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Financial Risk Management - Summary of Maximum Exposure to Credit Risk (Detail) - KRW (₩) ₩ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | ₩ 10,508,462 | ₩ 10,220,555
Cash and cash equivalents (except for cash on hand) [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 2,284,885 | 1,926,620
Financial assets at amortized costs [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 5,425,996 | 6,793,397
Financial assets at fair value through other comprehensive income [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 1,097,348 |
Contract assets [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 398,797 |
Derivatives financial assets for hedging [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 29,843 | 7,389
Financial assets at fair value through profit or loss [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 714,653 | 5,813
Other financial assets at fair value through other comprehensive income [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 6,909 |
Other financial assets at amortized costs [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | 484,271 |
Available-for-sale [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk |  | 9,899
Held-to-maturity financial assets [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk |  | 151
Financial instruments and others [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk |  | 1,333,317
Financial guarantee contracts [member] |  |
Disclosure of detailed information about financial instruments [line items] |  |
Maximum exposure to credit risk | ₩ 65,760 | ₩ 143,969

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- Definition The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2018-01-01 -Paragraph 35K -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_35K_a&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2021-01-01 -Name IFRS -Number 7 -IssueDate 2018-01-01 -Paragraph 36 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_36_a&doctype=Standard&book=b -URIDate 2018-03-16 + Details
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