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Financial Income and Costs - Summary of Details of Financial Income (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Profit or loss [abstract]
Interest income	₩ 93,078	₩ 115,686	₩ 70,035
Gain on foreign currency transactions	79,653	24,915	18,766
Gain on foreign currency translation	225,580	12,165	11,280
Gain on settlement of derivatives		8,515	368
Gain on valuation of derivatives	57	109,436	141,512
Others	7,960	25,422	30,899
Total	₩ 406,328	₩ 296,139	₩ 272,860

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- Definition

The amount of income associated with interest and other financing activities of the entity.

+ References

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The gains resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]]

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The net gain arising from foreign exchange differences. [Refer: Foreign exchange gain (loss)]

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