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Accumulated Other Comprehensive Income and Other Components of Equity - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Beginning | ₩ 30,985 | ₩ (1,432)
Changes in accounting policy | 17,741 |
Increase /decrease | 45,711 | (54,062)
Reclassified to gain or loss | (44,279) | 86,479
Ending | 50,158 | 30,985
Changes in investments in associates and joint ventures [member] |  |
Beginning | (735) | (10,883)
Increase /decrease | (136) | 10,148
Ending | (871) | (735)
Loss on derivatives valuation [member] |  |
Beginning | (3,463) | (34,309)
Increase /decrease | 17,268 | (111,083)
Reclassified to gain or loss | (44,279) | 141,929
Ending | (30,474) | (3,463)
Gain on valuation of financial assets at fair value through other comprehensive income [member] |  |
Beginning | 52,673 |
Changes in accounting policy | 17,741 |
Increase /decrease | 26,290 |
Ending | 96,704 | 52,673
Gain of valuation on available for sale [member] |  |
Beginning | 52,673 | 54,106
Increase /decrease |  | 54,017
Reclassified to gain or loss |  | (55,450)
Ending |  | 52,673
Exchange differences on translation for foreign operations [member] |  |
Beginning | (17,490) | (10,346)
Increase /decrease | 2,289 | (7,144)
Ending | ₩ (15,201) | ₩ (17,490)

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- Definition The amount of accumulated items of income and expense (including reclassification adjustments) that are not recognised in profit or loss as required or permitted by other IFRSs. [Refer: IFRSs [member]; Other comprehensive income] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The amount of other comprehensive income that will be reclassified to profit or loss, before tax. [Refer: Other comprehensive income] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph IG6 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_IG6&doctype=Implementation%20Guidance -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2018-01-01 -Paragraph 82A -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_82A&doctype=Standard -URIDate 2018-03-16 + Details
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