 |
Loss on abandonment of property, plant and equipment | 364,233 | 481,176 | 424,091 |
Increase in provisions, net | 2,553,019 | 1,049,005 | 2,076,867 |
Operating profit (loss) | (1,411,975) | (557,368) | 5,152,814 |
Profit (loss) related to associates and joint ventures | 214,138 | 358,163 | (108,317) |
Segment assets | 235,492,772 | 223,823,428 | 220,561,693 |
Investments in associates and joint ventures | 5,914,831 | 5,878,345 | 5,330,696 |
Acquisition of non-current assets | 14,311,340 | 12,440,174 | 12,656,229 |
Segment liabilities | 130,033,377 | 115,812,546 | 110,538,279 |
Operating segments | Transmission and distribution |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 58,328,372 | 59,676,952 | 59,486,766 |
Intersegment revenue | 1,336,725 | 1,393,120 | 2,044,160 |
Revenue from external customers | 56,991,647 | 58,283,832 | 57,442,606 |
Depreciation and amortisation | 3,814,428 | 3,555,158 | 3,466,410 |
Interest income | 73,478 | 77,925 | 49,987 |
Interest expense | 777,120 | 708,329 | 737,971 |
Employee benefit expense | 298,144 | 144,180 | 158,738 |
Loss on abandonment of property, plant and equipment | 350,865 | 424,774 | 384,595 |
Increase in provisions, net | 987,828 | 580,931 | 885,195 |
Operating profit (loss) | (2,568,529) | (1,814,363) | 1,902,634 |
Profit (loss) related to associates and joint ventures | 140,757 | 287,268 | (105,166) |
Segment assets | 109,809,254 | 107,486,379 | 106,540,154 |
Investments in associates and joint ventures | 3,716,931 | 3,671,897 | 3,366,309 |
Acquisition of non-current assets | 6,340,593 | 6,323,504 | 6,606,512 |
Segment liabilities | 58,350,681 | 53,404,610 | 50,757,798 |
Operating segments | Electric power generation (Nuclear) |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 8,937,026 | 8,858,717 | 9,415,752 |
Intersegment revenue | 8,908,803 | 8,833,787 | 9,359,468 |
Revenue from external customers | 28,223 | 24,930 | 56,284 |
Depreciation and amortisation | 3,227,695 | 3,088,019 | 3,267,510 |
Interest income | 37,277 | 30,422 | 21,034 |
Interest expense | 511,864 | 503,161 | 487,503 |
Employee benefit expense | 132,283 | 76,467 | 80,809 |
Loss on abandonment of property, plant and equipment | 0 | 38,886 | 0 |
Increase in provisions, net | 672,134 | 520,167 | 801,800 |
Operating profit (loss) | 782,511 | 357,401 | 1,347,794 |
Profit (loss) related to associates and joint ventures | (5,497) | 9,946 | 3,637 |
Segment assets | 59,562,190 | 55,792,704 | 55,011,096 |
Investments in associates and joint ventures | 59,081 | 43,038 | 11,843 |
Acquisition of non-current assets | 2,574,358 | 2,187,077 | 2,083,967 |
Segment liabilities | 33,909,152 | 30,484,104 | 29,252,816 |
Operating segments | Electric power generation (Non-nuclear) |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 24,254,957 | 25,204,085 | 22,795,816 |
Intersegment revenue | 23,472,153 | 24,389,816 | 21,885,251 |
Revenue from external customers | 782,804 | 814,269 | 910,565 |
Depreciation and amortisation | 3,955,333 | 3,269,023 | 2,954,375 |
Interest income | 35,626 | 29,313 | 18,860 |
Interest expense | 655,466 | 577,441 | 486,176 |
Employee benefit expense | 163,626 | 91,140 | 94,075 |
Loss on abandonment of property, plant and equipment | 13,364 | 17,516 | 39,335 |
Increase in provisions, net | 766,407 | (227,234) | 171,457 |
Operating profit (loss) | 551,287 | 482,418 | 1,523,497 |
Profit (loss) related to associates and joint ventures | 77,641 | 58,993 | (6,718) |
Segment assets | 54,758,933 | 49,296,392 | 47,938,084 |
Investments in associates and joint ventures | 2,088,581 | 2,114,203 | 1,904,224 |
Acquisition of non-current assets | 4,955,784 | 3,435,222 | 3,250,524 |
Segment liabilities | 33,117,193 | 27,558,156 | 26,337,295 |
Operating segments | Plant maintenance & engineering service |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 2,627,539 | 2,526,126 | 2,621,440 |
Intersegment revenue | 2,254,841 | 2,170,959 | 2,211,716 |
Revenue from external customers | 372,698 | 355,167 | 409,724 |
Depreciation and amortisation | 125,546 | 114,030 | 109,001 |
Interest income | 14,214 | 12,505 | 10,801 |
Interest expense | 2,861 | 4,126 | 2,967 |
Employee benefit expense | 124,745 | 77,526 | 87,344 |
Loss on abandonment of property, plant and equipment | 0 | 0 | 161 |
Increase in provisions, net | 124,242 | 174,785 | 219,382 |
Operating profit (loss) | 312,341 | 314,755 | 265,593 |
Profit (loss) related to associates and joint ventures | 1,237 | 1,956 | (70) |
Segment assets | 3,528,879 | 3,431,068 | 3,273,959 |
Investments in associates and joint ventures | 50,238 | 49,207 | 48,320 |
Acquisition of non-current assets | 95,810 | 111,393 | 145,779 |
Segment liabilities | 1,124,855 | 1,200,390 | 1,176,627 |
Operating segments | Others |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | 1,049,324 | 996,300 | 655,062 |
Intersegment revenue | 656,614 | 441,436 | 138,352 |
Revenue from external customers | 392,710 | 554,864 | 516,710 |
Depreciation and amortisation | 127,364 | 55,513 | 36,001 |
Interest income | 141,262 | 117,878 | 130,003 |
Interest expense | 134,248 | 119,037 | 103,782 |
Employee benefit expense | 18,409 | 1,742 | 861 |
Loss on abandonment of property, plant and equipment | 4 | 0 | 0 |
Increase in provisions, net | 2,408 | 356 | (967) |
Operating profit (loss) | (489,585) | 102,421 | 113,296 |
Profit (loss) related to associates and joint ventures | 0 | 0 | 0 |
Segment assets | 7,833,516 | 7,816,885 | 7,798,400 |
Investments in associates and joint ventures | 0 | 0 | 0 |
Acquisition of non-current assets | 344,795 | 382,978 | 569,447 |
Segment liabilities | 3,531,496 | 3,165,286 | 3,013,743 |
Material reconciling items |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Total segment revenue | (36,629,136) | (37,229,118) | (35,638,947) |
Intersegment revenue | (36,629,136) | (37,229,118) | (35,638,947) |
Revenue from external customers | 0 | 0 | 0 |
Depreciation and amortisation | (121,626) | (56,949) | (59,586) |
Interest income | (33,739) | (44,276) | (24,542) |
Interest expense | (34,748) | (43,636) | (28,847) |
Employee benefit expense | (12,087) | (30,480) | (30,467) |
Loss on abandonment of property, plant and equipment | 0 | 0 | 0 |
Increase in provisions, net | (251,804) | 7,989 | (386,747) |
Operating profit (loss) | (295,552) | (127,741) | 167,055 |
Profit (loss) related to associates and joint ventures | 0 | 0 | 0 |
Segment assets | (37,894,980) | (38,574,367) | (38,772,778) |
Investments in associates and joint ventures | 0 | 0 | 0 |
Acquisition of non-current assets | (81,555) | (62,717) | 23,616 |
Segment liabilities | (1,325,234) | (1,656,247) | ₩ (1,714,005) |
Elimination of intersegment amounts |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Segment assets | (39,207,636) | (41,026,970) |  |
Investments in associates and joint ventures | 0 | 0 |  |
Acquisition of non-current assets | (81,555) | (62,717) |  |
Segment liabilities | (6,654,717) | (5,055,737) |  |
Equity method adjustment |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Segment assets | 1,791,844 | 964,234 |  |
Investments in associates and joint ventures | 0 | 0 |  |
Acquisition of non-current assets | 0 | 0 |  |
Segment liabilities | 0 | 0 |  |
Deferred taxes |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Segment assets | 2,048 | 2,131 |  |
Investments in associates and joint ventures | 0 | 0 |  |
Acquisition of non-current assets | 0 | 0 |  |
Segment liabilities | 5,329,158 | (621) |  |
Others |  |  |  |
Disclosure of operating segments [Line Items] |  |  |  |
Segment assets | (481,236) | 1,486,238 |  |
Investments in associates and joint ventures | 0 | 0 |  |
Acquisition of non-current assets | 0 | 0 |  |
Segment liabilities | ₩ 325 | ₩ 3,400,111 |  |

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