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Changes in Accounting Policies - Additional Information (Detail) - KRW (₩) ₩ in Millions |  | 12 Months Ended
--- | --- | ---
Jan. 01, 2018 | Dec. 31, 2018
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |
Description of practical expedients used for incremental cost of obtaining contract |  | As a practical expedient, the Group recognizes the incremental costs of obtaining a contracts as an expense when incurred if the amortization period of the asset is one year or less.
Increase (decrease) in prepaid expenses | ₩ 1,285,443 | ₩ 1,444,822
Increase (decrease) due to application of IFRS 15 [member] |  |
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |
Increase (decrease) in contract assets | 421,131 | 398,797
Increase (decrease) in contract liabilities | ₩ 282,836 | ₩ 347,461

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