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Operating Expenses - Summary of Operating Expenses (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Profit (loss) [abstract] |  |  |
Salaries and wages | ₩ 3,974,233 | ₩ 3,845,842 | ₩ 3,568,456
Depreciation | 2,530,252 | 2,674,205 | 2,745,969
Depreciation of right-of-use assets | 452,056 |  |
Amortization of intangible assets | 656,611 | 607,527 | 618,533
Commissions | 1,115,477 | 1,080,168 | 1,085,865
Interconnection charges | 534,025 | 579,613 | 640,612
International interconnection fee | 240,254 | 226,627 | 214,058
Purchase of inventories | 4,453,820 | 4,414,094 | 4,053,693
Changes of inventories | 282,957 | (432,607) | (187,439)
Sales commission | 2,315,731 | 1,942,841 | 2,201,778
Service cost | 1,610,261 | 1,540,869 | 1,428,405
Utilities | 332,816 | 323,411 | 323,313
Taxes and dues | 276,815 | 285,131 | 279,574
Rent | 193,357 | 460,377 | 448,772
Insurance premium | 82,404 | 73,654 | 69,384
Installation fee | 155,178 | 143,669 | 146,783
Advertising expenses | 150,166 | 157,675 | 197,114
Research and development expenses | 165,028 | 176,758 | 168,635
Card service cost | 3,066,766 | 3,112,618 | 3,094,894
Others | 1,290,807 | 1,122,718 | 1,379,438
Total | ₩ 23,879,015 | ₩ 22,335,190 | ₩ 22,477,837

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- Definition The amount of depreciation expense. Depreciation is the systematic allocation of depreciable amounts of tangible assets over their useful lives. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of depreciation of right-of-use assets. [Refer: Depreciation and amortisation expense; Right-of-use assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_a&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of expense relating to fees and commissions. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_85&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of expense arising from purchased insurance. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of miscellaneous other operating expenses. [Refer: Other operating income (expense)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of all operating expenses. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_85&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of expense recognised on rental activities. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_85&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition A class of employee benefits expense that represents wages and salaries. [Refer: Employee benefits expense] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 9 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_9&doctype=Standard -URIDate 2019-03-27 + Details
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