Financial Risk - Fair Value and Carrying Amount of Financial Assets and Liabilities Including Fair Value Hierarchy (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disclosure of detailed information about financial instruments [Line items]
Borrowings	₩ 2,184,996		₩ 382,817
Debentures	7,466,852		7,086,187
Assets	7,110,730	₩ (11,997)	7,461,181
Derivative financial liabilities	4,184		39,470
Financial liabilities	16,800,116		12,725,704
Measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
FVTPL	820,366		328,314
Derivatives hedging instruments	39,871		21,902
FVOCI	544,643
Available-for-sale financial assets			734,487
Assets	1,404,880		1,084,703
FVTPL	61,813		60,278
Derivative financial liabilities	4,184		39,470
Financial liabilities	65,997		99,748
Not measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
Borrowings	2,378,843		383,748
Debentures	7,868,472		7,325,370
Long-term payables - other	2,469,653		1,766,451
Financial liabilities	12,716,968		9,475,569
Carrying amount [member] \| Measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
FVTPL	820,366		328,314
Derivatives hedging instruments	39,871		21,902
FVOCI	544,643
Available-for-sale financial assets			734,487
Assets	1,404,880		1,084,703
FVTPL	61,813		60,278
Derivative financial liabilities	4,184		39,470
Financial liabilities	65,997		99,748
Carrying amount [member] \| Not measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
Borrowings	2,184,996		382,817
Debentures	7,405,039		7,025,909
Long-term payables - other	2,393,027		1,649,466
Financial liabilities	11,983,062		9,058,192
Level 1 [member] \| Measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
FVOCI	293,925
Available-for-sale financial assets			589,202
Assets	293,925		589,202
Level 2 [member] \| Measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
FVTPL	695,992		106,057
Derivatives hedging instruments	39,871		21,902
Available-for-sale financial assets			47,383
Assets	735,863		175,342
FVTPL	61,813		60,278
Derivative financial liabilities	4,184		39,470
Financial liabilities	65,997		99,748
Level 2 [member] \| Not measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
Borrowings	2,378,843		383,748
Debentures	7,868,472		7,325,370
Long-term payables - other	2,469,653		1,766,451
Financial liabilities	12,716,968		9,475,569
Level 3 [member] \| Measured at fair value [member]
Disclosure of detailed information about financial instruments [Line items]
FVTPL	124,374		222,257
FVOCI	250,718
Available-for-sale financial assets			97,902
Assets	₩ 375,092		₩ 320,159

The amount of derivative financial assets held for hedging. [Refer: Derivative financial assets]

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The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

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The amount of financial assets at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets; Other comprehensive income]

+ References

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The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]

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The amount of non-derivative financial assets that are designated as available for sale or are not classified as (a) loans and receivables; (b) held-to-maturity investments; or (c) financial assets at fair value through profit or loss. [Refer: Derivative financial assets; Financial assets at fair value through profit or loss; Held-to-maturity investments]

+ References

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The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

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The amount of financial liabilities that meet either of the following conditions: (a) they meet the definition of held for trading; or (b) upon initial recognition they are designated by the entity as at fair value through profit or loss. An entity may use this designation only when permitted by paragraph 4.3.5 of IFRS 9 (embedded derivatives) or when doing so results in more relevant information, because either: (a) it eliminates or significantly reduces a measurement or recognition inconsistency (sometimes referred to as ‘an accounting mismatch’) that would otherwise arise from measuring assets or liabilities or recognising the gains and losses on them on different bases; or (b) a group of financial liabilities or financial assets and financial liabilities is managed and its performance is evaluated on a fair value basis, in accordance with a documented risk management or investment strategy, and information about the group is provided internally on that basis to the entity’s key management personnel (as defined in IAS 24). [Refer: At fair value [member]; Key management personnel of entity or parent [member]; Derivatives [member]; Financial assets; Financial liabilities]

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The amount of notes and debentures issued by the entity.

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Long-term payables including current installments, other.

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Short-term and long-term borrowings.

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