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Deferred Income Tax and Income Tax Expense - Summary of Movement in Deferred Income Tax Assets and Liabilities (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | ₩ (220,230) | ₩ 4,367 |
Statements of profit or loss | (169,961) | (229,545) | ₩ (72,124)
Other comprehensive income | 1,631 | 4,948 |
Ending | (388,560) | (220,230) | 4,367
Deferred tax liabilities investment in subsidiaries associates and joint ventures [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (240,633) | (181,564) |
Statements of profit or loss | (18,299) | (68,166) |
Other comprehensive income | 3,748 | 9,097 |
Ending | (255,184) | (240,633) | (181,564)
Deferred tax liabilities depreciation and impairment loss [Member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (88,588) | (4,175) |
Statements of profit or loss | (62,845) | (84,413) |
Ending | (151,433) | (88,588) | (4,175)
Deferred tax liabilities plan assets [Member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (538,928) | (521,257) |
Statements of profit or loss | (5,294) | (17,340) |
Other comprehensive income | 1,322 | (331) |
Ending | (542,900) | (538,928) | (521,257)
Deferred tax liabilities advanced depreciation provision [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (339,005) | (311,918) |
Statements of profit or loss | (182,934) | (27,087) |
Ending | (521,939) | (339,005) | (311,918)
Deferred tax liabilities contract assets [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (493,917) | (509,509) |
Statements of profit or loss | 69,615 | 15,592 |
Ending | (424,302) | (493,917) | (509,509)
Deferred tax liabilities financial assets at fair value through profit or loss [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (336) | (627) |
Statements of profit or loss | (73) | 291 |
Other comprehensive income | (11) |  |
Ending | (420) | (336) | (627)
Deferred tax liabilities Financial assets at fair value through other comprehensive income [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (47,521) | (30,623) |
Statements of profit or loss | (71,396) | (33,267) |
Other comprehensive income | 58,288 | 16,369 |
Ending | (60,629) | (47,521) | (30,623)
Other deferred tax liabilities [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (623,744) | (472,153) |
Statements of profit or loss | (111,135) | (150,013) |
Other comprehensive income | (3,274) | (1,578) |
Ending | (738,153) | (623,744) | (472,153)
Deferred tax liabilities [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (2,372,672) | (2,031,826) |
Statements of profit or loss | (382,361) | (364,403) |
Other comprehensive income | 60,073 | 23,557 |
Ending | (2,694,960) | (2,372,672) | (2,031,826)
Deferred tax assets depreciation and impairment loss [Member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 225,821 | 226,960 |
Statements of profit or loss | (36,989) | (1,139) |
Ending | 188,832 | 225,821 | 226,960
Deferred tax assets contract liabilities [Member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 148,454 | 140,494 |
Statements of profit or loss | (27,165) | 7,960 |
Ending | 121,289 | 148,454 | 140,494
Deferred tax assets defined benefit liabilities [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 571,336 | 598,364 |
Statements of profit or loss | (22,423) | (8,663) |
Other comprehensive income | (67,055) | (18,365) |
Ending | 481,858 | 571,336 | 598,364
Deferred tax assets provisions [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 172,871 | 167,384 |
Statements of profit or loss | (20,894) | 5,487 |
Other comprehensive income | (22) |  |
Ending | 151,955 | 172,871 | 167,384
Other deferred tax assets [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 899,543 | 758,060 |
Statements of profit or loss | 351,317 | 141,727 |
Other comprehensive income | 8,635 | (244) |
Ending | 1,259,495 | 899,543 | 758,060
Temporary differences [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | (354,647) | (140,564) |
Statements of profit or loss | (138,515) | (219,031) |
Other comprehensive income | 1,631 | 4,948 |
Ending | (491,531) | (354,647) | (140,564)
Deferred tax assets [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 2,018,025 | 1,891,262 |
Statements of profit or loss | 243,846 | 145,372 |
Other comprehensive income | (58,442) | (18,609) |
Ending | 2,203,429 | 2,018,025 | 1,891,262
Deferred tax assets tax credit carry forwards [member] |  |  |
Disclosure of temporary difference, unused tax losses and unused tax credits [Line Items] |  |  |
Beginning | 134,417 | 144,931 |
Statements of profit or loss | (31,446) | (10,514) |
Ending | ₩ 102,971 | ₩ 134,417 | ₩ 144,931

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