Deferred Tax Assets and Liabilities - Details Of Deductible (Taxable) Temporary Differences, Tax Credit Carryforwards and Tax Credit Carryforwards Unrecognized As Deferred Tax Assets (Liabilities) (Detail) - KRW (₩) ₩ in Millions		Dec. 31, 2025	Dec. 31, 2024
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items]
Deferred tax assets (liabilities)		₩ 3,510,156	₩ 3,504,177
Investments in subsidiaries and associates [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items]
Deferred tax assets (liabilities)		(1,115,322)
Tax credit carryforwards [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items]
Deferred tax assets (liabilities)	[1]	1,081,726
Tax loss carryforwards [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items]
Deferred tax assets (liabilities)	[2]	₩ 2,021,561

[1] (*1) Unrecognized tax credit carryforwards due to the low probability of realization in the future as of December 31, 2025, will be expired from 2026.

[2] (*2) Unrecognized tax loss carryforwards due to the low probability of realization in the future as of December 31, 2025, will be expired from 2039.