Post-Employment Benefits - Details of Expenses Related to Defined Benefit Plans Recognized in Profit or Loss and Line Items Included in Consolidated Statements of Comprehensive Income (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of net defined benefit liability (asset) [abstract]
Defined benefit plans includes capitalized amounts	₩ 10,885	₩ 9,885	₩ 15,085
Defined benefit plans excludes capitalized amounts	₩ 10,885	₩ 9,885	₩ 15,085