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Leases - Summary of balance sheet information about leases for lessee (Detail) - KRW (₩) ₩ in Millions | Dec. 31, 2019 | Jan. 01, 2019 | Dec. 31, 2018 | Dec. 31, 2017
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Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets | ₩ 788,497 | ₩ 899,783 |  |
Investment property | 1,387,430 | 46,666 | ₩ 1,091,084 | ₩ 1,189,531
Lease liabilities |  |  |  |
Current | 336,530 | 336,530 |  |
Non-Current | 470,703 | 470,703 |  |
Lease liability recognized | 807,233 | 807,233 | ₩ 163,858 |
Previously stated [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets | 788,497 |  |  |
Investment property | 50,010 |  |  |
Lease liabilities |  |  |  |
Current | 355,833 |  |  |
Non-Current | 373,306 |  |  |
Lease liability recognized | 729,139 |  |  |
Property and building [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets |  | 559,813 |  |
Property and building [member] | Previously stated [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets | 540,787 |  |  |
Machinery and track facilities [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets |  | 234,507 |  |
Machinery and track facilities [member] | Previously stated [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets | 140,296 |  |  |
Other [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets |  | ₩ 105,463 |  |
Other [member] | Previously stated [member] |  |  |  |
Disclosure of balance sheet information about leases for lessee [Line Items] |  |  |  |
Right-of-use assets | ₩ 107,414 |  |  |

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- Definition The amount of current lease liabilities. [Refer: Lease liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 47 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_47_b&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of property (land or a building - or part of a building - or both) held (by the owner or by the lessee as a right-of-use asset) to earn rentals or for capital appreciation or both, rather than for: (a) use in the production or supply of goods or services or for administrative purposes; or (b) sale in the ordinary course of business. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2019-01-01 -Paragraph 76 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2019-en-r&anchor=para_76&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 40 -IssueDate 2019-01-01 -Paragraph 79 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=40&code=ifrs-tx-2019-en-r&anchor=para_79_d&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 54 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_b&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 47 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_47_b&doctype=Standard -URIDate 2019-03-27 + Details
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- References No definition available. + Details
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- Definition The amount of non-current lease liabilities. [Refer: Lease liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 47 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_47_b&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of assets that represent a lessee's right to use an underlying asset for the lease term. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph j -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_j&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition Disclosure of balance sheet information about leases for lessee + References No definition available. + Details
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