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Investments in Associates and Joint Ventures - Summary of Changes in Investments in Associates and Joint Ventures (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Disclosure of associates and joint ventures [line items] |  |
Beginning | ₩ 284,075 | ₩ 270,029
Acquisition (Disposal) | (19,018) | 29,052
Share of net profit from associates and joint ventures | (15,480) | 2,547
Impairment | (3,662) | (17,128)
Others | 33,516 | (425)
Ending | 279,431 | 284,075
Korea Information & Technology Fund [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 134,969 | 127,583
Share of net profit from associates and joint ventures | 4,275 | 7,446
Others | 290 | (60)
Ending | 139,534 | 134,969
KT-SB Venture Investment [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 4,736 | 4,861
Acquisition (Disposal) | (1,069) |
Share of net profit from associates and joint ventures | (725) | (125)
Ending | 2,942 | 4,736
Mongolian Telecommunications [Member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 6,244 | 7,483
Share of net profit from associates and joint ventures | (348) | 32
Others | (5,896) | (1,271)
Ending |  | 6,244
KT Wibro Infra Co., Ltd. [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 52,200 | 69,328
Acquisition (Disposal) | (52,200) |
Impairment |  | (17,128)
Ending |  | 52,200
KT-CKP New Media Investment Fund [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 4,454 | 3,860
Acquisition (Disposal) | (2,970) |
Share of net profit from associates and joint ventures | 810 | 594
Ending | 2,294 | 4,454
Others [Member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 81,472 | 56,914
Acquisition (Disposal) | 3,178 | 29,052
Share of net profit from associates and joint ventures | (1,952) | (5,400)
Impairment | (3,662) |
Others | 6,313 | 906
Ending | 81,728 | 81,472
KT-IBKC future investment fund [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Beginning | 3,621 |
Acquisition (Disposal) | 7,500 |
Share of net profit from associates and joint ventures | (296) |
Ending | 10,825 | ₩ 3,621
K Bank Inc. [member] |  |
Disclosure of associates and joint ventures [line items] |  |
Acquisition (Disposal) | 26,543 |
Share of net profit from associates and joint ventures | (17,244) |
Others | 32,809 |
Ending | ₩ 42,108 |

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- Definition The amount of investments in subsidiaries, joint ventures and associates in an entity's separate financial statements. [Refer: Associates [member]; Joint ventures [member]; Subsidiaries [member]; Investments in subsidiaries] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_55&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The entity's share of the profit (loss) from continuing operations of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Continuing operations [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss) from continuing operations] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2017-01-01 -Paragraph B16 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_B16_a&doctype=Appendix&seq=2 -URIDate 2017-03-09 + Details
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- Definition Acquisition (disposal) of investments in subsidiaries, joint ventures and associates. + References No definition available. + Details
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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information about associate and joint ventures associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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