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Financial Risk Management - Summary of Gearing Ratios (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended |  |  |  |
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Dec. 31, 2018 | Dec. 31, 2017 | Jan. 01, 2018 | Jan. 01, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure of detailed information about financial instruments [abstract] |  |  |  |  |  |
Total borrowings | ₩ 6,648,293 | ₩ 6,860,539 |  |  |  |
Less: cash and cash equivalents | (2,703,422) | (1,928,182) |  | ₩ (2,900,311) | ₩ (2,900,311) | ₩ (2,559,464)
Net debt | 3,944,871 | 4,932,357 |  |  |  |
Total equity | 14,658,490 | 13,183,354 | ₩ 14,190,193 | ₩ 12,916,942 | ₩ 12,916,942 | ₩ 12,253,627
Total capital | ₩ 18,603,361 | ₩ 18,115,711 |  |  |  |
Gearing ratio | 21.00% | 27.00% |  |  |  |

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- Definition The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2018-01-01 -Paragraph 45 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_45&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2018-01-01 -Paragraph B13 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_B13_a&doctype=Appendix&seq=2 -URIDate 2018-03-16 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 54 -Subparagraph i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_54_i&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The amount of residual interest in the assets of the entity after deducting all its liabilities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2018-01-01 -Paragraph 24 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=1&date=2018-03-01&anchor=para_24_a&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2018-01-01 -Paragraph 32 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=1&date=2018-03-01&anchor=para_32_a_i&doctype=Standard -URIDate 2018-03-16 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2018-01-01 -Paragraph 93 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=13&date=2018-03-01&anchor=para_93_a&doctype=Standard -URIDate 2018-03-16 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2018-01-01 -Paragraph 93 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=13&date=2018-03-01&anchor=para_93_b&doctype=Standard -URIDate 2018-03-16 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2018-01-01 -Paragraph 93 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=13&date=2018-03-01&anchor=para_93_e&doctype=Standard -URIDate 2018-03-16 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard -URIDate 2018-03-16 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 78 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_78_e&doctype=Standard -URIDate 2018-03-16 + Details
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