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Segment Information - Summary of Segment Information (Detail) - KRW (₩) ₩ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | ₩ 23,436,050 | ₩ 23,546,929 | ₩ 23,164,202
Operating income (loss) | 1,100,860 | 1,069,092 | 1,383,104
Depreciation and Amortization | 3,281,732 | 3,364,502 | 3,345,266
Operating segments [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 27,172,293 | 27,217,843 | 26,742,436
Operating income (loss) | 1,153,167 | 1,112,554 | 1,421,977
Depreciation and Amortization | 3,274,769 | 3,356,126 | 3,337,353
Operating segments [member] | Marketing/Customer [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 14,061,629 | 16,242,552 | 16,187,739
Operating income (loss) | 886,515 | 1,018,593 | 1,093,377
Depreciation and Amortization | 2,293,809 | 2,895,930 | 2,870,161
Operating segments [member] | Finance [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 3,560,417 | 3,637,917 | 3,577,549
Operating income (loss) | 145,463 | 205,678 | 208,566
Depreciation and Amortization | 22,504 | 28,827 | 28,868
Operating segments [member] | Satellite TV [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 690,821 | 685,822 | 668,945
Operating income (loss) | 66,735 | 75,373 | 79,987
Depreciation and Amortization | 98,310 | 99,216 | 98,895
Operating segments [member] | Corporate customer business [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 2,509,880 |  |
Operating income (loss) | 208,584 |  |
Depreciation and Amortization | 546,635 |  |
Operating segments [member] | Others [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | 6,349,546 | 6,651,552 | 6,308,203
Operating income (loss) | (154,130) | (187,090) | 40,047
Depreciation and Amortization | 313,511 | 332,153 | 339,429
Elimination [member] |  |  |
Disclosure of operating segments [Line Items] |  |  |
Operating revenues | (3,736,243) | (3,670,914) | (3,578,234)
Operating income (loss) | (52,307) | (43,462) | (38,873)
Depreciation and Amortization | ₩ 6,963 | ₩ 8,376 | ₩ 7,913

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