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Financial Instruments - Changes in Gain or Loss Due to a Hypothetically Strengthening or Weakening in Foreign Currencies (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
10% increase [member] | USD [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ (609,961) |  | ₩ (548,525)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |
10% increase [member] | EUR [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ 16,853 |  | 13,971
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |
10% increase [member] | JPY [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ 13,283 |  | 9,049
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |
10% decrease [member] | USD [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ 609,961 |  | 548,525
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |
10% decrease [member] | EUR [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ (16,853) |  | (13,971)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |
10% decrease [member] | JPY [member] |  |  |
Disclosure of detailed information about hedging instruments [line items] |  |  |
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency | ₩ (13,283) |  | ₩ (9,049)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency | 10.00% | 10.00% |

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- Definition Increase decrease in profit (loss) on basis of strengthening of major currencies against functional currency. + References No definition available. + Details
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