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Financial Instruments by Category - Summary of Gains or Losses Arising From Financial Instruments by Category (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest income | ₩ 279,607 | ₩ 271,925 | ₩ 273,460
Interest expense | (356,345) | (293,854) | (263,389)
Total | (92,910) | (353,980) | 215,095
Other comprehensive income (loss) for the year | 7,447 | (2,194) | 165,567
Reclassified to profit or loss from other comprehensive income (loss) for the year | (37,942) | (95,421) |
Interest expense | (52,035) | (41,469) | (36,651)
Financial liabilities designated as at fair value through profit or loss [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest expense | (44) | (4,046) |
Gain on foreign currency transaction | (5) | 24 | (2)
Gain (loss) on disposal | 4,788 |  | 2,136
Gain (loss) on valuation | (7,394) | 30,031 | 42,447
Derivatives used for hedging [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Gain (loss) on transactions |  | (1,291) | (6,208)
Gain (loss) on valuation | 11,503 | (17,237) | (7,206)
Other comprehensive income (loss) for the year | 7,557 | (23,957) | (3,112)
Reclassified to profit or loss from other comprehensive income (loss) for the year | (8,764) | 15,195 | 6,722
Financial liabilities at amortized cost [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest expense | (358,486) | (275,302) | (232,197)
Gain on foreign currency transaction | (24,054) | (34,574) | (3,580)
Gain (loss) on foreign currency translation | (93,004) | (168,577) | (201,623)
Gain (loss) on valuation | 3,411 |  |
Lease liabilities [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest expense | (52,035) | (41,469) | (36,650)
Financial assets at amortized cost [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest income | 360,134 | 144,505 | 74,937
Gain on foreign currency transaction | 22,782 | 23,824 | 12,826
Gain (loss) on foreign currency translation | 5,741 | (2,151) | 2,911
Gain (loss) on disposal | (3,409) | (81) | 35
Gain (loss) on valuation | (172,966) | (132,102) | (110,286)
Financial assets at fair value through profit or loss [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest income | 13,480 | 6,008 | 3,673
Dividend income | 6,918 | 4,600 | 21,499
Gain on foreign currency transaction |  | 1,100 |
Gain (loss) on foreign currency translation | 3,396 | 13,711 | 17,794
Gain (loss) on disposal | 14,237 | 2,347 | 29,974
Gain (loss) on valuation | (31,965) | (29,282) | 64,659
Financial assets at fair value through other comprehensive income [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Interest income | 18,966 | 190,281 | 222,290
Dividend income | 52,813 | 9,522 | 1,365
Gain (loss) on disposal | (11,193) | (62,183) | (22,712)
Gain (loss) on valuation |  | (61) |
Other comprehensive income (loss) for the year | 121,805 | (158,574) | 129,780
Derivatives financial assets for hedging [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Gain (loss) on transactions | 10,192 | 27,628 |
Gain (loss) on valuation | 34,092 | 150,699 | 203,961
Other comprehensive income (loss) for the year | 7,772 | 88,048 | 144,967
Reclassified to profit or loss from other comprehensive income (loss) for the year | ₩ (29,178) | ₩ (110,616) | ₩ (143,305)

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