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Accumulated Other Comprehensive Income and Other Components of Equity - Summary of Treasury Stock (Detail) - KRW (₩) ₩ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Miscellaneous equity [abstract] |  |
Number of shares (in shares) | 15,967,040 | 16,014,753
Amounts (In millions of Korean won) | ₩ 830,874 | ₩ 853,108

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