Income Tax Expense - Difference Between Income Taxes Computed using the Statutory Corporate Income Tax Rates and the Recorded Income Taxes (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of average effective tax rate and applicable tax rate [abstract]
Income taxes at statutory income tax rate	₩ 1,083,029	₩ 823,124	₩ 506,804
Non-taxable income	(19,450)	(40,080)	(38,989)
Non-deductible expenses	26,724	31,285	52,648
Tax credit and tax reduction	(17,580)	(34,300)	(29,484)
Changes in unrecognized deferred taxes	(177,902)	31,857	(84,276)
Changes in tax rate	(3,983)	43,977	1,736
Income tax refund etc.	(46,860)	(110,209)	27,599
Income tax expense	₩ 843,978	₩ 745,654	₩ 436,038

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

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No definition available.

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The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to changes in the tax rate. [Refer: Accounting profit]

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The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to expenses not deductible in determining taxable profit (tax loss). [Refer: Accounting profit]

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The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to revenues that are exempt from taxation. [Refer: Accounting profit]

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The product of the accounting profit multiplied by the applicable tax rate(s). [Refer: Accounting profit; Applicable tax rate]

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Income tax paid or refund.

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- Definition

Change in unrecognized deferred tax assets.

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Tax credit and tax reduction.

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