POSCO (PKX) 20-F 30 Apr 19 2018 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Dec. 31, 2018shares
Document and entity information [abstract]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	PKX
Entity Registrant Name	POSCO
Entity Central Index Key	0000889132
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	80,001,132

Consolidated Statements of Fina

Consolidated Statements of Financial Position - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	₩ 2,643,865	₩ 2,612,530
Trade accounts and notes receivable, net	9,130,204	8,824,563
Other receivables, net	1,385,629	1,636,006
Other short-term financial assets	8,081,096	7,045,880
Inventories	12,153,303	10,793,781
Current income tax assets	51,557	38,489
Assets held for sale	21,854	71,768
Other current assets	684,464	821,242
Total current assets	34,151,972	31,844,259
Long-term trade accounts and notes receivable, net	427,125	731,570
Other receivables, net	863,240	879,176
Other long-term financial assets	1,647,898	1,911,684
Investments in associates and joint ventures	3,650,003	3,557,932
Investment property, net	928,615	1,064,914
Property, plant and equipment, net	30,018,273	31,883,535
Intangible assets, net	5,170,825	5,952,269
Defined benefit assets, net	1,489	8,224
Deferred tax assets	1,408,787	1,463,055
Other non-current assets	508,764	489,011
Total non-current assets	44,625,019	47,941,370
Total assets	78,776,991	79,785,629
Liabilities
Trade accounts and notes payable	4,006,135	3,465,146
Short-term borrowings and current installments of long-term borrowings	10,289,619	11,274,516
Other payables	1,720,097	1,753,461
Other short-term financial liabilities	77,800	129,812
Current income tax liabilities	948,166	515,538
Provisions	298,453	110,946
Other current liabilities	2,090,307	2,240,919
Total current liabilities	19,430,577	19,490,338
Long-term trade accounts and notes payable	29,825	12,532
Long-term borrowings, excluding current installments	9,919,651	9,789,141
Other payables	148,868	147,750
Other long-term financial liabilities	64,162	114,105
Defined benefit liabilities, net	140,933	137,193
Deferred tax liabilities	1,688,893	1,904,242
Long-term provisions	431,036	477,172
Other non-current liabilities	250,432	386,431
Total non-current liabilities	12,673,800	12,968,566
Total liabilities	32,104,377	32,458,904
Equity
Share capital	482,403	482,403
Capital surplus	1,420,007	1,422,021
Hybrid bonds	199,384	996,919
Reserves	(1,404,368)	(682,556)
Treasury shares	(1,532,728)	(1,533,054)
Retained earnings	44,160,659	42,974,658
Equity attributable to owners of the controlling company	43,325,357	43,660,391
Non-controllinginterests	3,347,257	3,666,334
Total equity	46,672,614	47,326,725
Total liabilities and equity	₩ 78,776,991	₩ 79,785,629

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of comprehensive income [abstract]
Revenue	₩ 65,154,636	₩ 60,186,867	₩ 52,939,771
Cost of sales	(57,129,060)	(51,915,597)	(46,271,465)
Gross profit	8,025,576	8,271,270	6,668,306
Selling and administrative expenses
Impairment loss on trade accounts and notes receivable	(74,781)	(173,694)	(165,150)
Other administrative expenses	(1,985,755)	(2,003,106)	(2,126,390)
Selling expenses	(369,245)	(1,557,277)	(1,553,686)
Other operating income and expenses
Impairment loss on other receivables	(63,092)	(98,177)	(37,567)
Other operating income	523,586	448,481	202,478
Other operating expenses	(2,014,462)	(691,376)	(705,495)
Operating profit	4,041,827	4,196,121	2,282,496
Share of profit (loss) of equity-accounted investees, net	112,635	10,540	(88,677)
Finance income and costs
Finance income	1,705,970	2,372,667	2,231,980
Finance costs	(2,244,416)	(2,484,277)	(3,014,190)
Profit before income taxes	3,616,016	4,095,051	1,411,609
Income tax expense	(1,683,630)	(1,185,740)	(379,544)
Profit	1,932,386	2,909,311	1,032,065
Items that will not be reclassified subsequently to profit or loss :
Remeasurements of defined benefit plans	(173,489)	(47,543)	20,540
Net changes in fair value of equity investments at fair value through other comprehensive income	(149,188)
Items that are or may be reclassified subsequently to profit or loss :
Capital adjustment arising from investments in equity-method investees	(62,732)	(217,388)	134,590
Net changes in unrealized fair value of available-for-sale investments		(31,389)	310,608
Foreign currency translation differences	(42,908)	(264,695)	(11,491)
Gain or losses on valuation of derivatives	(212)	(143)
Other comprehensive income (loss), net of tax	(428,529)	(561,158)	454,247
Total comprehensive income	1,503,857	2,348,153	1,486,312
Profit attributable to :
Owners of the controlling company	1,711,902	2,756,230	1,354,807
Non-controllinginterests	220,484	153,081	(322,742)
Profit	1,932,386	2,909,311	1,032,065
Total comprehensive income attributable to :
Owners of the controlling company	1,292,785	2,184,402	1,814,030
Non-controllinginterests	211,072	163,751	(327,718)
Total comprehensive income	₩ 1,503,857	₩ 2,348,153	₩ 1,486,312
Basic and diluted earnings per share (in Won)	₩ 21,177	₩ 34,040	₩ 16,521

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - KRW (₩) ₩ in Millions	Total	Final dividends [member]	Interim dividends [member]	Share capital [member]	Capital surplus [member]	Hybrid bonds [member]	Reserves [member]	Treasury shares [member]	Retained earnings [member]	Retained earnings [member]Final dividends [member]	Retained earnings [member]Interim dividends [member]	Attributable to owners of the controlling company [member]	Attributable to owners of the controlling company [member]Final dividends [member]	Attributable to owners of the controlling company [member]Interim dividends [member]	Non-controlling interests [member]	Non-controlling interests [member]Final dividends [member]
Beginning balance at Dec. 31, 2015	₩ 45,013,201			₩ 482,403	₩ 1,393,079	₩ 996,919	₩ (594,756)	₩ (1,533,898)	₩ 40,461,496			₩ 41,205,243			₩ 3,807,958
Comprehensive income (loss):
Profit	1,032,065								1,354,807			1,354,807			(322,742)
Other comprehensive income (loss)
Remeasurements of defined benefit plans, net of tax	20,540								9,787			9,787			10,753
Capital adjustment arising from investments in equity-accounted investees, net of tax	134,590						124,626					124,626			9,964
Net changes in the unrealized fair value of available-for-sale investments, net of tax	310,608						314,428					314,428			(3,820)
Foreign currency translation differences, net of tax	(11,491)						10,382					10,382			(21,873)
Total comprehensive income	1,486,312						449,436		1,364,594			1,814,030			(327,718)
Transactions with owners of the controlling company, recognized directly in equity:
Dividends		₩ (530,307)	₩ (179,992)							₩ (479,974)	₩ (179,992)		₩ (479,974)	₩ (179,992)		₩ (50,333)
Changes in subsidiaries	49,250														49,250
Changes in ownership interests in subsidiaries	(7,894)				8,650							8,650			(16,544)
Interest of hybrid bonds	(68,085)								(43,832)			(43,832)			(24,253)
Disposal of treasury shares	462				32			430				462
Others	2,322				5,486		1,335		3,420			10,241			(7,919)
Total transactions with owners of the controlling company	(734,244)				14,168		1,335	430	(700,378)			(684,445)			(49,799)
Ending balance at Dec. 31, 2016	45,765,269			482,403	1,407,247	996,919	(143,985)	(1,533,468)	41,125,712			42,334,828			3,430,441
Comprehensive income (loss):
Profit	2,909,311								2,756,230			2,756,230			153,081
Other comprehensive income (loss)
Remeasurements of defined benefit plans, net of tax	(47,543)								(38,043)			(38,043)			(9,500)
Capital adjustment arising from investments in equity-accounted investees, net of tax	(217,388)						(214,794)					(214,794)			(2,594)
Net changes in the unrealized fair value of available-for-sale investments, net of tax	(31,389)						(45,953)					(45,953)			14,564
Foreign currency translation differences, net of tax	(264,695)						(272,902)					(272,902)			8,207
Gain or losses on valuation of derivatives, net of tax	(143)						(136)					(136)			(7)
Total comprehensive income	2,348,153						(533,785)		2,718,187			2,184,402			163,751
Transactions with owners of the controlling company, recognized directly in equity:
Dividends		(502,896)	(359,993)							(459,987)	(359,993)		(459,987)	(359,993)		(42,909)
Changes in subsidiaries	(7,151)														(7,151)
Changes in ownership interests in subsidiaries	163,707				16,287							16,287			147,420
Interest of hybrid bonds	(67,787)								(43,600)			(43,600)			(24,187)
Disposal of treasury shares	540				126			414				540
Others	(13,117)				(1,639)		(4,786)		(5,661)			(12,086)			(1,031)
Total transactions with owners of the controlling company	(786,697)				14,774		(4,786)	414	(869,241)			(858,839)			72,142
Ending balance (Adjusted balance [member]) at Dec. 31, 2017	47,110,638			482,403	1,422,021	996,919	(1,181,073)	(1,533,054)	43,350,819			43,538,035			3,572,603
Ending balance at Dec. 31, 2017	47,326,725			482,403	1,422,021	996,919	(682,556)	(1,533,054)	42,974,658			43,660,391			3,666,334
Adjustment on initial application of IFRS No. 15, net of tax	(129,883)								(70,906)			(70,906)			(58,977)
Adjustment on initial application of IFRS No. 9, net of tax	(86,204)						(498,517)		447,067			(51,450)			(34,754)
Comprehensive income (loss):
Profit	1,932,386								1,711,902			1,711,902			220,484
Other comprehensive income (loss)
Remeasurements of defined benefit plans, net of tax	(173,489)								(145,488)			(145,488)			(28,001)
Capital adjustment arising from investments in equity-accounted investees, net of tax	(62,732)						(76,587)					(76,587)			13,855
Net changes in fair value of equity investments at fair value through other comprehensive income, net of tax	(149,188)						(104,293)		(46,883)			(151,176)			1,988
Foreign currency translation differences, net of tax	(42,908)						(45,650)					(45,650)			2,742
Gain or losses on valuation of derivatives, net of tax	(212)						(216)					(216)			4
Total comprehensive income	1,503,857						(226,746)		1,519,531			1,292,785			211,072
Transactions with owners of the controlling company, recognized directly in equity:
Dividends		₩ (334,239)	₩ (400,003)							₩ (279,999)	₩ (400,003)		₩ (279,999)	₩ (400,003)		₩ (54,240)
Changes in subsidiaries	(2,092)														(2,092)
Changes in ownership interests in subsidiaries	(2,151)				(1,497)							(1,497)			(654)
Repayment of hybrid bonds	(1,159,322)				(2,769)	(797,535)						(800,304)			(359,018)
Interest of hybrid bonds	(42,891)								(24,443)			(24,443)			(18,448)
Disposal of treasury shares	459				133			326				459
Others	(1,642)				2,119		3,451		(5,246)			324			(1,966)
Total transactions with owners of the controlling company	(1,941,881)				(2,014)	(797,535)	3,451	326	(709,691)			(1,505,463)			(436,418)
Ending balance at Dec. 31, 2018	₩ 46,672,614			₩ 482,403	₩ 1,420,007	₩ 199,384	₩ (1,404,368)	₩ (1,532,728)	₩ 44,160,659			₩ 43,325,357			₩ 3,347,257

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Profit	₩ 1,932,386	₩ 2,909,311	₩ 1,032,065
Adjustments for:
Depreciation	2,911,048	2,887,646	2,835,843
Amortization	356,581	409,774	378,004
Finance income	(737,745)	(1,376,324)	(882,905)
Finance costs	1,168,225	1,440,282	1,501,953
Income tax expense	1,683,630	1,185,740	379,544
Gain on disposal of property, plant and equipment	(53,139)	(32,145)	(23,826)
Loss on disposal of property, plant and equipment	117,614	151,343	86,622
Impairment losses on property, plant and equipment	1,004,704	117,231	196,882
Gain on disposal of investments in subsidiaries, associates and joint ventures	(45,241)	(81,794)	(23,305)
Loss on disposal of investments in subsidiaries, associates and joint ventures	5,226	19,985	22,499
Share of loss (profit) of equity-accounted investees	(112,635)	(10,540)	88,677
Expenses related to post-employment benefits	216,489	199,926	333,139
Increase to provisions	240,146	215,383	189,914
Impairment loss on trade and other receivables	137,873	271,871	202,717
Loss on valuation of inventories	141,799	78,560	152,249
Gain on disposal of intangible assets	(117,139)	(22,391)	(671)
Impairment losses on goodwill and intangible assets	337,519	167,995	127,875
Gain on disposal of assets held for sale	(27,171)	(1,180)	(23,112)
Impairment losses on assets held for sale	50,829		24,890
Others, net	77,945	(10,093)	8,804
Adjustments to reconcile profit (loss) other than changes in working capital	7,356,558	5,611,269	5,575,793
Changes in operating assets and liabilities	(2,105,726)	(1,841,633)	(404,570)
Interest received	352,337	244,980	206,839
Interest paid	(750,410)	(735,735)	(691,264)
Dividends received	224,410	225,514	152,559
Income taxes paid	(1,139,830)	(806,396)	(602,004)
Net cash provided by operating activities	5,869,725	5,607,310	5,269,418
Cash flows from investing activities
Acquisitions of short-term financial instruments	(32,173,134)	(20,843,530)	(18,578,809)
Proceeds from disposal of short-term financial instruments	31,105,544	19,146,634	17,177,409
Increase in loans	(627,783)	(1,055,895)	(603,332)
Collection of loans	941,962	667,045	557,064
Acquisitions of securities	(321,916)
Acquisitions of available-for-sale investments		(66,278)	(328,151)
Proceeds from disposal of securities	221,646
Proceeds from disposal of available-for-sale investments		1,006,856	280,066
Acquisitions of investments in associates and joint ventures	(47,355)	(60,277)	(173,769)
Proceeds from disposal of investments in associates and joint ventures	88,852	74,881	7,914
Acquisitions of property, plant and equipment	(2,135,550)	(2,287,580)	(2,324,112)
Proceeds from disposal of property, plant and equipment	90,412	39,183	44,330
Acquisitions of investment property	(44,106)	(69,169)	(45,735)
Proceeds from disposal of investment property	70,817	5,771	11,624
Acquisitions of intangible assets	(447,616)	(343,423)	(138,181)
Proceeds from disposal of intangible assets	77,654	28,502	8,672
Proceeds from disposal of assets held for sale	93,338	203,958	305,813
Increase in cash from (payment for) acquisition of business, net of cash acquired		(174,165)	4,503
Cash received (decrease in cash) from disposal of business, net of cash transferred	447,917	(53,008)	21,223
Others, net	11,348	(37,379)	18,844
Net cash used in investing activities	(2,647,970)	(3,817,874)	(3,754,627)
Cash flows from financing activities
Proceeds from borrowings	2,762,446	1,725,983	1,988,665
Repayment of borrowings	(3,136,308)	(3,136,016)	(4,274,895)
Proceeds from (repayment of) short-term borrowings, net	(854,554)	558,083	(885,861)
Payment of cash dividends	(723,934)	(863,450)	(708,970)
Payment of interest of hybrid bonds	(46,166)	(67,783)	(68,097)
Repayment of hybrid bonds	(1,160,000)
Capital contribution from non-controlling interests and proceeds from disposal of subsidiary while maintaining control	5,808	266,219	24,704
Capital deduction from non-controlling interests and additional acquisition of interests in subsidiaries	(3,823)	(26,288)	(11,301)
Others, net	(38,517)	(22,276)	(15,212)
Net cash used in financing activities	(3,195,048)	(1,565,528)	(3,950,967)
Effect of exchange rate fluctuation on cash held	4,628	(58,997)	12,611
Net increase (decrease) in cash and cash equivalents	31,335	164,911	(2,423,565)
Cash and cash equivalents at beginning of the period	2,612,530	2,447,619	4,871,184
Cash and cash equivalents at end of the period	₩ 2,643,865	₩ 2,612,530	₩ 2,447,619

General Information

General Information	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
General Information	1. General Information General information about POSCO, its 36 domestic subsidiaries including POSCO ENGINEERING & CONSTRUCTION CO., LTD., 136 foreign subsidiaries including POSCO America Corporation (collectively “the Company”) and its 126 associates and joint ventures are as follows: (a) The controlling company POSCO, the controlling company, was incorporated on April 1, 1968, under the Commercial Code of the Republic of Korea to manufacture and sell steel rolled products and plates in the domestic and foreign markets. The shares of POSCO have been listed on the Korea Exchange since June 10, 1988. POSCO owns and operates two steel plants (Pohang and Gwangyang) and one office in Korea and it also operates internationally through six of its overseas liaison offices. As of December 31, 2018, POSCO’s shareholders are as follows: Shareholder’s name Number of shares Ownership (%) National Pension Service 9,342,192 10.72 BlackRock Fund Advisors (*1,2,3) 4,549,553 5.22 Nippon Steel & Sumitomo Metal Corporation (*1) 2,894,712 3.32 GIC Private Limited 2,016,887 2.31 KB Financial Group Inc. and subsidiaries (*2) 2,001,820 2.30 Others 66,381,671 76.13 87,186,835 100.00 (*1) Includes American Depository Receipts (ADRs) of POSCO, each of which represents 0.25 share of POSCO’s common share which has par value of ￦ (*2) Includes shares held by subsidiaries and others. (*3) The number of shares held by the shareholder based on the information in the status report of large-scale shareholders filed with Korea Exchange on October 4, 2018. As of December 31, 2018, the shares of POSCO are listed on the Korea Exchange, while its ADRs are listed on the New York Stock Exchange. (b) Consolidated subsidiaries Details of consolidated subsidiaries as of December 31, 2017 and 2018 are as follows: Principal operations Ownership (%) December 31, 2017 December 31, 2018 POSCO Subsidiaries Total POSCO Subsidiaries Total Region [Domestic] POSCO ENGINEERING & CONSTRUCTION., CO., LTD. Engineering and construction 52.80 — 52.80 52.80 — 52.80 Pohang POSCO Processing & Service Steel sales and trading 93.95 0.45 94.40 93.95 0.45 94.40 Seoul POSCO COATED & COLOR STEEL Co., Ltd. Coated steel manufacturing 56.87 — 56.87 56.87 — 56.87 Pohang POSCO ICT Computer hardware and software distribution 65.38 — 65.38 65.38 — 65.38 Pohang POSCO Research Institute Economic research and consulting 100.00 — 100.00 100.00 — 100.00 Seoul POSMATE Business facility maintenance 83.83 16.17 100.00 59.80 40.20 100.00 Seoul POSCO A&C Architecture and consulting 100.00 — 100.00 100.00 — 100.00 Seoul POSCO Venture Capital Co., Ltd. Investment in venture companies 95.00 — 95.00 95.00 — 95.00 Pohang eNtoB Corporation Electronic commerce 7.50 53.63 61.13 7.50 53.63 61.13 Seoul POSCO CHEMTECH Refractories manufacturing and sales 60.00 — 60.00 60.00 — 60.00 Pohang POSCO-Terminal Co., Ltd. Transporting and warehousing 51.00 — 51.00 51.00 — 51.00 Gwangyang POSCO M-TECH Packing materials manufacturing and sales 48.85 — 48.85 48.85 — 48.85 Pohang POSCO ENERGY CO., LTD. Generation of electricity 89.02 — 89.02 89.02 — 89.02 Seoul POSCO NIPPON STEEL RHF JOINT VENTURE.CO., Ltd. Steel byproduct manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Pohang MegaAsset Co., Ltd. Real estate rental and sales — 100.00 100.00 — 100.00 100.00 Incheon Future Creation Fund Postech Early Stage account Investment in venture companies — 40.00 40.00 — 40.00 40.00 Seoul POSCO WOMAN’S FUND Investment in venture companies — 40.00 40.00 — 40.00 40.00 Seoul SPH Co, Ltd. House manufacturing and management — 100.00 100.00 — 100.00 100.00 Incheon Posco Group University Education service and real estate business 100.00 — 100.00 100.00 — 100.00 Incheon HOTEL LAONZENA Hotel business — 100.00 100.00 — 100.00 100.00 Daegu Growth Ladder POSCO K-Growth Investment in venture companies — 50.00 50.00 — 50.00 50.00 Pohang 2015 POSCO New technology II Fund Investment in venture companies — 25.00 25.00 — 25.00 25.00 Pohang Posco e&c Songdo International Building Non-residential — 100.00 100.00 — 100.00 100.00 Seoul POSCO ES MATERIALS CO., Ltd. Secondary and storage battery manufacturing 75.32 — 75.32 90.00 — 90.00 Gumi POSCO Research & Technology Intellectual Property Services and consulting 100.00 — 100.00 100.00 — 100.00 Seoul Poscoene Refuse derived fuel and power generation — 100.00 100.00 — 100.00 100.00 Seoul POSCO Humans Construction 90.30 — 90.30 90.30 — 90.30 Pohang Mapo Hibroad Parking Co., Ltd. Construction — 71.00 71.00 — 71.00 71.00 Seoul BLUE O&M Co., Ltd. Engineering service — 100.00 100.00 — 100.00 100.00 Pohang Busan E&E Co., Ltd. Refuse derived fuel and power generation 70.00 — 70.00 70.00 — 70.00 Busan POSCO Family Strategy Fund Investment in venture companies 69.91 30.09 100.00 69.91 30.09 100.00 Pohang POSCO DAEWOO Corporation Trading, energy & resource development and others 62.90 0.04 62.94 62.90 0.04 62.94 Seoul Pohang Scrap Recycling Distribution Center Co., Ltd. Steel processing and sales — 51.00 51.00 — 51.00 51.00 Pohang PSC Energy Global Co., Ltd. Investment in energy industry — 100.00 100.00 — 100.00 100.00 Pohang Suncheon Eco Trans Co., Ltd Train manufacturing and management 100.00 — 100.00 100.00 — 100.00 Suncheon Songdo Development PMC (Project Management Company) LLC. Housing business agency — — — — 100.00 100.00 Incheon POSPower Co., Ltd. (*1) Generation of electricity — 100.00 100.00 — — — Samcheok POCA STEM Co., Ltd. Stem cell medicine development — 100.00 100.00 — — — Seoul Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 Private equity trust 97.47 — 97.47 — — — Seoul Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust Private equity trust 99.01 — 99.01 — — — Seoul Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 Private equity trust — 99.67 99.67 — — — Seoul [Foreign] POSCO America Corporation Steel trading 99.45 0.55 100.00 99.45 0.55 100.00 USA POSCO AUSTRALIA PTY LTD Raw material sales & mine development 100.00 — 100.00 100.00 — 100.00 Australia POSCO Canada Ltd. Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCAN Elkview Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCO Asia Co., Ltd. Steel and raw material trading 100.00 — 100.00 100.00 — 100.00 China POSCO-CTPC Co., Ltd. Steel manufacturing and sales 56.60 43.40 100.00 61.91 38.09 100.00 China POSCO E&C Vietnam Co., Ltd. Steel structure manufacturing and sales — 100.00 100.00 — 100.00 100.00 Vietnam Zhangjiagang Pohang Stainless Steel Co., Ltd. Stainless steel manufacturing and sales 58.60 23.88 82.48 58.60 23.88 82.48 China POSCO(Guangdong) Coated Steel Co., Ltd. Plating steel sheet manufacturing and sales 87.04 10.04 97.08 87.04 10.04 97.08 China POSCO (Thailand) Company Limited Steel manufacturing and sales 88.58 11.42 100.00 88.58 11.42 100.00 Thailand Myanmar POSCO Steel Co., Ltd Zinc relief manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Myanmar POSCO-MKPC SDN BHD Steel manufacturing and sales 44.69 25.31 70.00 44.69 25.31 70.00 Malaysia Qingdao Pohang Stainless Steel Co., Ltd. Stainless steel manufacturing and sales 70.00 30.00 100.00 70.00 30.00 100.00 China POSCO(Suzhou) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO-China Qingdao Processing Center Co., Ltd. Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 China POS-ORE Iron ore sales and sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-China Holding Corp. Holding company 100.00 — 100.00 100.00 — 100.00 China POSCO JAPAN Co., Ltd. Steel trading 100.00 — 100.00 100.00 — 100.00 Japan POS-CD Coal sales — 100.00 100.00 — 100.00 100.00 Australia POS-GC Coal sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-India Private Limited Steel manufacturing and sales 99.99 — 99.99 99.99 — 99.99 India POSCO-India Pune Processing Center. Pvt. Ltd. Steel manufacturing and sales 65.00 — 65.00 65.00 — 65.00 India POSCO Japan PC CO., LTD Steel manufacturing and sales — 86.12 86.12 — 86.12 86.12 Japan POSCO-CFPC Co., Ltd. Steel manufacturing and sales 39.60 60.40 100.00 39.60 60.40 100.00 China POSCO E&C CHINA Co., Ltd. Civil engineering and construction — 100.00 100.00 — 100.00 100.00 China POSCO MPPC S.A. de C.V. Steel manufacturing and sales 21.02 75.29 96.31 21.02 75.29 96.31 Mexico Zhangjigang Pohang Port Co., Ltd. Loading and unloading service — 100.00 100.00 — 100.00 100.00 China POSCO-VIETNAM Co., Ltd. Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Vietnam POSCO MEXICO S.A. DE C.V. Automotive steel sheet manufacturing and sales 84.84 15.16 100.00 83.28 14.88 98.16 Mexico POSCO-Poland Wroclaw Processing Center Sp. z o. o. Steel manufacturing and sales 60.00 — 60.00 60.00 — 60.00 Poland POS-NP Coal sales — 100.00 100.00 — 100.00 100.00 Australia POSCO DAEWOO WAIGAIQIAO SHANGHAI CO., LTD Intermediary trade & bonded warehouse operation — 100.00 100.00 — 100.00 100.00 China PT. Bio Inti Agrindo Forest resources development — 85.00 85.00 — 85.00 85.00 Indonesia POSCO ENGINEERING AND CONSTRUCTION AUSTRALIA Iron ore development and sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-TISCO (JILIN) PROCESSING CENTER Co., Ltd. Steel manufacturing and sales 50.00 10.00 60.00 50.00 10.00 60.00 China POSCO Thainox Public Company Limited STS cold-rolled steel manufacturing and sales 84.88 — 84.88 84.66 — 84.66 Thailand Hunchun Posco Hyundai Logistics Logistics — 80.00 80.00 — 80.00 80.00 China POSCO DAEWOO VIETNAM CO., LTD Trading business — 100.00 100.00 — 100.00 100.00 Vietnam POSCO(Chongqing) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China SUZHOU POSCO-CORE TECHNOLOGY CO., LTD. Component manufacturing and sales — 100.00 100.00 — 100.00 100.00 China PT.Krakatau Posco Chemtech Calcination Quicklime manufacturing and sales — 80.00 80.00 — 80.00 80.00 Indonesia POSCO AFRICA (PROPRIETARY) LIMITED Mine development 100.00 — 100.00 100.00 — 100.00 South POSCO ICT BRASIL IT service and engineering — 100.00 100.00 — 100.00 100.00 Brazil LA-SRDC Scrap manufacturing — 100.00 100.00 — 100.00 100.00 USA POSCO Center Beijing Real estate development, rental and management — 100.00 100.00 — 100.00 100.00 China POSCO AMERICA COMERCIALIZADORA S DE RL DE CV Human resource service — 100.00 100.00 — 100.00 100.00 Mexico POSCO(Guangdong) Automotive Steel Co., Ltd. Steel manufacturing and sales 83.64 10.00 93.64 83.64 10.00 93.64 China POSCO-Malaysia SDN. BHD. Steel manufacturing and sales 81.79 13.63 95.42 81.79 13.63 95.42 Malaysia PT KRAKATAU BLUE WATER Wastewater treatment facilities operation and maintenance — 67.00 67.00 — 67.00 67.00 Indonesia POSCO DAEWOO MYANMAR CORPORATION LIMITED Trading business — 100.00 100.00 — 100.00 100.00 Myanmar POSCO-Italy Processing Center Stainless steel sheet manufacturing and sales 80.00 10.00 90.00 80.00 10.00 90.00 Italy POSCO DAEWOO E&P CANADA CORPORATION Crude oil and natural gas mining — 100.00 100.00 — 100.00 100.00 Canada Myanmar POSCO C&C Company, Limited. Steel manufacturing and sales — 70.00 70.00 — 70.00 70.00 Myanmar POSCO ICT VIETNAM IT service and electric control engineering — 100.00 100.00 — 100.00 100.00 Vietnam Daewoo Global Development. Pte., Ltd Real estate development — 81.51 81.51 — 81.51 81.51 Myanmar Myanmar POSCO Engineering & Construction Company, Limited. Construction and engineering service — 100.00 100.00 — 100.00 100.00 Myanmar POS-Minerals Mine development management and sales — 100.00 100.00 — 100.00 100.00 USA POSCO(Wuhu) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 68.57 31.43 100.00 68.57 31.43 100.00 China POSCO Engineering and Construction India Private Limited Civil engineering and construction — 100.00 100.00 — 100.00 100.00 India POSCO COATED STEEL (THAILAND) CO., LTD. Automotive steel sheet manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Thailand Daewoo Amara Company Limited Real estate development — 85.00 85.00 — 85.00 85.00 Myanmar Daewoo Power and Infra (PTY) Limited Electricity — 100.00 100.00 — 100.00 100.00 South Africa POSMATE-CHINA CO., LTD Business facility maintenance — 100.00 100.00 — 100.00 100.00 China Daewoo Precious Resources Co., Ltd. Resources development — 70.00 70.00 — 70.00 70.00 Myanmar POSCO-Mexico Villagran Wire-rod Steel manufacturing and sales 56.75 10.00 66.75 56.75 10.00 66.75 Mexico POSCO ChengDu Processing Center Steel manufacturing and sales 33.00 10.00 43.00 33.00 10.00 43.00 China POSCO SUZHOU PROCESSING CENTER CO., LTD. Steel manufacturing and sales 30.00 70.00 100.00 30.00 70.00 100.00 China POSCO E&C SMART S DE RL DE CV Civil engineering and construction — 100.00 100.00 — 100.00 100.00 Mexico POSCO Philippine Manila Processing Center, Inc. Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 Philippines POSCO E&C HOLDINGS CO., Ltd. Holding company — 100.00 100.00 — 100.00 100.00 Thailand POSCO E&C (THAILAND) CO., Ltd. Construction and engineering — 100.00 100.00 — 100.00 100.00 Thailand Daewoo Power PNG Ltd. Electricity production — 100.00 100.00 — 100.00 100.00 Papua New PT.Krakatau Posco Social Enterprise Social enterprise — 100.00 100.00 — 100.00 100.00 Indonesia Ventanas Philippines Construction Inc Construction — 100.00 100.00 — 100.00 100.00 Philippines POSCO E&C Mongolia Construction and engineering service — 100.00 100.00 — 100.00 100.00 Mongolia POSCO Gulf SFC LLC Steel manufacturing and sales — 97.76 97.76 — 65.72 65.72 United Arab SANPU TRADING Co., Ltd. Raw material trading — 70.04 70.04 — 70.04 70.04 China Zhangjiagang BLZ Pohang International Trading Steel Intermediate trade — 100.00 100.00 — 100.00 100.00 China POSCO RU Limited Liability Company Trade and business development 100.00 — 100.00 100.00 — 100.00 Russia Golden Lace DAEWOO Company Limited Rice processing — 60.00 60.00 — 60.00 60.00 Myanmar POSCO ICT - IT service and DVR business — 100.00 100.00 — 100.00 100.00 China Pos-Sea Steel Intermediate trade — 100.00 100.00 — 100.00 100.00 Singapore POSCO Europe Steel Distribution Center Logistics & Steel sales 50.00 20.00 70.00 50.00 20.00 70.00 Slovenia POSCO ENGINEERING (THAILAND) CO., LTD. Construction and engineering service — 100.00 100.00 — 100.00 100.00 Thailand POSCO VST CO., LTD. Stainless steel sheet manufacturing and sales 95.65 — 95.65 95.65 — 95.65 Vietnam POSCO DAEWOO UKRAINE LLC Grain sales — 100.00 100.00 — 100.00 100.00 Ukraine Zhangjiagang Pohang Refractories Co., Ltd. Refractory materials sales & furnace maintenance — 51.00 51.00 — 51.00 51.00 China POSCO Maharashtra Steel Private Limited Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 India POSCO INDIA HOLDINGS PRIVATE LIMITED Steel manufacturing and sales 93.34 1.98 95.32 93.34 1.98 95.32 India POSCO TNPC Otomotiv Celik San. Ve Tic. A.S Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Turkey POSCO VIETNAM HOLDINGS CO., LTD Steel manufacturing and sales 83.54 5.29 88.83 83.54 5.29 88.83 Vietnam POSCO(Liaoning) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO-Indonesia Jakarta Processing Center Steel manufacturing and sales 65.00 20.00 85.00 65.00 20.00 85.00 Indonesia PT.MRI Mine development 65.00 — 65.00 65.00 — 65.00 Indonesia POSCO TMC INDIA PRIVATE LIMITED Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 India POSCO-AAPC Steel manufacturing and sales — 97.80 97.80 — 97.80 97.80 USA POSCO(Yantai) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO India Steel Distribution Center Private Ltd. Steel logistics — 100.00 100.00 — 100.00 100.00 India POSCO China Dalian Plate Processing Center Co., Ltd. Plate manufacturing and sales 80.00 10.00 90.00 79.52 11.70 91.22 China POSCO-South Asia Company Limited Steel sales 100.00 — 100.00 100.00 — 100.00 Thailand POSCO SS VINA Co., Ltd Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Vietnam PT.POSCO ICT INDONESIA IT service and electric control engineering — 66.99 66.99 — 66.99 66.99 Indonesia POSCO NCR Coal Ltd. Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCO WA PTY LTD Iron ore sales & mine development 100.00 — 100.00 100.00 — 100.00 Australia POSCO AUSTRALIA GP PTY LIMITED Resource development — 100.00 100.00 — 100.00 100.00 Australia POSCO DAEWOO POWER (PNGPOM) LTD. Electricity production — 100.00 100.00 — 100.00 100.00 Papua New PT. KRAKATAU POSCO ENERGY Electricity production construction and operation — 90.00 90.00 — 90.00 90.00 Indonesia POSCO DAEWOO AMERICA CORP. Trading business — 100.00 100.00 — 100.00 100.00 USA POSCO DAEWOO DEUTSCHLAND GMBH Trading business — 100.00 100.00 — 100.00 100.00 Germany POSCO DAEWOO JAPAN Corp Trading business — 100.00 100.00 — 100.00 100.00 Japan POSCO DAEWOO SINGAPORE PTE LTD. Trading business — 100.00 100.00 — 100.00 100.00 Singapore POSCO DAEWOO ITALIA S.R.L. Trading business — 100.00 100.00 — 100.00 100.00 Italy POSCO DAEWOO CHINA CO., LTD Trading business — 100.00 100.00 — 100.00 100.00 China Daewoo Textile LLC Textile manufacturing — 100.00 100.00 — 100.00 100.00 Uzbekistan POSCO DAEWOO AUSTRALIA HOLDINGS PTY. LTD. Resource development — 100.00 100.00 — 100.00 100.00 Australia POSCO MAURITIUS LIMITED Coal development and sales — 100.00 100.00 — 100.00 100.00 Mauritius PT. KRAKATAU POSCO Steel manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Indonesia POSCO DAEWOO MEXICO S.A. de C.V. Trading business — 100.00 100.00 — 100.00 100.00 Mexico Daewoo International Guangzhou Corp. Trading business — 100.00 100.00 — 100.00 100.00 China POSCO DAEWOO MALAYSIA SDN BHD Trading business — 100.00 100.00 — 100.00 100.00 Malaysia PT.POSCO INDONESIA INTI Mine development 99.99 — 99.99 99.99 — 99.99 Indonesia POSCO DAEWOO SHANGHAI CO., LTD. Trading business — 100.00 100.00 — 100.00 100.00 China PGSF, L.P. Investment in bio tech Industry — 100.00 100.00 — 100.00 100.00 USA POSCO DAEWOO INDIA PVT., LTD. Trading business — 100.00 100.00 — 100.00 100.00 India POSCO(Dalian) IT Center Development Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 China PT. POSCO E&C INDONESIA Civil engineering and construction — 100.00 100.00 — 100.00 100.00 Indonesia HUME COAL PTY LTD Raw material manufacturing — 100.00 100.00 — 100.00 100.00 Australia Brazil Sao Paulo Steel Processing Center Steel manufacturing and sales — 76.00 76.00 — 76.00 76.00 Brazil DAESAN (CAMBODIA) Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 Cambodia POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. Construction — 100.00 100.00 — 100.00 100.00 Brazil POSCO ASSAN TST STEEL INDUSTRY Steel manufacturing and sales 60.00 10.00 70.00 60.00 10.00 70.00 Turkey HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 Hongkong POS-LT Lithium mining investment — — — — 100.00 100.00 Australia POSCO SINGAPORE LNG TRADING PTE. LTD. LNG trading — — — 50.00 50.00 100.00 Singapore ZHEJIANG POSCO-HUAYOU Anode material manufacturing — — — 100.00 — 100.00 China POSCO Argentina S.A.U. Mineral exploration/manufacturing/sales — — — 100.00 — 100.00 Argentina POSCO RUS LLC Trading and business development 90.00 10.00 100.00 — — — Russia POSCO-CDSFC Steel structure manufacturing 50.20 49.80 100.00 — — — China POSCO MESDC S.A. DE C.V. Logistics & Steel sales — 56.80 56.80 — — — Mexico KIS Devonian Canada Corporation Petroleum gas extraction — 100.00 100.00 — — — Canada POSCO E&C VENEZUELA C.A. Civil engineering and construction — 100.00 100.00 — — — Venezuela PT PEN INDONESIA Construction — 100.00 100.00 — — — Indonesia POSCO Engineering and Construction — UZ Civil engineering and construction — 100.00 100.00 — — — Uzbekistan (*1) Reclassified to associate from subsidiary during the year ended December 31, 2018. The equity of controlling company increased by ￦ ￦ Cash dividends paid to POSCO by subsidiaries in 2016, 2017 and 2018 amounted to ￦ ￦ ￦ As of December 31, 2018, there are no restrictions on the ability of subsidiaries to transfer funds to the controlling company, such as in the form of cash dividends, repayment of loans or payment of advances. (c) Details of non-controlling 1) December 31, 2016 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 4,038,313 460,376 397,370 5,163,436 713,039 9,696,140 20,468,674 Non-current 4,510,085 3,304,292 243,401 1,710,398 3,038,665 7,749,277 20,556,118 Current liabilities (3,662,811 ) (1,120,077 ) (109,016 ) (3,284,090 ) (937,668 ) (9,669,053 ) (18,782,715 ) Non-current (1,681,182 ) (2,337,612 ) (2,337 ) (855,791 ) (2,172,226 ) (2,856,498 ) (9,905,646 ) Equity 3,204,405 306,979 529,418 2,733,953 641,810 4,919,866 12,336,431 Non-controlling 1,271,750 92,094 211,767 1,290,450 514,200 945,962 4,326,223 Sales 15,417,550 1,244,711 1,076,455 5,352,395 1,657,890 23,251,563 48,000,564 Profit (loss) for the period 113,832 (187,151 ) 41,829 (760,187 ) (130,809 ) (461,034 ) (1,383,520 ) Profit (loss) attributable to non-controlling 45,177 (56,145 ) 16,732 (358,815 ) (14,357 ) (312,297 ) (679,705 ) Cash flows from operating activities 337,338 45,672 30,295 (211,182 ) 18,107 53,050 273,280 Cash flows from investing activities (35,054 ) (8,804 ) (42,021 ) (102,939 ) (1,047 ) (253,206 ) (443,071 ) Cash flows from financing activities (before dividends to non-controlling (295,226 ) (36,286 ) (1,250 ) (20,953 ) (2,875 ) 204,797 (151,793 ) Dividend to non-controlling (22,597 ) — (4,726 ) (14,800 ) (24,378 ) (7,349 ) (73,850 ) Effect of exchange rate fluctuation on cash held 10 67 1 760 — 1,687 2,525 Net increase (decrease) in cash and cash equivalents (15,529 ) 649 (17,701 ) (349,114 ) (10,193 ) (1,021 ) (392,909 ) 2) December 31, 2017 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 4,483,544 557,041 441,325 4,878,251 1,054,538 8,579,813 19,994,512 Non-current 4,590,394 2,771,504 316,724 2,444,616 2,859,824 6,676,559 19,659,621 Current liabilities (4,221,443 ) (1,237,255 ) (145,649 ) (3,896,680 ) (785,462 ) (8,313,902 ) (18,600,391 ) Non-current (1,549,013 ) (1,933,247 ) (970 ) (833,403 ) (2,200,065 ) (2,048,454 ) (8,565,152 ) Equity 3,303,482 158,043 611,430 2,592,784 928,835 4,894,016 12,488,590 Non-controlling 1,224,303 47,413 244,572 1,223,816 762,390 974,941 4,477,435 Sales 20,891,526 1,635,837 1,163,918 5,794,532 1,578,026 23,547,072 54,610,911 Profit (loss) for the period 115,321 (117,729 ) 101,019 169,011 70,795 258,053 596,470 Profit (loss) attributable to non-controlling 42,739 (35,318 ) 40,408 79,775 7,770 39,605 174,979 Cash flows from operating activities 128,875 (27,817 ) 20,042 (84,840 ) 30,295 140,418 206,973 Cash flows from investing activities (86,365 ) (5,502 ) (18,699 ) (171,924 ) (2,792 ) (63,621 ) (348,903 ) Cash flows from financing activities (before dividends to non-controlling (19,295 ) 31,782 8 150,801 220,317 (38,090 ) 345,523 Dividend to non-controlling (22,597 ) — (7,088 ) — (24,183 ) (12,777 ) (66,645 ) Effect of exchange rate fluctuation on cash held (459 ) (147 ) (6 ) (3,541 ) — (15,532 ) (19,685 ) Net increase (decrease) in cash and cash equivalents 159 (1,684 ) (5,743 ) (109,504 ) 223,637 10,398 117,263 3) December 31, 2018 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 5,311,596 615,491 416,284 4,100,967 825,241 9,137,798 20,407,377 Non-current 4,363,490 2,730,865 460,905 1,911,844 2,767,203 5,493,324 17,727,631 Current liabilities (4,724,056 ) (1,368,498 ) (140,268 ) (3,007,029 ) (1,197,845 ) (8,026,474 ) (18,464,170 ) Non-current (1,563,107 ) (1,754,797 ) (10,767 ) (608,089 ) (1,445,288 ) (1,925,084 ) (7,307,132 ) Equity 3,387,923 223,061 726,154 2,397,693 949,311 4,679,564 12,363,706 Non-controlling 1,255,728 66,918 290,461 1,131,733 335,203 929,506 4,009,549 Sales 23,314,595 1,871,634 1,340,984 6,799,292 1,841,187 24,721,939 59,889,631 Profit (loss) for the period 113,196 54,257 142,918 290,131 (73,948 ) (56,151 ) 470,403 Profit (loss) attributable to non-controlling 41,956 16,277 57,167 136,944 (8,116 ) (101,156 ) 143,072 Cash flows from operating activities (61,173 ) 89,131 29,865 207,729 16,211 14,869 296,632 Cash flows from investing activities (12,780 ) (6,432 ) (15,801 ) 272,230 35,460 (13,199 ) 259,478 Cash flows from financing activities (before dividends to non-controlling 99,496 (82,295 ) — (400,499 ) (71,378 ) (16,094 ) (470,770 ) Dividend to non-controlling (22,862 ) — (8,270 ) — (19,813 ) (6,906 ) (57,851 ) Effect of exchange rate fluctuation on cash held 807 21 (17 ) 1,257 — 1,682 3,750 Net increase (decrease) in cash and cash equivalents 3,488 425 5,777 80,717 (39,520 ) (19,648 ) 31,239 (d) Details of associates and joint ventures 1) Associates Details of associates as of December 31, 2017 and 2018 are as follows: Ownership (%) Investee Category of business 2017 2018 Region [Domestic] New Songdo International City Development, LLC Real estate rental 29.90 29.90 Seoul Gale International Korea, LLC Real estate rental 29.90 29.90 Seoul SNNC Raw material manufacturing and sales 49.00 49.00 Gwangyang KONES, Corp. Technical service 41.67 41.67 Gyeongju CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd Real estate development 29.53 29.53 Chungju DAEHO GLOBAL MANAGEMENT CO., LTD. Investment advisory service 35.82 35.82 Pohang Mokpo Deayang Industrial Corporation Real estate development and rental 27.40 27.40 Mokpo Gunggi Green Energy (*1) Electricity generation 19.00 19.00 Hwaseong Pohang Special Welding Co., Ltd. Welding material and tools manufacturing and sales 50.00 50.00 Pohang KoFC POSCO HANWHA KB Shared Growth NO. 2. Private Equity Fund (*1) Investment in new technologies 12.50 12.50 Seoul EQP POSCO Global NO1 Natural Resources Private Equity Fund Investment in new technologies 31.14 31.27 Seoul KC Chemicals CORP. (*1) Machinery manufacturing 19.00 19.00 Hwaseong Garolim Tidal Power Plant Co., Ltd Tidal power plant construction and management 32.13 32.13 Seosan POSTECH Social Enterprise Fund (*1) Investment in new technologies 9.17 9.17 Seoul QSONE Co., Ltd. Real estate rental and facility management 50.00 50.00 Seoul Chun-cheon Energy Co., Ltd Electricity generation 45.67 45.67 Chuncheon Keystone NO. 1 Private Equity Fund Private equity financial 40.45 40.45 Seoul Noeul Green Energy (*1) Electricity generation 10.00 10.00 Seoul Posco-IDV (*1) Investment in new technologies 17.86 17.86 Seoul Daesung Steel (*1) Steel sales 17.54 17.54 Busan Pohang E&E Co., LTD Investment in waste energy 30.00 30.00 Pohang POSCO Energy Valley Fund Investment in new technologies 20.00 20.00 Pohang 2016 PoscoPlutus New technology Fund Investment in new technologies 25.17 25.17 Seoul Hyundai Invest Guggenheim CLO Qualified Private Special Asset Trust No.2 Investment in new technologies 38.47 38.47 Seoul PoscoPlutus Bio Fund (*1) Investment in new technologies 11.97 11.97 Seoul PoscoPlutus Project Fund (*1) Investment in new technologies 11.91 11.91 Seoul Posco Agri-Food Export Fund Investment in new technologies 30.00 30.00 Seoul PoscoPlutus Project 2nd Project Fund (*1) Investment in new technologies 0.61 0.61 Seoul Posco Culture Contents Fund Investment in new technologies 31.67 31.67 Seoul PCC_Centroid 1st Fund Investment in new technologies 24.10 24.10 Seoul PCC Amberstone Private Equity Fund 1 (*1) Investment in new technologies 9.71 8.80 Seoul UITrans LRT Co., Ltd. Transporting 38.19 38.19 Seoul POSCO Advanced Technical Staff Fund (*1) Investment in new technologies 15.87 15.87 Seoul POSCO 4th Industrial Revolution Fund (*1) Investment in new technologies 20.00 19.05 Seoul Clean Gimpo Co., Ltd. Construction 29.58 29.58 Gimpo Incheon-Gimpo Expressway Co., Ltd. (*1) Construction 18.26 18.26 Anyang Pureun Tongyeong Enviro Co., Ltd. Sewerage treatment 20.40 20.40 Tongyeong Pure Gimpo Co., Ltd. Construction 28.79 28.79 Seoul POSCO PLANTEC Co., Ltd. (*2) Construction of industrial plant 73.94 73.94 Ulsan Postech Early Stage Fund (*1) Investment in new technologies 10.00 10.00 Pohang Posgreen Co., Ltd. (*1) Lime and plaster manufacturing 19.00 19.00 Gwangyang Clean Iksan Co., Ltd. Construction 23.50 23.50 Iksan Innovalley Co., Ltd. Real estate development 28.77 28.77 Yongin Applied Science Corp. Machinery manufacturing 23.87 22.89 Paju Pohang Techno Valley PFV Corporation (*3) Real estate development, supply and rental 57.39 57.39 Pohang BLUE OCEAN Private Equity Fund Private equity financial 27.52 27.52 Seoul Western Inland highway CO., LTD. (*4) Construction — 27.50 Incheon Metropolitan Outer Ring Expressway co., ltd. (*4) Investment in Expressway — 47.58 Incheon IT ENGINEERING CO., LTD. (*1,4) Vehicle engineering — 10.84 Seoul PCC Bio 1ST Fund (*1,4) Investment in new technologies — 13.46 Seoul INNOPOLIS Job Creation Fund II (*1,4) Investment in new technologies — 6.43 Seoul POSPower Co., Ltd. (*5) Generation of electricity — 34.00 Samcheok INKOTECH, INC. (*1,4) Electricity generation and sales — 10.00 Seoul PCC Social Enterprise Fund II (*1,4) Investment in venture companies — 16.67 Seoul PCC Amberstone Private Equity Fund II (*1,4) Private equity trust — 19.70 Seoul Synapse Fund (*1,4) Investment in new technologies — 16.26 Seoul NEXTRAIN Co., Ltd (*4) Service maintenance and management — 32.00 Incheon TK CHEMICAL CORPORATION (*1,4) Chemical — 8.80 Daegu Hanil-Daewoo Cement Co., Ltd. (*1,4) Cement — 15.00 Incheon Pohang Techno Valley AMC (*6) Construction 29.50 — Pohang [Foreign] VSC POSCO Steel Corporation Steel processing and sales 50.00 50.00 Vietnam POSCHROME (PROPRIETARY) LIMITED Raw material manufacturing and sales 50.00 50.00 South CAML RESOURCES PTY LTD Raw material manufacturing and sales 33.34 33.34 Australia Nickel Mining Company SAS Raw material manufacturing and sales 49.00 49.00 New PT. Wampu Electric Power Construction and civil engineering 20.00 20.00 Indonesia POSK (Pinghu) Steel Processing Center Co., Ltd. Steel processing and sales 20.00 20.00 China PT.INDONESIA POS CHEMTECH CHOSUN Ref Refractory manufacturing and sales 30.19 30.19 Indonesia NS-Thainox Steel manufacturing and sales 49.00 49.00 Vietnam Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd Tinplate manufacturing and sales 34.00 34.00 China PT. Tanggamus Electric Power (*1) Construction and civil engineering 17.50 17.50 Indonesia LLP POSUK Titanium Titanium manufacturing and sales 36.83 36.83 Kazakhstan LI3 ENERGY INC Resource development 26.06 26.06 Peru IMFA ALLOYS FINLEASE LTD Raw material manufacturing and sales 24.00 24.00 India KRAKATAU POS-CHEM DONG-SUH (*1) Chemical by-product manufacturing and sales 19.00 19.00 Indonesia 7623704 Canada Inc. (*1) Investments management 10.40 10.40 Canada Hamparan Mulya Resource development 45.00 45.00 Indonesia POS-SEAH Steel manufacturing and sales 25.00 25.00 China Eureka Moly LLC Raw material manufacturing and sales 20.00 20.00 USA PT. Batutua Tembaga Raya Raw material manufacturing and sales 22.00 22.00 Indonesia KIRIN VIETNAM CO., LTD (*1) Panel manufacturing 19.00 19.00 Vietnam POSCO SeAH Steel Wire (Nantong) Co., Ltd. Steel processing and sales 25.00 25.00 China POS-SeAH Steel manufacturing and sales 25.00 25.00 Thailand Jupiter Mines Limited (*1) Resource development 17.06 6.93 Australia SAMHWAN VINA CO., LTD (*1) Steel manufacturing and sales 19.00 19.00 Vietnam JB CLARK HILLS Construction 25.00 25.00 Philippines Saudi-Korean Company for Maintenance Properties Management LLC (*1) Building management 19.00 19.00 Saudi Sebang Steel Scrap sales 49.00 49.00 Japan NCR LLC Coal sales 29.41 29.41 Canada AMCI (WA) PTY LTD Iron ore sales & mine development 49.00 49.00 Australia SHANGHAI LANSHENG DAEWOO CORP. Trading 49.00 49.00 China SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. Trading 49.00 49.00 China General Medicines Company Ltd. Medicine manufacturing and sales 33.00 33.00 Sudan KOREA LNG LTD. Gas production and sales 20.00 20.00 England AES-VCM Electricity generation 30.00 30.00 Vietnam KG Power(M) SDN. BHD Resource development 20.00 20.00 Malaysia South-East Asia Gas Pipeline Company Ltd. Pipeline construction and management 25.04 25.04 Myanmar GLOBAL KOMSCO Daewoo LLC Cotton celluloid manufacturing and sales 35.00 35.00 Uzbekistan POSCO-Poggenamp Electrical Steel Pvt. Ltd. Steel processing and sales 26.00 26.00 India Qingdao Pohang DGENX Stainless SteelPipeCo., Ltd (*4) Exhaust meter manufacturing — 40.00 China SHINPOONG DAEWOO PHARMA VIETNAM CO., LTD (*1,4) Medicine production — 3.42 Vietnam ERAE Automotive Systems Mexico, S. DE R.L. DE C.V (*1,4) Automobile parts manufacturing — 7.65 Mexico (*1) Considering the composition of board of directors, the Company is able

Statement of Compliance

Statement of Compliance	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Statement of Compliance	2. Statement of Compliance The consolidated financial statements have been prepared in accordance with International Financial Reporting Standards (“IFRSs”), as issued by the International Accounting Standards Board. The consolidated financial statements were authorized for issue by the authorized directors on March 7, 2019. In 2018, the Company adopted IFRS No. 15 “Revenue from Contracts with Customers” and IFRS No. 9 “Financial Instruments” for the first time. Changes to significant accounting policies are described in Note 2 “Changes in Accounting Policies”. Basis of measurement The consolidated financial statements have been prepared on the historical cost basis, except for the following material items in the statement of financial position, as described in the accounting policy below. (a) Derivatives instruments measured at fair value (b) Financial instruments measured at fair value through profit or loss (c) Financial instruments measured at fair value through other comprehensive income (d) Financial instruments at fair value through profit or loss (e) Available-for-sale (f) Defined benefit liabilities measured at the present value of the defined benefit obligation less the fair value of the plan assets Functional and presentation currency The financial statements of POSCO and subsidiaries are prepared in functional currency of the respective operation. These consolidated financial statements are presented in Korean Won, which is POSCO’s functional currency which is the currency of the primary economic environment in which POSCO operates. Use of estimates and judgments The preparation of the consolidated financial statements in conformity with IFRS requires management to make judgments, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets, liabilities, income and expenses. Actual results may differ from these estimates. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period prospectively. (a) Judgments Information about critical judgments in applying accounting policies that have the most significant effect on the amounts recognized in the consolidated financial statements is included in the following notes: • Note 1 — Subsidiaries, associates and joint ventures • Note 11 — Investments in associates and joint ventures • Note 12 — Joint operations • Note 25 — Hybrid bonds (b) Assumptions and estimation uncertainties Information about assumptions and estimation uncertainties that have a significant risk of resulting in a material adjustment within the next fiscal year is included in the following notes: • Note 11 — Investments in associates and joint ventures • Note 14 — Property, plant and equipment, net • Note 15 — Goodwill and other intangible assets, net • Note 20 — Provisions • Note 21 — Employee benefits • Note 23 — Financial instruments • Note 29 — Revenue — contract balances • Note 35 — Income taxes • Note 38 — Commitments and contingencies (c) Measurement of fair value The Company’s accounting policies and disclosures require the measurement of fair values, for both financial and non-financial The valuation team regularly reviews significant unobservable inputs and valuation adjustments. If third party information, such as broker quotes or pricing services, is used to measure fair values, then the valuation team assesses the evidence obtained from the third parties to support the conclusion that such valuations meet the requirements of IFRS including the level in the fair value hierarchy in which such valuation techniques should be classified. Significant valuation issues are reported to the Company’s Audit Committee. When measuring the fair value of an asset or a liability, the Company uses market observable data as far as possible. Fair values are categorized into different levels in a fair value hierarchy based on the inputs used in the valuation techniques as follows. • Level 1 — unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2 — inputs other than quoted prices included in Level 1 that are observable for the assets or liability, either directly or indirectly. • Level 3 — inputs for the assets or liability that are not based on observable market data. If the inputs used to measure the fair value of an asset or a liability might be categorized in different levels of the fair value hierarchy, then the fair value measurement is categorized in its entirety in the same level of the fair value hierarchy as the lowest level input that is significant to the entire measurement. The Company recognizes transfers between levels of the fair value hierarchy at the end of the reporting period during which the change has occurred. Information about the assumptions made in measuring fair values is included in the following note: • Note 23 — Financial instruments Changes in Accounting Policies The Company has initially adopted IFRS No. 15 “Revenue from Contracts with Customers” and IFRS No. 9 “Financial Instruments” from January 1, 2018. The other accounting standards adopted from January 1, 2018 had no significant effect on the Company’s consolidated financial statements. The effect of initially applying IFRS No. 15 and IFRS No. 9 is mainly attributable to the following: • identify the shipping services included in certain sales contracts as a separate performance obligation • determine separate construction contracts such as design, purchase and construction services which are highly dependent or correlated as a single performance obligation • estimate variable consideration such as sales discount and price adjustments based on performance • change in the method of revenue recognition from service contracts without enforceable right to payment for performance completed • change in percentage of completion due to excessive use of materials • recognize as an expense immediately of prepaid contract cost unless those costs are explicitly chargeable to the customers regardless of whether the contract is obtained • change in classification and subsequent measurement of financial assets • change in timing of recognition of impairment loss on financial assets (a) IFRS No. 15 “Revenue from Contracts with Customers” IFRS No. 15 “Revenue from Contracts with Customers” provides a unified five-step model for determining the timing, measurement and recognition of revenue. It replaced previous revenue recognition guidance, including IAS No. 18 “Revenue”, IAS No. 11 “Construction Contracts”, SIC No. 31 “Revenue- Barter Transactions Involving Advertising Services”, IFRIC No. 13 “Customer Loyalty Programs”, IFRIC No. 15 “Agreements for the Construction of Real Estate”, and IFRIC No. 18 “Transfers of Assets from Customers”. The Company applied the modified retrospective approach by recognizing the cumulative impact of initially applying the revenue standard as of January 1, 2018, the date of initial application, and the Company also decided to apply the practical expedients as allowed by IFRS No. 15 by applying the new standard only to those contracts that are not considered as completed contracts at the date of initial application. Accordingly, the Company did not restate the financial statements for comparative periods. The following table summarizes the impact, net of tax, of transition to IFRS No. 15 on retained earnings and non-controlling Retained earnings Non-controlling interests (in millions of Won) Shipping services included in the sales contract ￦ (949 ) (156 ) Separate construction contract determined to be a single performance obligation 452 628 Variable consideration for sales discounts and price adjustments based on performance (2,613 ) 172 Change in revenue recognition method for contracts without enforceable right to payment (1,189 ) (1,115 ) Change in percentage of completion due to excessive use of materials (2,855 ) (1,512 ) Recognize prepaid contract cost as an expense (63,753 ) (56,993 ) ￦ (70,907 ) (58,976 ) The details of new significant accounting policies and impacts of the adoption of IFRS No. 15 are as follows: 1) Identification of performance obligations The Company holds certain contracts for sales of manufactured product and merchandise which include transport service. When applying IFRS No. 15, sales of manufactured products or merchandise and delivery of products (i.e. shipping service) are identified as separate performance obligations in the contracts with customers. For transactions for which the shipping terms are on shipment basis and the customer pays shipping costs, the two performance obligations are separately accounted for because delivery of products is performed after the control over the products is transferred to the customer. The transaction price allocated to the performance obligation of delivery service is recognized when the obligation of delivery of the product is completed. The Company identified shipping service included in the sales contract as a separate performance obligation that will be satisfied over the promised service period. This change in relevant accounting policy resulted in decreases in revenue and cost of sales, increases in other current assets and contract liabilities and decrease in other payables as of and for the year ended December 31, 2018. In addition, the Company presented costs incurred in the shipping services in cost of sales from January 1, 2018, which were previously presented in selling and administrative expenses. Certain construction contracts of the Company include design, purchase and construction services through separate service contracts. According to IFRS No. 15, if service or goods provided by the Company are highly dependent or correlated, the Company should identify them as a single performance obligation regardless of the number of contracts made. The Company considered these service contracts as a combined single obligation and identified as a single performance obligation. This change in accounting policy resulted in decreases in revenue and contract assets as of and for the year ended December 31, 2018. 2) Variable consideration Under IFRS No. 15, the Company estimates the amount of variable consideration by using the expected value which the Company expects to better predict the amount of consideration. The Company recognizes revenue with transaction price including variable consideration only to the extent that it is highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the refund period has lapsed. In certain sales arrangements, unit price is subject to adjustment due to quality issues of products. A certain percentage of sales discount is also provided in case customers make payment before the settlement due date. In addition, certain service contracts are subject to compensation payment if the Company fails to achieve a promised level of obligation. The Company changed its accounting treatment regarding variable consideration in accordance with IFRS No. 15. This change in relevant accounting policy resulted in decrease in revenue and increase in contract liabilities as of and for the year ended December 31, 2018. 3) Performance obligation satisfied over time In accordance with IFRS No. 15, revenue is recognized over time by measuring progress only if the Company’s performance does not create an asset with an alternative use to the Company and the Company has an enforceable right to payment for performance completed to date. The Company has determined that it has no enforceable right to payment for performance completed to date for certain service contracts. This change in relevant accounting policy resulted in increases in revenue and cost of sales and increases in inventories, contract assets and contract liabilities as of and for the year ended December 31, 2018. According to IFRS No. 15, the effects of any inputs that do not depict the transfer of control of goods or services to the customer such as the costs of wasted materials, labor or other resources to fulfill the contract that were not reflected in the price of the contract should be excluded from calculating percentage of completion. This change in relevant accounting policy resulted in increase in revenue and decreases in contract assets and liabilities as of and for the year ended December 31, 2018. 4) Incremental costs of obtaining a contract In accordance with IFRS No. 15, the Company recognizes as an asset the incremental costs of obtaining a contract with a customer if the Company expects to recover those costs, and costs that are recognized as assets are amortized over the period that the related goods or services are transferred to the customer. Certain costs incurred in construction segment such as costs to obtain a contract that would have been incurred regardless of whether the contract was obtained is recognized as an expense immediately, unless those costs are explicitly chargeable to the customer regardless of whether the contract is obtained. Such costs have been previously capitalized if it is probable the related contracts will be entered into. This change in relevant accounting policy resulted in decrease in cost of sales, increases in revenue, selling and administrative expenses and finance costs, decreases in contract assets, other current assets and contract liabilities and increase in provisions as of and for the year ended December 31, 2018. 5) Impact of changes in accounting policies The effects of adoption of IFRS No. 15 to the Company’s consolidated statements of financial position and consolidated statements of comprehensive income as of and for the year ended December 31, 2018 are as follows. There is no material impact on the Company’s consolidated statement of cash flows for the year ended December 31, 2018. As reported Adjustments of IFRS No. 15 Amounts without IFRS No. 15 (in millions of Won) Consolidated financial statements of financial position Current assets ￦ 34,151,972 193,400 34,345,372 Trade accounts and notes receivable 9,130,204 86,293 9,216,497 Inventories 12,153,303 6,584 12,159,887 Other current assets 684,464 100,523 784,987 Non-current 44,625,019 (41,589 ) 44,583,430 Deferred tax assets 1,408,787 (41,589 ) 1,367,198 Current liabilities 19,430,577 21,605 19,452,182 Others payables 1,720,097 17,809 1,737,906 Current income tax liabilities 948,166 (640 ) 947,526 Provisions 298,453 (28,748 ) 269,705 Other current liabilities 2,090,307 33,184 2,123,491 Retained earnings 44,160,659 68,182 44,228,841 Non-controlling 3,347,257 62,024 3,409,281 Consolidated statements of comprehensive income Revenue ￦ 65,154,636 135 65,154,771 Cost of sales (57,129,060 ) 1,206,973 (55,922,087 ) Selling and administrative expenses (2,429,781 ) (1,204,764 ) (3,634,545 ) Finance costs (2,244,416 ) 178 (2,244,238 ) Profit before income taxes 3,616,016 2,522 3,618,538 Income tax expense (1,683,630 ) (2,198 ) (1,685,828 ) Profit 1,932,386 324 1,932,710 (b) IFRS No. 9 “Financial Instruments” IFRS No. 9 “Financial Instruments” regulates requirements for measurement and recognition of certain contracts in relation to trading financial assets and liabilities or nonfinancial items. It replaced existing guidance in IAS No. 39 “Financial Instruments: Recognition and Measurement”. The Company applied retrospectively the standard with exemptions where an entity is not required to restate the comparative information for prior periods in relation to classification and measurement (including impairment) changes. The Company recognized the cumulative effect resulting from initial application of IFRS No. 9 as reserves, retained earnings and non-controlling The following table summarizes the impact, net of tax, of transition to IFRS No. 9 on reserves, retained earnings and non-controlling Reserves Retained Non-controlling interests (in millions of Won) Classification to fair value through profit or loss in securities and select to fair value through other comprehensive income in equity securities (*1) ￦ (498,517 ) 498,517 — Recognition of expected credit losses — (51,450 ) (34,754 ) ￦ (498,517 ) 447,067 (34,754 ) (*1) Includes a decrease in reserve (capital adjustment arising from investments in equity-accounted investees) of ￦ ￦ The details of new significant accounting policies and the nature and effect of the changes to previous accounting policies are set out below. 1) Classification and measurement of financial assets and financial liabilities IFRS No. 9 contains three principal classification categories for financial assets: measured at amortized cost, at fair value through other comprehensive income and at fair value through profit or loss. The classification of financial assets under IFRS No. 9 is generally based on the business model in which a financial asset is managed and its contractual cash flow characteristics. Under IFRS No. 9, derivatives embedded in contracts where the host is a financial asset in the scope of the standard are never separated. Instead, the hybrid financial instrument as a whole is assessed for classification. As of January 1, 2018, the date of initial application, measurement categories and carrying amounts of financial assets in accordance with IAS No. 39 “Financial Instruments: Recognition and Measurement” and IFRS No. 9 “Financial Instruments” are as follows: Original classification under IAS No. 39 Original amounts IAS No. 39 New classification under IFRS No. 9 New carrying amounts IFRS No. 9 (in millions of Won) Derivative assets Financial assets at fair value through ￦ 65,051 Fair value through ￦ 65,051 Hedging instrument 3,239 Hedging instrument 3,239 Cash and cash equivalents Loans and receivables 2,612,530 Amortized cost 2,612,530 Trade accounts and notes receivable (*1) Loans and receivables 8,901,867 Amortized cost 8,799,161 Other receivables (*1) Loans and receivables 2,195,466 Fair value through 1,898 Amortized cost 2,188,820 Equity securities (*2) Available-for-sale 1,421,295 Fair value through 17,812 Fair value through 1,403,483 Debt securities (*2) Available-for-sale 190,579 Fair value through 188,276 Held-to-maturity Fair value through 2,303 5,211 Amortized cost 5,211 Other Securities (*2) Available-for-sale 366,241 Fair value through 366,241 Deposit instruments Loans and receivables 1,358,311 Amortized cost 1,358,311 Short-term financial instruments Financial assets at 1,970 Fair value through 5,547,637 Loans and receivables 5,545,667 (*1) As a result of the adoption of IFRS No. 9, as of January 1, 2018, the date of initial application, loss allowance was increased by ￦ non-controlling ￦ ￦ (*2) As a result of the adoption of IFRS No. 9, as of January 1, 2018, the date of initial application, with respect to securities classified as fair value through profit or loss and equity securities determined fair value through other comprehensive income, reserves were decreased by ￦ ￦ IFRS No. 9 “Financial Instruments” retains most of the requirements of IAS No. 39 “Financial Instruments: Recognition and Measurement” for the classification and measurement of financial liabilities. Accordingly, the application of IFRS No. 9 “Financial Instruments” has no significant effect on the Company’s accounting policies related to financial liabilities. 2) Impairment of financial assets IFRS No. 9 replaces the incurred loss model in IAS No. 39 with a forward-looking expected credit loss model for debt instruments, lease receivables, contractual assets, loan commitments, and financial guarantee contracts. Under IFRS No. 9, impairment losses are likely to be recognized earlier than using the incurred loss model under the existing guidance in IAS No. 39 as loss allowances is measured either 12-month As of January 1, 2018, the date of initial application, the Company recognized an increase in loss allowances of ￦ non-controlling ￦ ￦ In addition to the application of IFRS No. 9, the Company applied the amendments to IAS No. 1 “Presentation of Financial Statements”, which requires the recognition of impairment of financial assets to be separated in the consolidated statements of comprehensive income. Impairment loss on trade accounts and notes receivable and Impairment loss on other receivables are presented as separate items. 3) Hedge Accounting Regarding the initial application of IFRS No. 9, the Company determined to consistently apply hedge accounting requirements of IAS No. 39.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies The significant accounting policies applied by the Company in preparation of its consolidated financial statements are included below. The accounting policies set out below have been applied consistently to all periods presented in these consolidated financial statements, except for those as disclosed in note 2. Basis of consolidation (a) Business combinations The Company accounts for business combinations using the acquisition method when control is transferred to the Company. The consideration transferred in the acquisition is generally measured at fair value, as are the identifiable net assets acquired. Any goodwill that arises is tested annually for impairment. Any gain on bargain purchase is recognized in profit or loss immediately. Transaction costs are expensed as incurred, except if related to the issue of debt or equity securities. The consideration transferred does not include amounts related to the settlement of pre-existing Any contingent consideration payable is measured at fair value at the acquisition date. If the contingent consideration is classified as equity, then it is not remeasured and settlement is accounted for within equity. Otherwise, subsequent changes in the fair value of the contingent consideration are recognized in profit or loss. If share-based payment awards (replacement awards) are required to be exchanged for awards held by the acquiree’s employees (acquiree’s awards), then all or a portion of the amount of the acquirer’s replacement awards is included in measuring the consideration transferred in the business combination. This determination is based on the market-based measure of the replacement awards compared with the market-based measure of the acquiree’s awards and the extent to which the replacement awards relate to pre-combination (b) Non-controlling Non-controlling (c) Subsidiaries Subsidiaries are entities controlled by the Company. The Company controls an entity when it is exposed to, or has rights to, variable returns from its involvement with the entity and has the ability to affect those returns through its power over the entity. The financial statements of subsidiaries are included in the consolidated financial statements from the date on which control commences until the date on which control ceases. (d) Loss of control When the Company loses control over a subsidiary, it derecognizes the assets and liabilities of the subsidiary, and any related non-controlling (e) Interests in equity-accounted investees The Company’s interests in equity-control investees comprise interests in associates and joint ventures. Associates are those entities in which the Company has significant influence, but not control or joint control, over the financial and operating policies. A joint venture is an arrangement in which the Company has joint control, whereby the Company has rights to the net assets of the arrangement, rather than rights to its assets and obligations for its liabilities. Interests in associates and joint ventures are accounted for using the equity method. They are recognized initially at cost, which includes transaction costs. Subsequent to initial recognition, the consolidated financial statements include the Company’s share of the profit or loss and other comprehensive income of equity-accounted investees, until the date on which significant influence or joint control ceases. (f) Transactions eliminated on consolidation Intra-group balances and transactions, and any unrealized income and expenses arising from intra-group transactions, are eliminated. Unrealized gains arising from transactions with equity-accounted investees are eliminated against the investment to the extent of the Company’s interest in the investee. Unrealized losses are eliminated in the same way as unrealized gains, but only to the extent that there is no evidence of impairment. Foreign currency transactions and translation (a) Foreign currency transactions Foreign currency transactions are initially recorded using the spot exchange rate between the functional currency and the foreign currency at the date of the transaction. At the end of each reporting period, foreign currency monetary items are translated using the closing rate. Non-monetary Non-monetary Exchange differences arising on the settlement of monetary items or on translating monetary items at rates different from those at which they were translated on initial recognition during the period or in previous financial statements are recognized in profit or loss in the period in which they arise. When gains or losses on non-monetary non-monetary (b) Foreign operations If the presentation currency of the Company is different from a foreign operation’s functional currency, the financial statements of the foreign operation are translated into the presentation currency using the following methods: The assets and liabilities of foreign operations, whose functional currency is not the currency of a hyperinflationary economy, are translated to presentation currency at exchange rates at the reporting date. The income and expenses of foreign operations are translated to functional currency at exchange rates at the dates of the transactions. Foreign currency differences are recognized in other comprehensive income. Any goodwill arising on the acquisition of a foreign operation and any fair value adjustments to the carrying amounts of assets and liabilities arising on the acquisition of that foreign operation are treated as assets and liabilities of the foreign operation. Thus, they are expressed in the functional currency of the foreign operation and translated at the closing rate. When a foreign operation is disposed of, the relevant amount in the translation is transferred to profit or loss as part of the profit or loss on disposal. On the partial disposal of a subsidiary that includes a foreign operation, the relevant proportion of such cumulative amount is reattributed to non-controlling Foreign exchange gains or losses arising from a monetary item receivable from or payable to a foreign operation, the settlement of which is neither planned nor likely to occur in the foreseeable future and which in substance is considered to form part of the net investment in the foreign operation, are recognized in other comprehensive income in the translation reserve. Cash and cash equivalents Cash and cash equivalents comprise cash on hand, demand deposits, and short-term investments in highly liquid securities that are readily convertible to known amounts of cash with maturities of three months or less from the acquisition date and which are subject to an insignificant risk of changes in value. Equity investments are excluded from cash and cash equivalents. Non-derivative Trade receivables and debt securities issued are initially recognized when they are originated. All other financial assets are initially recognized when the Company becomes a party to the contractual provisions of the instrument. A financial asset(unless it is a trade receivable without a significant financing component) is initially measured at fair value plus, for an item not at financial assets measured at fair value through profit or loss, transaction costs that are directly attributable to its acquisition or issue. A trade receivable without a significant financing component is initially measured at the transaction price. (a) Classification and subsequent measurement — Policies applicable from January 1, 2018 On initial recognition, a financial asset is classified as measured at amortized cost, debt instruments measured at fair value through other comprehensive income, equity instruments measured at fair value through other comprehensive income or financial assets measured at fair value through profit or loss. Financial assets are not reclassified subsequent to their initial recognition unless the Company changes its business model for managing financial assets, in which case all affected financial assets are reclassified on the first day of the first day of the first reporting period following the change in the business model. Financial assets measured at amortized cost A financial asset is measured at amortized cost if it meets both of the following conditions and is not designated as at fair value through profit or loss. • it is held within a business model whose objective is to hold assets to collect contractual cash flows, and • its contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. Financial assets measured at amortized cost are subsequently measured at amortized cost using the effective interest method. The amortized cost is reduced by impairment losses. Interest income, gains and losses on foreign currency translation and impairment losses are recognized in profit or loss. Any gain or loss on derecognition is recognized in profit or loss. Debt instruments measured at fair value through other comprehensive income A debt instrument is measured at fair value through other comprehensive income if it meets both of the following conditions and is not designated as at fair value through profit or loss. • it is held within a business model whose objective is achieved by both collection contractual cash flows and selling financial assets, and • its contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. Debt instruments measured at fair value through other comprehensive income are subsequently measured at fair value. Interest income which is calculated using the effective interest method, gains and losses from foreign currency translation and impairment losses are recognized in profit or loss and other net profit or loss is recognized in other comprehensive income. At the time of elimination, other accumulated comprehensive income is reclassified to profit or loss. Equity instruments measured at fair value through other comprehensive income On initial recognition of an equity investment that is not held for trading, the Company may irrevocably elect to present subsequent changes in the investment’s fair value in other comprehensive income. This election is made on an investment-by-investment Equity instruments measured at fair value through other comprehensive income are subsequently measured at fair value. Dividends are recognized as income in profit or loss unless the dividend clearly represents a recovery of part of the cost of the investment. Other net gains and losses are recognized in other comprehensive income and never reclassified to profit or loss. Financial assets measured at fair value through profit or loss All financial assets not classified as measured at amortized cost of fair value through other comprehensive income as described above are measured at fair value through profit or loss. This includes all derivative financial assets. On initial recognition, the Company may irrevocably designate a financial asset that otherwise meets the requirements to be measured at amortized cost or at fair value through other comprehensive income as at fair value through profit or loss if doing so eliminates or significantly reduces an accounting mismatch that would otherwise arise. Financial assets measured at fair value through profit or loss are subsequently measured at fair value. Net gains and losses, including any interest or dividend income, are recognized in profit or loss. (b) Classification and subsequent measurement — Policies applied before January 1, 2018 The Company recognizes and measures non-derivative financial assets by the following four categories: financial assets at fair value through profit or loss, held-to-maturity financial assets, loans and receivables and available-for-sale financial assets. Financial assets at fair value through profit or loss Financial assets are classified at fair value through profit or loss if they are held for trading or designated as such upon initial recognition. Upon initial recognition, transaction costs are recognized in profit or loss when incurred. Financial assets at fair value through profit or loss are measured at fair value, and changes therein are recognized in profit or loss. Held-to-maturity financial assets A non-derivative financial asset with a fixed or determinable payment and fixed maturity, for which the Company has the positive intention and ability to hold to maturity, is classified as held-to-maturity. Subsequent to initial recognition, held-to-maturity financial assets are measured at amortized cost using the effective interest rate method. Loans and receivables Loans and receivables are non-derivative financial assets with fixed or determinable payments that are not quoted in an active market. Subsequent to initial recognition, loans and receivables are measured at amortized cost using the effective interest method unless the effect of discounting is immaterial. Available-for-sale financial assets Available-for-sale financial assets are those non-derivative financial assets that are designated as available-for-sale or are not classified as financial assets at fair value through profit or loss, held-to-maturity financial assets or loans and receivables. Subsequent to initial recognition, they are measured at fair value, with changes in fair value, net of any tax effect, recorded in other comprehensive income in equity. Investments in equity instruments that do not have a quoted market price in an active market and whose fair value cannot be reliably measured and derivatives that are linked to and must be settled by delivery of such unquoted equity instruments are measured at cost. When a financial asset is derecognized or impairment losses are recognized, the cumulative gain or loss previously recognized in other comprehensive income is reclassified from equity to profit or loss. Dividends on an available-for-sale equity instrument are recognized in profit or loss when the Company’s right to receive payment is established. (c) Derecognition of non-derivative The Company derecognizes non-derivative If the Company retains substantially all the risks and rewards of ownership of the transferred financial assets, the Company continues to recognize the transferred financial assets and recognizes financial liabilities for the consideration received. (d) Offsetting a financial asset and a financial liability Financial assets and financial liabilities are offset and the net amount is presented in the consolidated statement of financial position only when the Company currently has a legally enforceable right to offset the recognized amounts, and there is the intention to settle on a net basis or to realize the asset and settle the liability simultaneously. Inventories Inventory costs, except materials-in-transit Inventories are measured at the lower of cost or net realizable value. The amount of any write-down The carrying amount of those inventories is recognized as cost of goods sold in the period in which the related revenue is recognized. Non-current Non-current non-current The Company recognizes an impairment loss for any initial or subsequent write-down of an asset or disposal group to fair value less costs to sell, and a gain for any subsequent increase in fair value less costs to sell, up to the cumulative impairment loss previously recognized in accordance with IAS No. 36 “Impairment of Assets”. A non-current Investment property Property held to earn rentals or for capital appreciation or both is classified as investment property. Investment property is measured initially at its cost. Transaction costs are included in the initial measurement. Subsequently, investment property is carried at depreciated cost less any accumulated impairment losses. Subsequent costs are recognized in the carrying amount of investment property at cost or, if appropriate, as separate items if it is probable that future economic benefits associated with the item will flow to the Company and the cost of the item can be measured reliably. The carrying amount of the replaced part is derecognized. The costs of the day-to-day Depreciation methods, useful lives and residual values are reviewed at the end of each reporting date and adjusted, if appropriate. The change is accounted for as a change in an accounting estimate. Property, plant and equipment Property, plant and equipment are initially measured at cost and after initial recognition, are carried at cost less accumulated depreciation and any accumulated impairment losses. The cost of property, plant and equipment includes expenditures arising directly from the construction or acquisition of the asset, any costs directly attributable to bringing the asset to the location and condition necessary for it to be capable of operating in the manner intended by management and, when the Company has an obligation to remove the asset or restore the site, an estimate of the costs of dismantling and removing the item and restoring the site on which it is located. The cost of replacing a part of an item is recognized in the carrying amount of the item of property, plant and equipment, if the following recognition criteria are met: (a) it is probable that future economic benefits associated with the item will flow to the Company, and (b) the cost can be measured reliably. The carrying amount of the replaced part is derecognized at the time the replacement part is recognized. The costs of the day-to-day Items of property, plant and equipment are depreciated from the date they are available for use or, in respect of self-constructed assets, from the date that the asset is completed and ready for use. Other than land, the costs of an asset less its estimated residual value are depreciated. Depreciation of property, plant and equipment is recognized in profit or loss on a straight-line basis, which most closely reflects the expected pattern of consumption of the future economic benefits embodied in the asset, over the estimated useful lives of each component of an item of property, plant and equipment. Land is not depreciated. Each part of an item of property, plant and equipment with a cost that is significant in relation to the total cost of the item is depreciated separately. The gain or loss arising from the derecognition of an item of property, plant and equipment is included in profit or loss when the item is derecognized. The estimated useful lives for the current and comparative periods are as follows: Buildings 5-50 Structures 4-50 Machinery and equipment 4-25 Vehicles 3-20 Tools 3-10 Furniture and fixtures 3-20 Lease assets 3-30 Bearer plants 20 years The estimated residual value, useful lives and the depreciation method are reviewed at least at the end of each reporting period and, if expectations differ from previous estimates, the changes are accounted for as changes in accounting estimates. Borrowing costs The Company capitalizes borrowing costs directly attributable to the acquisition, construction or production of a qualifying asset as part of the cost of that asset. Other borrowing costs are recognized in expense as incurred. A qualifying asset is an asset that requires a substantial period of time to get ready for its intended use or sale. Financial assets and inventories that are manufactured or otherwise produced over a short period of time are not qualifying assets. Assets that are ready for their intended use or sale when acquired are not qualifying assets. To the extent that the Company borrows funds specifically for the purpose of obtaining a qualifying asset, the Company determines the amount of borrowing costs eligible for capitalization as the actual borrowing costs incurred on that borrowing during the period less any investment income on the temporary investment of those borrowings. The Company immediately recognizes other borrowing costs as an expense. To the extent that the Company borrows funds generally and uses them for the purpose of obtaining a qualifying asset, the Company shall determine the amount of borrowing costs eligible for capitalization by applying a capitalization rate to the expenditures on that asset. The capitalization rate shall be the weighted average of the borrowing costs applicable to the borrowings of the Company that are outstanding during the period, other than borrowings made specifically for the purpose of obtaining a qualifying asset. The amount of borrowing costs that the Company capitalizes during a period shall not exceed the amount of borrowing costs incurred during that period. Intangible assets Intangible assets are measured initially at cost and, subsequently, are carried at cost less accumulated amortization and accumulated impairment losses. Amortization of intangible assets except for goodwill is calculated on a straight-line basis over the estimated useful lives of intangible assets from the date that they are available for use. The residual value of intangible assets is zero. However, as there are no foreseeable limits to the periods over which club memberships are expected to be available for use, this intangible asset is determined as having an indefinite useful life and not amortized. Intellectual property rights 4-25 Development expense 3-5 Port facilities usage rights 4-75 Other intangible assets 2-15 Amortization periods and the amortization methods for intangible assets with finite useful lives are reviewed at the end of each reporting period. The useful lives of intangible assets that are not being amortized are reviewed at the end of each reporting period to determine whether events and circumstances continue to support indefinite useful life assessments for those assets. Changes are accounted for as changes in accounting estimates. Expenditures on research activities, undertaken with the prospect of gaining new scientific or technical knowledge and understanding, are recognized in profit or loss as incurred. Development expenditures are capitalized only if development costs can be measured reliably, the product or process is technically and commercially feasible, future economic benefits are probable, and the Company intends to and has sufficient resources to complete development and to use or sell the asset. Other development expenditures are recognized in profit or loss as incurred. Subsequent expenditures are capitalized only when they increase the future economic benefits embodied in the specific asset to which they relate. All other expenditures, including expenditures on internally generated goodwill and brands, are recognized in profit or loss as incurred. Exploration for and evaluation of mineral resources POSCO is engaged in exploration projects for mineral resources through subsidiaries, associates and joint ventures or other contractual arrangements. Expenditures related to the development of mineral resources are recognized as exploration or development intangible assets. The nature of these intangible assets are as follows: (a) Exploration and evaluation assets Exploration and evaluation assets consist of expenditures for topographical studies, geophysical studies and trenching. These assets are reclassified as development assets when it is proved that the exploration has identified commercially viable mineral deposit. (b) Development assets When proved reserves are determined and development is sanctioned, development expenditures incurred are capitalized. These expenditures include evaluation of oil fields, construction of oil/gas wells, drilling for viability and others. On completion of development and inception of extraction for commercial production of developed proved reserves, the development assets are reclassified as either property, plant and equipment or as intellectual property rights (mining rights) under intangible assets based on the nature of the capitalized expenditure. The respective property, plant and equipment and intellectual property (mining rights) are each depreciated and amortized based on proved reserves on a unit of production basis. Government grants Government grants are not recognized unless there is reasonable assurance that the Company will comply with the grant’s conditions and that the grant will be received. (a) Grants related to assets Government grants whose primary condition is that the Company purchase, construct or otherwise acquire long-term assets are deducted from the carrying amount of the assets and recognized in profit or loss on a systematic and rational basis over the life of the depreciable assets. (b) Grants related to income Government grants which are intended to compensate the Company for expenses incurred are deducted from the related expenses. Leases The Company classifies and accounts for leases as either a finance or operating lease, depending on the terms. Leases where the Company assumes substantially all of the risks and rewards of ownership are classified as finance leases. All other leases are classified as operating leases. (a) Finance leases At the commencement of the lease term, the Company recognizes as finance assets and finance liabilities the lower amount of the fair value of the leased property and the present value of the minimum lease payments, each determined at the inception of the lease. Any initial direct costs are added to the amount recognized as an asset. Minimum lease payments are apportioned between the finance charge and the reduction of the outstanding liability. The finance charge is allocated to each period during the lease term so as to produce a constant periodic rate of interest on the remaining balance of the liability. Contingent rents are charged as expenses in the periods in which they are incurred. The depreciable amount of a leased asset is allocated to each accounting period during the period of expected use on a systematic basis consistent with the depreciation policy the Company adopts for similar depreciable assets that are owned. If there is no reasonable certainty that the Company will obtain ownership by the end of the lease term, the asset is fully depreciated over the shorter of the lease term and its useful life. (b) Operating leases Lease obligations under operating leases are recognized as an expense on a straight-line basis over the lease term. Contingent rents are charged as expenses in the periods in which they are incurred. (c) Determining whether an arrangement contains a lease Determining whether an arrangement is, or contains, a lease is based on the substance of the arrangement and requires an assessment of whether fulfillment of the arrangement is dependent on the use of a specific asset or assets (the asset) and the arrangement conveys a right to use the asset. At inception or reassessment of the arrangement, management of the Company separates payments and other consideration required by such an arrangement into those for the lease and those for other elements on the basis of their relative fair values. If management of the Company concludes for a financial lease that it is impracticable to separate the payments reliably, the Company recognizes an asset and a liability at an amount equal to the fair value of the underlying asset that was identified as the subject of the lease. Subsequently, the liability shall be reduced as payments are made and an imputed finance charge on the liability recognized using the purchaser’s incremental borrowing rate of interest. Impairment for financial assets — Policies applicable from January 1, 2018 The Company recognizes loss allowances for expected credit losses on: • financial assets measured at amortized cost • debt instruments measured at fair value through other comprehensive income • lease receivables, contractual assets, loan commitments, and financial guarantee contracts If credit risk has increased significantly since the initial recognition, a loss allowance for lifetime expected credit loss is required to be measured at the end of every reporting period. If credit risk has not increased significantly since the initial recognition, a loss allowance is measured based on 12-month If the financial instrument has low credit risk at the end of the reporting period, the Company may assume that the credit risk has not increased significantly since initial recognition. However, a loss allowance for lifetime expected credit losses is required for contract assets or trade receivables that do not contain a significant financing component. (a) Judgments on credit risk When determining whether the credit risk of a financial asset has increased significantly since initial recognition and when estimating expected credit losses, the Company considers reasonable and supportable information that is relevant and available without undue cost or effort. This includes both quantitative and qualitative information and analysis, based on the Company’s historical experience and informed credit assessment and including forward-looking information. The Company assumes that the credit risk on a financial asset has increased significantly if it is more than 30 days past due. The Company considers a financial asset to be in default when the borrower is unlikely to pay its credit obligations to the Company in full, without recourse by the Company to actions such as realizing security (if any is held). The Company considers a debt security to have low credit risk when its credit risk rating is equivalent to the globally understood definition of investment grade. (b) Measurement of expected credit losses Lifetime expected credit losses are the expected credit losses that result from all possible default events over the expected life of a financial instrument. 12-month Expected credit losses are a probability-weighted estimate of credit losses. Credit losses are measured as the present value of all cash shortfalls such as the difference between the cash flows due to the entity in accordance with the contract and the cash flows that the Company expects to receive. Expected credit losses for financial assets measured at amortized cost are recognized in profit or loss. Loss allowances for financial assets measured at amortized cost are deducted from carrying amount of the assets. For debt instruments measured at fair value through other comprehensive income, the loss allowance is charged to profit or loss and is recognized in other comprehensive income. (c) Credit-impaired financial assets At each reporting date, the Company assesses whether financial assets measured at amortized cost and debt instrument measured at fair value through other comprehensive income are credit-impaired. A financial asset is ‘credit-impaired’ when one or more events that have a detrimental impact on the estimated future cash flows of the financial asset have occurred. Objective evidence that a financial asset or group of financial assets are impaired includes: • significant financial difficulty of the issuer or borrower • a breach of contract, such as a default or delinquency in interest or principal payments • the lender, for economic or legal reasons relating to the borrower’s financial difficulty, granting to the borrower a concession that the lender would not otherwise consider • it becoming probable that the borrower will enter bankruptcy or other financial reorganization • the disappearance of an active market for that financial asset because of financial difficulties (d) Write-off The gross carrying amount of a financial asset is written off when the Company has no reasonable expectations of recovering a financial asset in entirety or a portion. The Company individually makes an assessment with respect to the timing and amount of write-off Impairment for financial assets — Policies applied before January 1, 2018 A financial asset not carried at fair value through profit or loss is assessed at each reporting date to determine whether there is objective evidence that it is impaired. A financial asset is impaired if objective evidence indicates that a loss event has occurred after the initial recognition of the asset, and that the loss event had a negative effect on the estimated future cash flows of that asset that can be estimated reliably. However, losses expected as a result of future events, regardless of likelihood, are not recognized. Objective evidence that a financial asset or group of financial assets are impaired includes: (a) significant financial difficulty of the issuer or obligor; (b) a breach of contract, such as a default or delinquency in interest or principal payments; (c) the lender, for economic or legal reasons relating to the borrower’s financial difficulty, granting

Financial risk management

Financial risk management	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Financial risk management	4. Financial risk management The Company has exposure to the following risks from its use of financial instruments: • credit risk • liquidity risk • market risk • capital risk This note presents information about the Company’s exposure to each of the above risks, the Company’s objectives, policies and processes for measuring and managing risk, and the Company’s management of capital. Further quantitative disclosures are included throughout these consolidated financial statements. (a) Financial risk management 1) Risk management framework The Board of Directors has overall responsibility for the establishment and oversight of the Company’s risk management framework. The Company’s risk management policies are established to identify and analyze the risks faced by the Company, to set appropriate risk limits and controls, and to monitor risks and adherence to limits. Risk management policies and systems are reviewed regularly to reflect changes in market conditions and the Company’s activities. The Company, through its training and management standards and procedures, aims to develop a disciplined and constructive control environment in which all employees understand their roles and obligations. 2) Credit risk Credit risk is the risk of financial loss to the Company if a customer or counterparty to a financial instrument fails to meet its contractual obligations, and arises principally from the Company’s receivables from customers and investment securities. In addition, credit risk arises from finance guarantees. The Company implements a credit risk management policy under which the Company only transacts business with counterparties that have a certain level of credit rate evaluated based on financial condition, historical experience, and other factors. The Company’s exposure to credit risk is influenced mainly by the individual characteristics of each customer. The default risk of a nation or an industry in which a customer operates its business does not have a significant influence on credit risk. The Company has established a credit policy under which each new customer is analyzed individually for creditworthiness. The Company establishes an allowance for impairment that represents its estimate of expected losses in respect of trade and other receivables. The main components of this allowance are a specific loss component that relates to individually significant exposures, and a collective loss component established for companies of similar assets in respect of losses that have been incurred. Credit risk also arises from transactions with financial institutions, and such transactions include transactions of cash and cash equivalents, various deposits, and financial instruments such as derivative contracts. The Company manages its exposure to this credit risk by only entering into transactions with banks that have high international credit ratings. The Company’s treasury department authorizes, manages, and overseas new transactions with financial institutions with whom the Company has no previous relationship. Furthermore, the Company limits its exposure to credit risk of financial guarantee contracts by strictly evaluating their necessity based on internal decision making processes, such as the approval of the board of directors. 3) Liquidity risk Liquidity risk is the risk that the Company will encounter difficulty in meeting the obligations associated with its financial liabilities that are settled by delivering cash or another financial asset. The Company’s approach to managing liquidity is to ensure, as far as possible, that it will always have sufficient liquidity to meet its liabilities when due, under both normal and stressed conditions, without incurring unacceptable losses or risking damage to the Company’s reputation. The Company’s cash flow from business, borrowing or financing is sufficient to meet the cash requirements for the Company’s strategic investments. Management believes that the Company is capable of raising funds by borrowing or financing if the Company is not able to generate cash flow requirements from its operations. The Company has committed borrowing facilities with various banks. 4) Market risk Market risk means that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices. The goal of market risk management is optimization of profit and controlling the exposure to market risk within acceptable limits. ① Currency risk The Company’s policy in respect of foreign currency risks is a natural hedge whereby foreign currency income is offset with foreign currency expenditures. The remaining net exposures after the natural hedge have been hedged using derivative contracts such as forward exchange contracts. In addition, the Company’s derivative transactions are limited to hedging actual foreign currency transactions and speculative hedging is not permitted. Based on this policy, the Company has performed currency risk management specific to various characteristics of different segments. The entities in the steel segment reduces the foreign currency exposure by repayment of foreign currency borrowings subjected to investment in overseas when its maturities come. The entities in the engineering and construction segment have hedged foreign currency risks by using forward exchange contracts. Entities in the trading segment have hedged foreign currency risks by using forward exchange contracts when the foreign currencies received and paid are different. ② Interest rate risk The Company manages the exposure to interest rate risk by adjusting of borrowing structure ratio between borrowings at fixed interest rate and variable interest rate. The Company monitors interest rate risks regularly in order to avoid exposure to interest rate risk on borrowings at variable interest rate. ③ Other market price risk Equity price risk arises from fluctuation of market price of listed equity securities. Management of the Company measures regularly the fair value of listed equity securities and the risk of variance in future cash flow caused by market price fluctuations. Significant investments are managed separately and all buy and sell decisions are approved by management of the Company. (b) Management of capital The fundamental goal of capital management is the maximization of shareholders’ value by means of the stable dividend policy and the retirement of treasury shares. The capital structure of the Company consists of equity and net borrowings (after deducting cash and cash equivalents) and current financial instruments from borrowings. The Company applied the same capital risk management strategy that was applied in the previous period. Net borrowing-to-equity 2017 2018 (in millions of Won) Total borrowings ￦ 21,063,657 20,209,270 Less: Cash and cash equivalents 2,612,530 2,643,865 Net borrowings 18,451,127 17,565,405 Total equity 47,326,725 46,672,614 Net borrowings-to-equity 38.99 % 37.64 %

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Cash and Cash Equivalents	5. Cash and Cash Equivalents Cash and cash equivalents as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Cash ￦ 1,896 1,668 Demand deposits and checking accounts 1,259,813 1,471,891 Time deposits 360,985 538,130 Other cash equivalents 989,836 632,176 ￦ 2,612,530 2,643,865 As of December 31, 2018, cash equivalents amounting to ￦

Trade Accounts and Notes Receiv

Trade Accounts and Notes Receivable	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Trade Accounts and Notes Receivable	6. Trade Accounts and Notes Receivable (a) Trade accounts and notes receivable as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Trade accounts and notes receivable ￦ 8,579,620 8,648,250 Finance lease receivables 10,469 57,487 Unbilled due from customers for contract work 728,007 810,655 Less: Allowance for doubtful accounts (493,533 ) (386,188 ) ￦ 8,824,563 9,130,204 Non-current Trade accounts and notes receivable ￦ 871,432 583,797 Finance lease receivables 734 45,873 Less: Allowance for doubtful accounts (140,596 ) (202,545 ) ￦ 731,570 427,125 Trade accounts and notes receivable sold to financial institutions, for which the derecognition conditions were not met, amounted to ￦ ￦ (b) Finance lease receivables are as follows: Customer Contents 2017 2018 (in millions of Won) Rental contractor (executives and employees) Songdo rental apartment contract ￦ — 103,360 Korea Electric Power Corporation Combined thermal power plant #3~4 10,469 — Hystech.Co. Ltd. Machinery and equipment 734 — ￦ 11,203 103,360 (c) The gross amount and present value of minimum lease payments as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Less than 1 year ￦ 11,771 57,820 1 year – 5 years 828 49,678 Unrealized interest income (1,396 ) (4,138 ) Present value of minimum lease payment ￦ 11,203 103,360

Other Receivables

Other Receivables	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Receivables	7. Other Receivables Other receivables as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Loans ￦ 617,696 236,782 Other accounts receivable 960,543 954,030 Accrued income 179,971 220,066 Deposits 107,137 108,640 Others 18,925 16,201 Less: Allowance for doubtful accounts (248,266 ) (150,090 ) ￦ 1,636,006 1,385,629 Non-current Loans ￦ 874,158 731,344 Other accounts receivable 92,939 155,936 Accrued income 1,663 1,855 Deposits 122,485 152,072 Less: Allowance for doubtful accounts (212,069 ) (177,967 ) ￦ 879,176 863,240

Other Financial Assets

Other Financial Assets	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Financial Assets	8. Other Financial Assets Other financial assets as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Derivatives assets held for trading ￦ 63,912 47,288 Debt securities — 2,987 Financial assets held for trading 1,970 — Available-for-sale 136,141 — Current portion of held-to-maturity 421 — Deposit instruments (*1,2) 1,297,769 1,931,518 Short-term financial instruments (*2) 5,545,667 6,099,303 ￦ 7,045,880 8,081,096 Non-current Derivatives assets held for trading ￦ 4,378 1,795 Equity securities (*3) — 1,238,630 Debt securities — 34,327 Other securities (*3) — 338,106 Available-for-sale (*3) 1,730,753 — Available-for-sale 54,439 — Available-for-sale 56,782 — Held-to-maturity 4,790 — Deposit instruments (*2) 60,542 35,040 ￦ 1,911,684 1,647,898 (*1) As of December 31, 2017 and 2018, ￦ ￦ (*2) As of December 31, 2017 and 2018, financial instruments amounting to ￦ ￦ (*3) As of December 31, 2017 and 2018, ￦ ￦

Inventories

Inventories	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Inventories	9. Inventories (a) Inventories as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Finished goods ￦ 1,526,628 1,886,040 Merchandise 930,558 1,131,416 Semi-finished goods 1,721,130 1,945,567 Raw materials 2,329,268 2,821,972 Fuel and materials 808,016 888,941 Construction inventories 1,692,092 1,372,259 Materials-in-transit 1,818,576 2,245,740 Others 103,144 68,150 10,929,412 12,360,085 Less: Allowance for inventories valuation (135,631 ) (206,782 ) ￦ 10,793,781 12,153,303 (b) The changes of allowance for inventories valuation for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Beginning ￦ 231,378 203,164 135,631 Loss on valuation of inventories 152,249 78,560 141,799 Realization on disposal of inventories (161,458 ) (138,967 ) (69,426 ) Others (19,005 ) (7,126 ) (1,222 ) Ending ￦ 203,164 135,631 206,782

Assets Held for Sale

Assets Held for Sale	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Assets Held for Sale	10. Assets Held for Sale Details of assets held for sale as of December 31, 2017 and 2018 are as follows: 2017 2018 Controlling Subsidiaries (*1) Total Subsidiaries (*2) (in millions of Won) Assets Other financial assets ￦ — — — 778 Property, plant and equipment 392 71,340 71,732 21,076 Others — 36 36 — ￦ 392 71,376 71,768 21,854 (*1) During the year ended December 2017, POSCO ENGINEERING & CONSTRUCTION CO., LTD., a subsidiary of the Company, determined to dispose of the office building, Seomyeon Fiesta, in Busan and classified the related property, plant and equipment amounting to ￦ (*2) During the year ended December 31, 2018, DAESAN (CAMBODIA) Co., Ltd., a subsidiary of the Company, determined to dispose of the land and classified the related property, plant and equipment amounting to ￦

Investments in Associates and J

Investments in Associates and Joint ventures	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Investments in Associates and Joint ventures	11. Investments in Associates and Joint ventures (a) Investments in associates and joint ventures as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Investments in associates ￦ 1,520,441 1,738,692 Investments in joint ventures 2,037,491 1,911,311 ￦ 3,557,932 3,650,003 (b) Details of investments in associates as of December 31, 2017 and 2018 are as follows: Number of shares Ownership (%) Acquisition cost Book value Company 2017 2018 (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources 178,713,975,892 31.27 ￦ 178,787 ￦ 175,553 174,123 POSPower Co., Ltd (*1,2) 4,507,138 34.00 164,757 — 161,477 SNNC 18,130,000 49.00 90,650 110,424 116,922 QSONE Co., Ltd. 200,000 50.00 84,395 85,049 85,550 Chun-cheon Energy Co., Ltd (*2) 16,098,143 45.67 80,491 74,378 62,478 CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd 2,008,000 29.53 10,040 17,252 17,382 Daesung Steel (*4) 108,038 17.54 14,000 15,500 15,644 Incheon-Gimpo Expressway Co., Ltd. (*2,4) 9,032,539 18.26 45,163 31,660 13,329 Keystone NO. 1. Private Equity Fund 13,800,000 40.45 13,800 12,379 11,183 KoFC POSCO HANWHA KB Shared Growth (*4) 6,485 12.50 6,485 6,828 5,739 KONES, Corp. 3,250,000 41.67 6,893 2,827 2,849 BLUE OCEAN Private Equity Fund 333 27.52 33,300 19,620 — UITrans LRT Co., Ltd. (*2) 7,714,380 38.19 38,572 15,841 — Others (46 companies) (*2) 67,325 123,734 634,636 790,410 [Foreign] AES-VCM (*3) — 30.00 164,303 142,348 209,936 South-East Asia Gas Pipeline Company Ltd. 135,219,000 25.04 135,899 197,069 179,459 7623704 Canada Inc. (*4) 114,452,000 10.40 124,341 121,702 126,885 Eureka Moly LLC — 20.00 240,123 79,398 82,447 AMCI (WA) PTY LTD 49 49.00 209,664 63,378 71,086 KOREA LNG LTD. 2,400 20.00 135,205 33,422 43,554 Nickel Mining Company SAS 3,234,698 49.00 157,585 45,905 41,712 NCR LLC — 29.41 40,139 33,738 37,602 PT. Batutua Tembaga Raya 128,285 22.00 21,824 21,823 20,479 Zhongyue POSCO (Qinhuangdao) Tinplate 10,200,000 34.00 9,517 15,617 14,796 PT. Wampu Electric Power (*2) 8,708,400 20.00 10,054 13,391 14,120 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 50 25.00 4,723 6,517 6,478 Others (29 companies) (*2) 111,497 99,728 885,805 948,282 ￦ 1,520,441 1,738,692 (*1) During the year ended December 31, 2018, the Company disposed of 63.53% of shares in POSPower Co., Ltd, which resulted in the Company’s loss of control, and the Company classified the remaining investment as investment in an associate. (*2) As of December 31, 2017 and 2018, investments in associates amounting to ￦ ￦ (*3) As of December 31, 2017 and 2018, shares of PSC Energy Global Co., Ltd., a subsidiary of the Company, are provided as collateral in relation to the associates’ borrowings. (*4) As of December 31, 2018, it was classified as an associate even though the Company’s ownership percentage is less than 20% of ownership percentage since the Company has significant influence over the investee when considering its structure of the Board of Directors and others. (c) Details of investments in joint ventures as of December 31, 2017 and 2018 are as follows: Number of shares Ownership (%) Acquisition cost Book value Company 2017 2018 (in millions of Won) [Domestic] POSCO MITSUBISHI CARBON TECHNOLOGY 11,568,000 60.00 ￦ 115,680 ￦ 110,760 180,192 Others (6 companies) 6,094 9,124 116,854 189,316 [Foreign] Roy Hill Holdings Pty Ltd (*1) 13,117,972 12.50 1,528,672 1,125,133 1,041,600 POSCO-NPS 325,050,000 50.00 364,609 348,836 363,506 KOBRASCO 2,010,719,185 50.00 32,950 108,485 133,449 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — 25.00 61,961 88,305 88,391 DMSA/AMSA (*1) — 4.00 322,596 56,735 26,709 CSP — Compania Siderurgica do Pecem 1,108,696,532 20.00 558,821 146,427 24,832 Others (13 companies) 46,716 43,508 1,920,637 1,721,995 ￦ 2,037,491 1,911,311 (*1) As of December 31, 2017 and 2018, the investments in joint ventures are provided as collateral in relation to the joint ventures’ borrowings. (d) The movements of investments in associates and joint ventures for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Company December 31, Book value Acquisition Dividends Share of Other (decrease) (*1) December 31, Book value (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources Private Equity Fund ￦ 175,690 — — 418 (555 ) 175,553 SNNC 107,859 — — 2,370 195 110,424 QSONE Co., Ltd. 84,799 — (368 ) 618 — 85,049 Chun-cheon Energy Co., Ltd 45,077 27,791 — 1,510 — 74,378 CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd 12,551 — — 4,701 — 17,252 BLUE OCEAN Private Equity Fund 35,752 — — (8,154 ) (7,978 ) 19,620 Daesung Steel 12,302 — — 3,198 — 15,500 Incheon-Gimpo Expressway Co., Ltd. 37,372 — — (6,463 ) 751 31,660 Keystone NO. 1. Private Equity Fund 13,314 — — (886 ) (49 ) 12,379 UITrans LRT Co., Ltd. 17,851 — — (2,010 ) — 15,841 KoFC POSCO HANWHA KB Shared Growth 11,890 — — (197 ) (4,865 ) 6,828 KONES, Corp. 5,641 — — (2,774 ) (40 ) 2,827 POSCO MITSUBISHI CARBON TECHNOLOGY 83,113 — — 27,582 65 110,760 Others (40 companies) 55,061 28,348 (137 ) (7,995 ) (1,858 ) 73,419 698,272 56,139 (505 ) 11,918 (14,334 ) 751,490 [Foreign] AES-VCM 167,141 — (30,798 ) 19,644 (13,639 ) 142,348 South-East Asia Gas Pipeline Company Ltd. 215,996 — (37,016 ) 42,896 (24,807 ) 197,069 7623704 Canada Inc. 137,512 — (7,563 ) 7,468 (15,715 ) 121,702 Eureka Moly LLC 89,601 — — (35 ) (10,168 ) 79,398 AMCI (WA) PTY LTD 70,501 — — (4,299 ) (2,824 ) 63,378 Nickel Mining Company SAS 45,138 — — 424 343 45,905 KOREA LNG LTD. 63,058 — (6,466 ) (70,180 ) 47,010 33,422 NCR LLC 36,738 276 — (60 ) (3,216 ) 33,738 PT. Batutua Tembaga Raya 22,723 — — 260 (1,160 ) 21,823 PT. Wampu Electric Power 8,706 — — 5,927 (1,242 ) 13,391 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 18,008 — — (1,268 ) (1,123 ) 15,617 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,840 — — 303 (626 ) 6,517 Roy Hill Holdings Pty Ltd 1,186,859 — — 46,020 (107,746 ) 1,125,133 POSCO-NPS 393,570 — (17,277 ) 17,173 (44,630 ) 348,836 KOBRASCO 88,308 — (22,135 ) 56,445 (14,133 ) 108,485 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 97,369 — (5,542 ) 1,555 (5,077 ) 88,305 DMSA/AMSA 74,935 13,712 — (22,339 ) (9,573 ) 56,735 CSP - Compania Siderurgica do Pecem 330,463 — — (147,847 ) (36,189 ) 146,427 Others (40 companies) 130,651 22,209 (4,408 ) 46,535 (36,774 ) 158,213 3,184,117 36,197 (131,205 ) (1,378 ) (281,289 ) 2,806,442 ￦ 3,882,389 92,336 (131,710 ) 10,540 (295,623 ) 3,557,932 (*1) Other increase or decrease represents the changes in investments in associates and joint ventures due to disposals, change in capital adjustments effect from translations of financial statements of foreign investees and others. 2) For the year ended December 31, 2018 Company December 31, Acquisition Dividends Share of Other (*1) December 31, (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 175,553 — — (1,430 ) — 174,123 POSPower Co., Ltd — 176,731 — (3,198 ) (12,056 ) 161,477 SNNC 110,424 — — 6,624 (126 ) 116,922 QSONE Co., Ltd. 85,049 — (550 ) 1,051 — 85,550 Chun-cheon Energy Co., Ltd 74,378 — — (11,900 ) — 62,478 CHUNGJU ENTERPRISE CITY 17,252 — — 130 — 17,382 BLUE OCEAN Private Equity Fund 19,620 — — (17,930 ) (1,690 ) — Daesung Steel 15,500 — — 144 — 15,644 Incheon-Gimpo Expressway Co., Ltd. 31,660 — — (18,331 ) — 13,329 Keystone NO. 1. Private Equity Fund 12,379 — — (1,295 ) 99 11,183 UITrans LRT Co., Ltd. 15,841 — — (15,841 ) — — KoFC POSCO HANWHA KB Shared Growth 6,828 — — (1,089 ) — 5,739 KONES, Corp. 2,827 — — 29 (7 ) 2,849 POSCO MITSUBISHI CARBON TECHNOLOGY 110,760 — — 69,594 (162 ) 180,192 Others (52 companies) 73,419 44,629 (784 ) 18,942 (3,348 ) 132,858 751,490 221,360 (1,334 ) 25,500 (17,290 ) 979,726 [Foreign] AES-VCM 142,348 — (26,108 ) 30,096 63,600 209,936 South-East Asia Gas Pipeline Company Ltd. 197,069 — (29,301 ) 17,709 (6,018 ) 179,459 7623704 Canada Inc. 121,702 — (4,509 ) 4,373 5,319 126,885 Eureka Moly LLC 79,398 — — (406 ) 3,455 82,447 AMCI (WA) PTY LTD. 63,378 — — (3,412 ) 11,120 71,086 KOREA LNG LTD. 33,422 — (10,544 ) 10,542 10,134 43,554 Nickel Mining Company SAS 45,905 — — (4,268 ) 75 41,712 NCR LLC 33,738 2,505 — (5,909 ) 7,268 37,602 PT. Batutua Tembaga Raya 21,823 — — (1,817 ) 473 20,479 Zhongyue POSCO (Qinhuangdao) Tinplate 15,617 — — (735 ) (86 ) 14,796 PT. Wampu Electric Power 13,391 — — 177 552 14,120 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,517 — — 23 (62 ) 6,478 Roy Hill Holdings Pty Ltd 1,125,133 — — 59,095 (142,628 ) 1,041,600 POSCO-NPS 348,836 — (22,254 ) 21,536 15,388 363,506 KOBRASCO 108,485 — (37,710 ) 75,170 (12,496 ) 133,449 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 88,305 — — 540 (454 ) 88,391 DMSA/AMSA 56,735 17,973 — (48,802 ) 803 26,709 CSP - Compania Siderurgica do Pecem 146,427 — — (109,714 ) (11,881 ) 24,832 Others (42 companies) 158,213 2,771 (22,588 ) 42,937 (38,097 ) 143,236 2,806,442 23,249 (153,014 ) 87,135 (93,535 ) 2,670,277 ￦ 3,557,932 244,609 (154,348 ) 112,635 (110,825 ) 3,650,003 (*1) Other increase or decrease represents the changes in investments in associates and joint ventures due to disposals, change in capital adjustments effect from translations of financial statements of foreign investees and others. (e) Summarized financial information of associates and joint ventures as of and for the years ended December 31, 2017 and 2018 are as follows: 1) December 31, 2017 Company Assets Liabilities Equity Sales Net (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 562,698 866 561,832 — 1,261 SNNC 705,975 459,519 246,456 576,023 2,417 QSONE Co., Ltd. 248,779 78,680 170,099 15,297 1,236 Chun-cheon Energy Co., Ltd 700,079 539,137 160,942 164,294 (8,250 ) Daesung Steel 169,774 112,795 56,979 70,434 18,230 Incheon-Gimpo Expressway Co., Ltd. 1,132,233 922,338 209,895 — (23,221 ) CHUNGJU ENTERPRISE CITY 76,184 48,072 28,112 77,093 15,921 BLUE OCEAN Private Equity Fund 311,129 188,512 122,617 445,238 (3,345 ) Keystone NO. 1. Private Equity Fund 170,155 133,033 37,122 5,391 (2,070 ) UITrans LRT Co., Ltd. 464,074 384,202 79,872 3,689 (13,263 ) KoFC POSCO HANWHA KB Shared Growth 55,936 1,315 54,621 10,212 (1,578 ) KONES, Corp. 2,766 1,616 1,150 5,379 139 POSCO MITSUBISHI CARBON TECHNOLOGY 478,847 295,052 183,795 154,312 46,138 [Foreign] South-East Asia Gas Pipeline Company Ltd. 1,911,942 1,121,783 790,159 445,682 171,303 7623704 Canada Inc. 1,182,376 9 1,182,367 — 82,344 KOREA LNG LTD. 179,269 86 179,183 34,640 32,446 Nickel Mining Company SAS 465,700 324,687 141,013 179,683 (4,450 ) PT. Batutua Tembaga Raya 336,085 272,542 63,543 195,520 49,091 Zhongyue POSCO (Qinhuangdao) Tinplate 70,437 18,722 51,715 85,850 (3,736 ) PT. Wampu Electric Power 212,095 148,177 63,918 779 29,634 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 70,701 43,588 27,113 84,973 1,210 Roy Hill Holdings Pty Ltd 10,148,416 6,600,900 3,547,516 2,988,372 797,008 POSCO-NPS 697,470 — 697,470 — 32,481 KOBRASCO 252,813 35,843 216,970 179,453 112,890 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 717,472 391,871 325,601 1,245,178 5,978 DMSA/AMSA 5,586,171 4,167,906 1,418,265 630,229 (475,958 ) CSP - Compania Siderurgica do Pecem 4,805,353 4,223,392 581,961 1,290,767 (740,591 ) 2) December 31, 2018 Company Assets Liabilities Equity Sales Net (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 552,760 783 551,977 — 10,249 POSPower Co., Ltd 425,632 35,761 389,871 — (4,536 ) SNNC 645,013 384,586 260,427 656,320 14,229 QSONE Co., Ltd. 249,384 78,285 171,099 16,597 2,101 Chun-cheon Energy Co., Ltd 667,454 525,308 142,146 320,950 (18,796 ) CHUNGJU ENTERPRISE CITY 63,554 35,003 28,551 16,237 439 BLUE OCEAN Private Equity Fund 305,876 174,640 131,236 459,491 (5,294 ) Daesung Steel 169,305 111,502 57,803 75,474 824 Incheon-Gimpo Expressway Co., Ltd. 1,049,629 931,937 117,692 — (92,202 ) Keystone NO. 1. Private Equity Fund 177,024 144,186 32,838 15,507 (3,962 ) UITrans LRT Co., Ltd. 430,227 435,699 (5,472 ) 12,929 (85,344 ) KoFC POSCO HANWHA KB Shared Growth 59,464 1,061 58,403 2,401 (12,313 ) KONES, Corp. 2,618 1,414 1,204 5,167 70 POSCO MITSUBISHI CARBON TECHNOLOGY 537,138 237,563 299,575 300,986 116,049 [Foreign] South-East Asia Gas Pipeline Company Ltd. 1,726,410 1,009,731 716,679 343,471 70,717 7623704 Canada Inc. 1,232,208 1 1,232,207 — 44,320 KOREA LNG LTD. 217,883 110 217,773 54,357 52,720 Nickel Mining Company SAS 465,463 329,084 136,379 207,956 (4,569 ) PT. Batutua Tembaga Raya 332,305 274,580 57,725 128,609 (8,451 ) Zhongyue POSCO (Qinhuangdao) Tinplate 73,515 24,264 49,251 121,104 (2,231 ) PT. Wampu Electric Power 223,009 155,407 67,602 13,461 887 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 61,782 34,740 27,042 85,619 78 Roy Hill Holdings Pty Ltd 9,666,619 6,043,492 3,623,127 3,259,256 497,469 POSCO-NPS 726,810 — 726,810 — 41,812 KOBRASCO 317,842 50,945 266,897 229,340 150,550 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 710,518 384,572 325,946 1,341,849 2,159 DMSA/AMSA 5,562,877 4,171,896 1,390,981 731,127 (529,844 ) CSP - Compania Siderurgica do Pecem 4,194,242 4,192,867 1,375 1,860,198 (542,865 )

Joint Operations

Joint Operations	12 Months Ended
	Dec. 31, 2018
Investments accounted for using equity method [abstract]
Joint Operations	12. Joint Operations Details of significant joint operations that the Company is participating in as a party to a joint arrangement as of December 31, 2018 are as follows: Joint operations Operation Ownership Location Myanmar A-1/A-3 Mineral development and gas production 51.00 Myanmar Offshore midstream Gas transportation facility 51.00 Myanmar Greenhills mine Mine development 20.00 Canada Arctos Anthracite coal project Mine development 50.00 Canada Mt. Thorley J/V Mine development 20.00 Australia POSMAC J/V Mine development 20.00 Australia RUM J/V Mine development 10.00 Australia Hanam-Gamil package public housing project Construction 7.70 Korea Hanam-Gamil district B6, C2, C3 block Public Construction 27.00 Korea Sejong 2-1 Construction 37.00 Korea Yongin-Giheung Station area city development project Construction 61.00 Korea Korean wave world complex land multi-purpose building development project Construction 33.30 Korea Sejong 4-1 Construction 60.00 Korea

Investment Property, Net

Investment Property, Net	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Investment Property, Net	13. Investment Property, Net (a) Investment property as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition cost Accumulated depreciation and impairment loss Book value Acquisition cost Accumulated depreciation and impairment loss Book value (in millions of Won) Land ￦ 360,402 — 360,402 295,328 (16,743 ) 278,585 Buildings 727,022 (92,982 ) 634,040 681,518 (110,183 ) 571,335 Structures 7,717 (1,436 ) 6,281 3,327 (1,919 ) 1,408 Construction-in-progress 64,191 — 64,191 101,665 (24,378 ) 77,287 ￦ 1,159,332 (94,418 ) 1,064,914 1,081,838 (153,223 ) 928,615 As of December 31, 2018, the fair value of investment property is ￦ (b) Changes in the carrying amount of investment property for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Disposals Depreciation Others (*1) Ending (in millions of Won) Land ￦ 392,723 20,941 (37,725 ) — (15,537 ) 360,402 Buildings 671,539 38,831 (9,506 ) (23,450 ) (43,374 ) 634,040 Structures 2,147 — — (591 ) 4,725 6,281 Construction-in-progress 51,311 17,648 — — (4,768 ) 64,191 ￦ 1,117,720 77,420 (47,231 ) (24,041 ) (58,954 ) 1,064,914 (*1) Includes reclassification resulting from changing purpose of use, adjustment of foreign currency translation difference and others. 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Depreciation (*1) Others (*2) Ending (in millions of Won) Land ￦ 360,402 1,327 (26,826 ) (16,743 ) (39,575 ) 278,585 Buildings 634,040 727 (32,807 ) (28,358 ) (2,267 ) 571,335 Structures 6,281 — — (603 ) (4,270 ) 1,408 Construction-in-progress 64,191 42,052 — (24,948 ) (4,008 ) 77,287 ￦ 1,064,914 44,106 (59,633 ) (70,652 ) (50,120 ) 928,615 (*1) Includes impairment loss on investment property recognized by each of the consolidated subsidiaries, including the office for rent of POSCO(Dalian) IT Center Development Co., Ltd. amounting to ￦ (*2) Includes reclassification resulting from changing purpose of use, adjustment of foreign currency translation difference and others.

Property, Plant and Equipment,

Property, Plant and Equipment, Net	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Property, Plant and Equipment, Net	14. Property, Plant and Equipment, Net (a) Property, plant and equipment as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition Accumulated Government Book value Acquisition cost Accumulated loss Government grants Book value (in millions of Won) Land ￦ 2,534,102 (6,452 ) — 2,527,650 2,553,957 (5,955 ) — 2,548,002 Buildings 9,311,426 (4,433,996 ) (412 ) 4,877,018 9,146,294 (4,743,449 ) (393 ) 4,402,452 Structures 5,452,713 (2,686,802 ) (59 ) 2,765,852 5,884,277 (2,966,304 ) (49 ) 2,917,924 Machinery and equipment 46,669,612 (27,301,410 ) (245 ) 19,367,957 47,610,225 (29,091,754 ) (342 ) 18,518,129 Vehicles 296,815 (263,884 ) (70 ) 32,861 302,767 (271,381 ) (45 ) 31,341 Tools 380,144 (315,446 ) (1,058 ) 63,640 399,638 (333,387 ) (87 ) 66,164 Furniture and fixtures 643,779 (498,192 ) (148 ) 145,439 638,553 (502,215 ) (51 ) 136,287 Finance lease assets 243,160 (97,903 ) — 145,257 213,873 (76,309 ) — 137,564 Bearer plants 70,031 (4,516 ) — 65,515 88,773 (8,002 ) — 80,771 Construction-in- 1,897,885 — (5,539 ) 1,892,346 1,964,267 (778,373 ) (6,255 ) 1,179,639 ￦ 67,499,667 (35,608,601 ) (7,531 ) 31,883,535 68,802,624 (38,777,129 ) (7,222 ) 30,018,273 (b) Changes in the carrying amount of property, plant and equipment for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Disposals Depreciation Impairment (*1) Others (*2) Ending (in millions of Won) Land ￦ 2,601,208 3,477 (18,226 ) — — (58,809 ) 2,527,650 Buildings 4,995,631 53,961 (5,782 ) (347,419 ) (14,112 ) 194,739 4,877,018 Structures 2,908,480 18,943 (2,558 ) (212,643 ) (33,586 ) 87,216 2,765,852 Machinery and equipment 20,318,390 194,653 (93,210 ) (2,189,624 ) (27,811 ) 1,165,559 19,367,957 Vehicles 46,699 9,982 (1,623 ) (17,363 ) (4,977 ) 143 32,861 Tools 71,380 16,424 (976 ) (28,516 ) (23 ) 5,351 63,640 Furniture and fixtures 132,406 61,597 (1,296 ) (48,400 ) (16 ) 1,148 145,439 Finance lease assets 159,013 4,760 (453 ) (14,810 ) — (3,253 ) 145,257 Bearer plants — — — (4,830 ) — 70,345 65,515 Construction-in- 2,537,132 1,894,067 (817 ) — (36,706 ) (2,501,330 ) 1,892,346 ￦ 33,770,339 2,257,864 (124,941 ) (2,863,605 ) (117,231 ) (1,038,891 ) 31,883,535 (*1) As of December 31, 2017, due to the existence of indicators for impairment such as continuous operating loss on Suncheon Bay Personal Rapid Transit business of the Suncheon Eco Trans Co., Ltd, a subsidiary of the Company, the Company performed impairment test and recognized impairment loss of ￦ ￦ (*2) Represents assets transferred from construction-in-progress 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Depreciation Impairment (*1,2) Others (*3) Ending (in millions of Won) Land ￦ 2,527,650 28,998 (26,157 ) — 6,399 11,112 2,548,002 Buildings 4,877,018 46,129 (21,501 ) (331,688 ) (73,523 ) (93,983 ) 4,402,452 Structures 2,765,852 18,749 (2,834 ) (220,218 ) (6,652 ) 363,027 2,917,924 Machinery and equipment 19,367,957 145,220 (62,135 ) (2,224,000 ) (143,293 ) 1,434,380 18,518,129 Vehicles 32,861 8,538 (1,149 ) (14,835 ) (56 ) 5,982 31,341 Tools 63,640 21,337 (1,867 ) (26,421 ) (206 ) 9,681 66,164 Furniture and fixtures 145,439 32,258 (577 ) (51,835 ) (1,494 ) 12,496 136,287 Finance lease assets 145,257 28,466 (420 ) (19,224 ) — (16,515 ) 137,564 Bearer plants 65,515 — — (3,636 ) — 18,892 80,771 Construction-in-progress 1,892,346 1,884,125 (23,814 ) — (778,373 ) (1,794,645 ) 1,179,639 ￦ 31,883,535 2,213,820 (140,454 ) (2,891,857 ) (997,198 ) (49,573 ) 30,018,273 (*1) During 2018, the Controlling Company evaluated future economic performance of its Synthetic Natural Gas (SNG) facility that was still in trial run stage. Considering the continuous decline in LNG price, increase in coal prices and the need for additional capital investment in the SNG facility, the Controlling Company concluded that the profitability for the SNG facility is unlikely to be sustainable and decided to terminate the operation of SNG facility as of December 31, 2018. The property, plant and equipment in the SNG facility are primarily comprised of machinery and equipment, among which assets with a carrying value of ￦ re-used For the assets for which sale is probable, the recoverable amount is determined based on fair value less cost of disposal. Fair value was measured using cost approach, which is based on an estimated of the current cost to purchase or replace the asset less applicable depreciation and obsolescence. Specifically, the Controlling Company used indirect cost approach to estimate the replacement cost for a new asset by applying asset specific inflation factors to the asset’s historical cost. Then the Controlling Company estimates and deducts depreciation for physical deterioration. Depreciation factors are applied primarily based on estimated useful life of the asset and declining balance depreciation method. The fair value measurement of assets in SNG facility is considered to be level 3 because significant inputs used in the estimate, such as asset specific inflation factors and estimated useful lives, are unobservable. As a result of the impairment test, the Company recognized an impairment loss of ￦ The Controlling Company also has recognized an impairment loss amounting to ￦ (*2) As of December 31, 2018, POSCO ENERGY CO., LTD., as a subsidiary, performed an impairment test due to the consecutive operating loss of the fuel cell business, and recognized impairment losses amounting to ￦ (*3) Represents assets transferred from construction-in-progress (c) Borrowing costs capitalized and the capitalized interest rate for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Weighted average expenditure ￦ 1,180,563 628,595 Borrowing costs capitalized 37,261 22,619 Capitalization rate (%) 1.74 ~ 3.45 2.51 ~ 3.90 (d) Property, plant and equipment and investment property pledged as collateral as of December 31, 2017 and 2018 are as follows: Book value Collateral right holder 2017 2018 (*2) (in millions of Won) Land (*1) Korean Development Bank and others ￦ 822,057 769,843 Buildings and structures (*1) Korean Development Bank and others 1,678,403 1,522,129 Machinery and equipment Korean Development Bank and others 3,527,420 3,419,528 Construction-in-progress Korean Development Bank and others 15,389 — ￦ 6,043,269 5,711,500 (*1) Investment property and other assets (land-use (*2) As of December 31, 2018, the pledged amount is ￦

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets, Net	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Goodwill and Other Intangible Assets, Net	15. Goodwill and Other Intangible Assets, Net (a) Goodwill and other intangible assets as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition Accumulated Government Book value Acquisition Accumulated Government Book value (in millions of Won) Goodwill ￦ 1,604,288 (254,450 ) — 1,349,838 1,603,308 (478,159 ) — 1,125,149 Intellectual property rights 3,140,159 (690,966 ) — 2,449,193 3,300,638 (901,113 ) — 2,399,525 Premium in rental 139,873 (21,563 ) — 118,310 158,338 (23,545 ) — 134,793 Development expense 397,129 (316,892 ) (19 ) 80,218 445,752 (346,589 ) — 99,163 Port facilities usage rights 705,692 (396,319 ) — 309,373 724,375 (419,294 ) — 305,081 Exploration and evaluation assets 296,320 (90,376 ) — 205,944 285,845 (93,715 ) — 192,130 Customer relationships 857,624 (390,679 ) — 466,945 860,951 (439,178 ) — 421,773 Power generation permit 539,405 — — 539,405 — — — — Other intangible assets 1,006,219 (573,152 ) (24 ) 433,043 1,115,742 (622,417 ) (114 ) 493,211 ￦ 8,686,709 (2,734,397 ) (43 ) 5,952,269 8,494,949 (3,324,010 ) (114 ) 5,170,825 (b) The changes in carrying amount of goodwill and other intangible assets for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Business Disposals Amortization Impairment Others (*2) Ending (in millions of Won) Goodwill ￦ 1,375,131 — — — — (21,750 ) (3,543 ) 1,349,838 Intellectual property rights 2,521,171 167,580 47,625 (450 ) (217,932 ) (74,524 ) 5,723 2,449,193 Premium in rental (*1) 119,039 6,006 — (3,666 ) (611 ) (1,661 ) (797 ) 118,310 Development expense 117,012 3,479 — (1,179 ) (66,847 ) (694 ) 28,447 80,218 Port facilities usage rights 256,617 — — — (19,912 ) — 72,668 309,373 Exploration and evaluation assets 162,268 91,548 — — — (56,519 ) 8,647 205,944 Customer relationships 514,245 — — — (46,508 ) — (792 ) 466,945 Power generation permit 539,405 — — — — — — 539,405 Other intangible assets 483,841 84,502 — (1,641 ) (57,964 ) (11,829 ) (63,866 ) 433,043 ￦ 6,088,729 353,115 47,625 (6,936 ) (409,774 ) (166,977 ) 46,487 5,952,269 (*1) Premium in rental includes memberships with indefinite useful lives. (*2) Represents assets transferred from construction-in-progress 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Amortization Impairment Others (*3) Ending (in millions of Won) Goodwill ￦ 1,349,838 — — — (223,709 ) (980 ) 1,125,149 Intellectual property rights 2,449,193 334,667 (18,619 ) (198,282 ) (96,475 ) (70,959 ) 2,399,525 Premium in rental (*1) 118,310 36,196 (15,675 ) (330 ) (4,218 ) 510 134,793 Development expense 80,218 4,248 (32 ) (37,305 ) (411 ) 52,445 99,163 Port facilities usage rights 309,373 — — (22,975 ) — 18,683 305,081 Exploration and evaluation assets 205,944 2,654 — — (3,339 ) (13,129 ) 192,130 Customer relationships 466,945 — — (48,499 ) — 3,327 421,773 Power generation permit 539,405 — — — — (539,405 ) — Other intangible assets 433,043 164,594 (1,644 ) (49,190 ) (8,844 ) (44,748 ) 493,211 ￦ 5,952,269 542,359 (35,970 ) (356,581 ) (336,996 ) (594,256 ) 5,170,825 (*1) Premium in rental includes memberships with indefinite useful lives. (*2) During the year ended December 31, 2018, the Company disposed of a portion of shares of its subsidiary, POSPower Co., Ltd, which resulted in the Company’s loss of control, and derecognition of corresponding intangible assets. (*3) Represents assets transferred from construction-in-progress (c) For the purpose of impairment testing, goodwill is allocated to individually operating entities which are determined to be CGUs. The goodwill amounts as of December 31, 2017 and 2018 are as follows: Reportable segments Total number of CGUs 2017 2018 CGUs 2017 2018 (in millions of Won) Steel 7 7 POSCO VST CO., LTD. ￦ 36,955 36,955 Others 12,494 12,484 Trading 2 2 POSCO DAEWOO Corporation (*1) 1,165,030 1,006,879 PT. Bio Inti Agrindo 7,099 6,902 Others — 16 E&C 2 2 POSCO ENGINEERING (*2) 90,426 24,868 POSCO Center Beijing 157 155 POSCO ENERGY CO., LTD. 26,471 26,471 Others 5 5 Others 11,206 10,419 16 16 ￦ 1,349,838 1,125,149 (*1) Recoverable amounts of POSCO DAEWOO Corporation are determined based on its value in use. As of December 31, 2018, value in use is estimated by applying a 7.84% discount rate and a 2.0% terminal growth rate after 5 years, based on management’s business plan. The terminal growth rate does not exceed long-term average growth rate of its industry. Impairment loss on goodwill of ￦ Value in use of the CGU was affected by the assumptions such as discount rate and terminal growth used in discount cash flow model. When the discount rate increases by 0.25%, value in use will be decreased by ￦ ￦ (*2) Recoverable amounts of POSCO ENGINEERING & CONSTRUCTION CO., LTD are determined based on its value in use. As of December 31, 2018, value in use is estimated by applying a 9.1% discount rate within 5 years, the period for the estimated future cash flows, based on management’s business plan and by no applying a terminal growth rate. Impairment loss on goodwill of ￦ Value in use of the CGU was affected by the assumptions such as discount rate and terminal growth used in discount cash flow model. When the discount rate increases by 0.25%, value in use will be decreased by 2.72% and when the terminal growth rate decreases by 0.25%, value in use will be decreased by 1.76%.

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Assets	16. Other Assets Other current assets and other non-current 2017 2018 (in millions of Won) Current Advance payment ￦ 661,779 539,894 Prepaid expenses 143,032 123,770 Firm commitment asset 15,115 11,246 Others 1,316 9,554 821,242 684,464 Non-current Long-term advance payment 24,201 24,280 Long-term prepaid expenses 333,153 334,918 Others (*1) 131,657 149,566 ￦ 489,011 508,764 (*1) As of December 31, 2017 and 2018, the Company recognized tax assets amounting to ￦ ￦

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Borrowings	17. Borrowings (a) Short-term borrowings and current portion of long-term borrowings as of December 31, 2017 and 2018 are as follows: Bank Issuance date Maturity date Interest 2017 2018 (in millions of Won) Short-term borrowings Bank overdrafts JP Morgan and January, 2017~ January, 2019~ 2.7~8.9 ￦ 217,879 294,364 Short-term borrowings HSBC and others January, 2018~ January, 2019~ 0.3~10.1 7,956,939 7,193,416 8,174,818 7,487,780 Current portion of long-term liabilities Current portion of long-term borrowings Export-Import bank of Korea and others September, 2011~ February, 2019~ 0.5~8.8 1,407,123 1,234,915 Current portion of debentures Korea Development August, 2009~ February, 2019~ 1.8~6.3 1,693,974 1,568,108 Less: Current portion of discount on debentures issued (1,399 ) (1,184 ) 3,099,698 2,801,839 ￦ 11,274,516 10,289,619 (b) Long-term borrowings, excluding current portion as of December 31, 2017 and 2018 are as follows: Bank Issuance date Maturity date Interest 2017 2018 (in millions of Won) Long-term borrowings Export-Import bank of Korea and others September, 2001~ March, 2020~ 0.2~8.8 ￦ 4,839,199 4,499,199 Less: Present value discount (36,459 ) (30,526 ) Bonds KB Securities and others October, 2010~ April, 2020~ 1.9~5.3 4,999,575 5,469,580 Less: Discount on debentures issued (13,174 ) (18,602 ) ￦ 9,789,141 9,919,651 (c) Assets pledged as collateral in regards to the borrowings as of December 31, 2018 are as follows: Bank Book value Pledged (in millions of Won) Cash and cash equivalents Shinhan Bank ￦ 8,296 8,296 Property, plant and equipment and Investment (*1) Korea Development Bank and others 5,592,627 5,304,861 Trade accounts and notes receivable Korea Development Bank and others 157,617 157,617 Inventories Export-Import Bank of Korea and others 205,433 163,233 Financial instruments Kookmin Bank and others 40,664 40,664 ￦ 6,004,637 5,674,671 (*1) Includes other assets such as right to use land.

Other Payables

Other Payables	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Payables	18. Other Payables Other payables as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Accounts payable ￦ 800,374 783,562 Accrued expenses 653,923 720,773 Dividend payable 7,213 8,673 Finance lease liabilities 17,763 10,152 Withholdings 274,188 196,937 ￦ 1,753,461 1,720,097 Non-current Accounts payable ￦ 4,632 1,624 Accrued expenses 14,234 19,021 Finance lease liabilities 75,255 84,602 Long-term withholdings 53,629 43,621 ￦ 147,750 148,868

Other Financial Liabilities

Other Financial Liabilities	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Financial Liabilities	19. Other Financial Liabilities Other financial liabilities as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Derivatives liabilities ￦ 69,872 27,328 Financial guarantee liabilities 59,940 50,472 ￦ 129,812 77,800 Non-current Derivatives liabilities ￦ 85,638 46,429 Financial guarantee liabilities 28,467 17,733 ￦ 114,105 64,162

Provisions

Provisions	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Provisions	20. Provisions (a) Provisions as of December 31, 2017 and 2018 are as follows: 2017 2018 Current Non-current Current Non-current (in millions of Won) Provision for bonus payments ￦ — 46,514 26,964 Provision for construction warranties 11,804 106,232 11,842 130,391 Provision for legal contingencies and claims (*1) 495 36,269 16,981 55,716 Provision for the restoration (*2) 12,273 121,917 9,379 79,789 Others (*3,4) 37,203 212,754 213,737 138,176 ￦ 477,172 298,453 431,036 (*1) The Company recognized probable outflow of resources amounting to ￦ ￦ (*2) Due to contamination of lands near the Company’s magnesium smelting plant located in Gangneung province and others, the Company recognized present values of estimated costs for recovery, ￦ (*3) As of December 31, 2017 and 2018, POSCO ENERGY CO., LTD., a subsidiary of the Company, recognized ￦ ￦ (*4) As of December 31, 2017 and 2018, the amount includes a provision of ￦ ￦ (b) The following are the key assumptions concerning the future and other key sources of estimation uncertainties at the end of the reporting period. Key assumptions for the estimation Provision for bonus payments Estimations based on financial performance and service provided Provision for construction warranties Estimations based on historical warranty data Provision for legal contingencies and claims Estimations based on the degree of probability of an unfavorable outcome and the ability to make a sufficient reliable estimate of the amount of loss (c) Changes in provisions for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Increase Utilization Reversal Others (*1) Ending (in millions of Won) Provision for bonus payments ￦ 42,986 74,728 (64,319 ) (3,035 ) (1,189 ) 49,171 Provision for construction warranties 96,709 40,916 (18,006 ) (2,502 ) 919 118,036 Provision for legal contingencies and claims 84,846 27,459 (70,156 ) (1,749 ) (3,636 ) 36,764 Provision for the restoration 62,594 63,438 (8,530 ) — 16,688 134,190 Others 165,469 161,054 (64,850 ) (20,199 ) 8,483 249,957 ￦ 452,604 367,595 (225,861 ) (27,485 ) 21,265 588,118 (*1) Includes adjustments of foreign currency translation differences and others. 2) For the year ended December 31, 2018 Beginning Increase Utilization Reversal Others (*1) Ending (in millions of Won) Provision for bonus payments ￦ 49,171 88,879 (60,723 ) (3,856 ) 7 73,478 Provision for construction warranties 118,036 56,560 (24,608 ) (7,660 ) (95 ) 142,233 Provision for legal contingencies and claims 36,764 45,789 (6,066 ) (3,399 ) (391 ) 72,697 Provision for the restoration 134,190 14,912 (9,212 ) (47,682 ) (3,040 ) 89,168 Others 249,957 367,332 (118,388 ) (216,668 ) 69,680 351,913 ￦ 588,118 573,472 (218,997 ) (279,265 ) 66,161 729,489 (*1) Includes adjustments of foreign currency translation differences and others.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Employee Benefits	21. Employee Benefits (a) Defined contribution plans The expenses related to post-employment benefit plans under defined contribution plans for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Expense related to post-employment benefit plans under defined contribution plans ￦ 30,344 35,538 42,825 (b) Defined benefit plans 1) The amounts recognized in relation to net defined benefit liabilities in the statements of financial position as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Present value of funded obligations ￦ 1,826,907 2,117,829 Fair value of plan assets (*1) (1,714,166 ) (1,997,717 ) Present value of non-funded 16,228 19,332 Net defined benefit liabilities ￦ 128,969 139,444 (*1) As of December 31, 2017 and 2018, the Company recognized net defined benefit assets amounting to ￦ ￦ 2) Changes in present value of defined benefit obligations for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Defined benefit obligations at the beginning of period ￦ 1,733,020 1,843,135 Current service costs 209,612 212,323 Interest costs 35,830 54,950 Remeasurements : 51,994 212,678 — Gain from change in financial assumptions (50,218 ) 173,084 — Loss (gain) from change in demographic assumptions 15,952 526 — Others 86,260 39,068 Benefits paid (185,220 ) (189,165 ) Others (2,101 ) 3,240 Defined benefit obligations at the end of period ￦ 1,843,135 2,137,161 3) Changes in fair value of plan assets for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Fair value of plan assets at the beginning of period ￦ 1,693,118 1,714,166 Interest on plan assets 45,516 50,784 Remeasurement of plan assets (17,190 ) (19,761 ) Contributions to plan assets 164,828 408,326 Benefits paid (168,643 ) (163,112 ) Others (3,463 ) 7,314 Fair value of plan assets at the end of period ￦ 1,714,166 1,997,717 The Company expects to make an estimated contribution of ￦ 4) The fair value of plan assets as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Equity instruments ￦ 41,218 3,151 Debt instruments 367,027 692,825 Deposits 1,254,571 1,244,802 Others 51,350 56,939 ￦ 1,714,166 1,997,717 5) The amounts recognized in consolidated statements of comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Current service costs ￦ 285,706 209,612 212,323 Net interest costs (*1) 1,901 (9,686 ) 4,166 ￦ 287,607 199,926 216,489 (*1) The actual return on plan assets amounted to ￦ ￦ ￦ The above expenses by function were as follows: 2016 2017 2018 (in millions of Won) Cost of sales ￦ 161,810 131,724 150,822 Selling and administrative expenses 124,994 67,424 64,505 Others 803 778 1,162 ￦ 287,607 199,926 216,489 6) Accumulated actuarial gains (losses), net of tax recognized in other comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Beginning ￦ (272,152 ) (251,612 ) (299,155 ) Current actuarial gains (losses) 20,540 (47,543 ) (173,489 ) Ending ￦ (251,612) (299,155 ) (472,644 ) 7) The principal actuarial assumptions as of December 31, 2017 and 2018 are as follows: 2017 2018 (%) Discount rate 2.70~7.75 2.24~10.03 Expected future increase in salaries (*1) 1.04~10.00 2.54~10.00 (*1) The expected future increase in salaries is based on the average salary increase rate for the past 3~5 years. All assumptions are reviewed at the end of the reporting period. Additionally, the total estimated defined benefit obligation includes actuarial assumptions associated with the long-term characteristics of the defined benefit plan. 8) Reasonably possible changes at the reporting date to one of the relevant actuarial assumptions, holding the other assumptions constant, would have affected the defined benefit obligation by the amounts shown below: 1% Increase 1% Decrease Amount Percentage (%) Amount Percentage (%) (in millions of Won) Discount rate ￦ (143,793 ) (6.7 ) 166,225 7.8 Expected future increase in salaries 167,278 7.8 (147,232 ) (6.9 ) 9) As of December 31, 2018 the maturity of the expected benefit payments are as follows: Within 1 year - 5 years - 10 years - After Total (in millions of Won) Benefits paid ￦ 110,168 735,172 836,318 795,347 491,384 2,968,389 The maturity analysis of the defined benefit obligation was nominal amounts of defined benefit obligations using expected remaining period of service of employees.

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Liabilities	22. Other Liabilities Other liabilities as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Due to customers for contract work ￦ 782,968 641,064 Advances received 1,183,108 1,130,910 Unearned revenue 7,121 49,805 Withholdings 221,940 233,981 Firm commitment liability 12,192 24,373 Others 33,590 10,174 ￦ 2,240,919 2,090,307 Non-current Advances received 357,981 148,081 Unearned revenue 18,440 42,992 Others 10,010 59,359 ￦ 386,431 250,432

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Financial Instruments	23. Financial Instruments (a) Classification and fair value of financial instruments 1) The carrying amount and the fair values of financial assets and financial liabilities by fair value hierarchy as of December 31, 2017 and 2018 are as follows: ① December 31, 2017 Fair value Book value Level 1 Level 2 Level 3 Total (in millions of Won) Financial assets Financial assets at fair value through profit or loss Financial assets held for trading ￦ 1,970 — 1,970 — 1,970 Derivatives assets held for trading 65,051 — 65,051 — 65,051 Derivative hedging instruments 3,239 — 3,239 — 3,239 Available-for-sale 1,978,115 1,080,291 17,812 880,012 1,978,115 Held-to-maturity 5,211 — — — — Loans and receivables (*1) Cash and cash equivalents 2,612,530 — — — — Trade accounts and notes receivable 8,898,176 — — — — Loans and other receivables 9,099,444 — — — — ￦ 22,663,736 1,080,291 88,072 880,012 2,048,375 Financial liabilities Financial liabilities at fair value through profit or loss Derivative liabilities held for trading ￦ 142,280 — 142,280 — 142,280 Derivative hedging instruments 13,230 — 13,230 — 13,230 Financial liabilities measured at amortized cost (*1) Trade accounts and notes payable 3,477,678 — — — — Borrowings 21,063,657 — 21,217,415 — 21,217,415 Financial guarantee liabilities 88,407 — — — — Others 1,865,683 — — — — ￦ 26,650,935 — 21,372,925 — 21,372,925 (*1) Fair value of financial assets and liabilities measured at amortized cost except borrowings approximates carrying amounts. ② December 31, 2018 Fair value Book value Level 1 Level 2 Level 3 Total (in millions of Won) Financial assets Fair value through profit or loss Derivative assets ￦ 16,662 — 16,662 — 16,662 Short-term financial instruments 6,099,303 — 6,099,303 — 6,099,303 Debt securities 27,229 — — 27,229 27,229 Other securities 338,106 1,224 5,205 331,677 338,106 Other receivables 2,000 — — 2,000 2,000 Derivative hedging instruments (*2) 32,421 — 32,421 — 32,421 Fair value through other comprehensive income Equity securities 1,238,630 891,514 — 347,116 1,238,630 Debt securities 1,638 — — 1,638 1,638 Financial assets measured at amortized cost (*1) Cash and cash equivalents 2,643,865 — — — — Trade accounts and notes receivable 8,819,617 — — — — Other receivables 1,843,381 — — — — Debt securities 8,447 — — — — Deposit instruments 1,966,558 — — — — ￦ 23,037,857 892,738 6,153,591 709,660 7,755,989 Financial liabilities Fair value through profit or loss Derivative liabilities ￦ 60,047 — 60,047 — 60,047 Derivative hedging instruments (*2) 13,710 — 13,710 — 13,710 Financial liabilities measured at amortized cost (*1) Trade accounts and notes payable 4,035,960 — — — — Borrowings 20,209,270 — 20,377,105 — 20,377,105 Financial guarantee liabilities 68,205 — — — — Others 1,803,353 — — — — ￦ 26,190,545 — 20,450,862 — 20,450,862 (*1) Fair value of financial assets and liabilities measured at amortized cost except borrowings approximates carrying amounts. (*2) The Company applies hedge accounting which uses forward contracts as hedging instrument in order to hedge the risk of changes in fair value of product prices regarding firm commitments or purchase commitments. Also, the Company applies cash flow accounting which uses currency swap as hedging instrument in order to hedge the risk of changes in foreign currency which influences cash flow from borrowings. 2) Financial assets and financial liabilities classified as fair value hierarchy Level 2 Fair values of derivatives are measured using the derivatives instrument valuation model such as discounted cash flow method and others. Inputs of the financial instrument valuation model include forward rate, interest rate and others. It may change depending on the type of derivatives and the nature of the underlying assets. 3) Financial assets and financial liabilities classified as fair value hierarchy Level 3 ① Value measurement method and significant but not observable inputs for the financial assets classified as fair value hierarchy Level 3 as of December 31, 2018 are as follows: Fair value Valuation technique Inputs Range of inputs Effect on fair value (in millions of Won) Financial assets at fair value ￦ 303,377 Discounted cash flows Growth rate 0% ~ 0.5% As growth rate increases, fair value increases Discount rate 6.4% ~ 13.8% As discount rate increases, fair value decreases 23,747 Proxy firm valuation method Price multiples 1.085 ~ 5.245 As price multiples increases, fair value increases 382,536 Asset value approach — — — ② Sensitivity analysis of financial assets and financial liabilities classified as Level 3 of fair value hierarchy If other inputs remain constant as of December 31, 2018 and one of the significant but not observable input is changed, the effect on fair value measurement is as follows: Input variable Favorable Unfavorable (in millions of Won) Financial assets at fair value Fluctuation 0.5% of growth rate ￦ 1,563 958 Fluctuation 0.5% of discount rate 17,332 15,715 ③ Changes in fair value of financial assets and financial liabilities classified as Level 3 for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Beginning ￦ 349,090 880,012 Acquisition and others 658,359 134,325 Gain (loss) on valuations of derivatives (10,346 ) (34,555 ) Other comprehensive income (loss) 35,126 26,771 Impairment (107,934 ) — Disposal and others (44,283 ) (296,893 ) Ending ￦ 880,012 709,660 4) Finance income and costs by category of financial instrument for the years ended December 31, 2016, 2017 and 2018 were as follows: ① For the year ended December 31, 2016 Finance income and costs Other Interest Gain and Gain and Gain and Impairment Others Total (in millions of Won) Derivatives assets ￦ — 57,411 — 310,625 — — 368,036 — Available-for-sale 431 — — 127,524 (248,404 ) 41,000 (79,449 ) 310,608 Held-to-maturity 266 — — — — 38 304 — Loans and receivables 181,778 — 140,751 (17,854 ) — (172 ) 304,503 — Derivatives liabilities — (72,976 ) — (332,415 ) — — (405,391 ) — Financial liabilities measured at (658,726 ) — (283,059 ) (61 ) — (28,367 ) (970,213 ) — ￦ (476,251 ) (15,565 ) (142,308 ) 87,819 (248,404 ) 12,499 (782,210 ) 310,608 ② Finance income and costs Interest Gain and Gain and Gain and Impairment Others Total Other (in millions of Won) Financial assets held for trading ￦ — 16 — — — — 16 — Derivatives assets — (99,942 ) — 206,362 — — 106,420 (143 ) Available-for-sale 60 — — 418,789 (123,214 ) 92,961 388,596 (31,389 ) Held-to-maturity 236 — — — — 7 243 — Loans and receivables 212,155 — (607,837 ) (32,456 ) — (304 ) (428,442 ) — Derivatives liabilities — (61,809 ) — (231,908 ) — — (293,717 ) — Financial liabilities measured (653,115 ) — 777,935 — — (9,546 ) 115,274 — ￦ (440,664 ) (161,735 ) 170,098 360,787 (123,214 ) 83,118 (111,610 ) (31,532 ) ③ Finance income and costs Interest Gain and Gain and Gain and Others Total Other comprehensive (in millions of Won) Financial assets at fair value through profit or loss ￦ 140,116 (43,293 ) — 11,919 3,644 112,386 — Derivative assets — 47,720 — 233,187 — 280,907 — Financial assets at fair value through other comprehensive income — — — — 59,701 59,701 (149,188 ) Financial assets measured at amortized cost 197,142 — 234,606 (39,970 ) (370 ) 391,408 — Derivative liabilities — 8,592 — (194,446 ) — (185,854 ) (212 ) Financial liabilities measured at amortized cost (741,296 ) — (438,708 ) — (16,990 ) (1,196,994 ) — ￦ (404,038 ) 13,019 (204,102 ) 10,690 45,985 (538,446 ) (149,400 ) (b) Credit risk 1) Credit risk exposure The carrying amount of financial assets represents the Company’s maximum exposure to credit risk. The maximum exposure to credit risk as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Cash and cash equivalents ￦ 2,612,530 2,643,865 Derivative assets 68,290 49,083 Short-term financial instrument 5,545,667 6,099,303 Debt securities — 37,314 Other securities — 338,106 Financial assets held for trading 1,970 — Available-for-sale 192,866 — Held-to-maturity 5,211 — Other receivables 2,195,466 1,845,381 Trade accounts and notes receivable 8,898,176 8,819,617 Deposit instruments 1,358,311 1,966,558 ￦ 20,878,487 21,799,227 The Company provided financial guarantee for the repayment of loans of associates, joint ventures and third parties. As of December 31, 2017 and 2018, the maximum exposure to credit risk related to the financial guarantee amounted to ￦ ￦ 2) Impairment losses on financial assets The Company assesses expected credit losses by estimating the default rate based on the credit loss experience of prior periods and overdue conditions and considers the credit default swap (CDS) premium to reflect changes in credit risk by sector. For credit-impaired assets and significant receivables where the credit risk is significantly increased, credit losses are individually assessed. ① 2017 2018 (in millions of Won) Trade accounts and notes receivable ￦ 634,129 588,733 Other accounts receivable 187,706 160,729 Loans 258,957 147,980 Other assets 13,672 19,348 ￦ 1,094,464 916,790 ② 2017 2018 (in millions of Won) Bad debt expenses ￦ 173,694 74,781 Other bad debt expenses (*1) 100,920 81,353 Impairment loss on available-for-sale 123,214 — Less: Recovery of allowance for other bad debt accounts (2,743 ) (18,261 ) Less: Recovery of impairment loss on held-to-maturity (20 ) — ￦ 395,065 137,873 (*1) Other bad debt expenses are mainly related to loans and other accounts receivable. ③ 2017 2018 Trade accounts Allowance for Trade accounts Allowance for (in millions of Won) Not due ￦ 7,736,092 65,314 8,021,110 70,418 Overdue less than 1 month 445,390 12,546 632,082 14,434 1 month – 3 months 170,682 742 226,082 4,116 3 months – 12 months 384,313 21,030 118,094 11,774 Over 12 months 1,453,785 534,497 1,148,694 487,991 ￦ 10,190,262 634,129 10,146,062 588,733 ④ 2017 2018 Loans and Allowance for Loans and Allowance for (in millions of Won) Not due ￦ 1,888,726 9,672 1,754,293 140,072 Overdue less than 1 month 235,559 35,539 100,102 4,307 1 month – 3 months 69,372 54,335 28,351 851 3 months – 12 months 96,942 64,467 59,946 12,411 Over 12 months 365,202 296,322 230,746 170,416 ￦ 2,655,801 460,335 2,173,438 328,057 ⑤ 2016 2017 2018 (in millions of Won) Beginning ￦ 999,678 977,771 1,094,464 Initial application of IFRS No. 9 — — 107,454 Bad debt expenses 165,150 173,694 74,781 Other bad debt expenses 37,567 98,177 63,092 Others (*1) (224,624 ) (155,178 ) (423,001 ) Ending ￦ 977,771 1,094,464 916,790 (*1) Others for the year ended December 31, 2016, 2017 and 2018, included decreases mainly due to write-off ￦ ￦ ￦ (c) Liquidity risk 1) Contractual maturities for non-derivative Book value Contractual Within 1 year - After (in millions of Won) Trade accounts and notes payable ￦ 4,035,960 4,037,863 4,006,942 30,921 — Borrowings 20,209,270 24,319,619 12,912,399 10,452,389 954,831 Financial guarantee liabilities (*1) 68,205 3,147,280 3,147,280 — — Other financial liabilities 1,803,353 1,817,014 1,668,937 148,077 — ￦ 26,116,788 33,321,776 21,735,558 10,631,387 954,831 (*1) For issued financial guarantee contracts, the maximum amount of the guarantee is allocated to the earliest period in which the guarantee could be called. 2) Contractual maturities for derivative financial liabilities are as follows: Within 1 year 1 year - After Total (in millions of Won) Currency forward ￦ 11,364 34,743 — 46,107 Currency swap 1,707 5,849 4,369 11,925 Interest swap — 1,467 — 1,467 Others 14,258 — — 14,258 ￦ 27,329 42,059 4,369 73,757 (d) Currency risk 1) The Company has exposure to the risk that the fair value or future cash flows of a financial instrument will fluctuate because of the changes in foreign exchange rates. The exposure to currency risk as of December 31, 2017 and 2018 are as follows: 2017 2018 Assets Liabilities Assets Liabilities (in millions of Won) USD ￦ 4,215,151 5,940,380 4,346,481 6,389,276 EUR 552,630 454,072 657,690 509,437 JPY 165,356 709,318 97,722 389,625 Others 220,723 117,632 259,949 142,868 2) As of December 31, 2017 and 2018, provided that functional currency against foreign currencies other than functional currency hypothetically strengthens or weakens by 10%, the changes in gain or loss for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 10% increase 10% decrease 10% increase 10% decrease (in millions of Won) USD ￦ (172,523 ) 172,523 (204,280 ) 204,280 EUR 9,856 (9,856 ) 14,825 (14,825 ) JPY (54,396 ) 54,396 (29,190 ) 29,190 (e) Interest rate risk 1) The carrying amount of interest-bearing financial instruments as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Fixed rate Financial assets ￦ 10,943,300 11,565,519 Financial liabilities (11,179,635 ) (11,781,701 ) (236,335 ) (216,182 ) Variable rate Financial liabilities ￦ (9,977,040) (8,522,323 ) 2) Sensitivity analysis on the cash flows of financial instruments with variable interest rate The Company’s interest rate risk mainly arises from borrowings with variable interest rate. As of December 31, 2017 and 2018, provided that other factors remain the same and the interest rate of borrowings with floating rates increases or decreases by 1%, the changes in interest expense for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 1% increase 1% decrease 1% increase 1% decrease (in millions of Won) Variable rate financial instruments ￦ (99,770) 99,770 (85,223 ) 85,223

Share Capital and Capital Surpl

Share Capital and Capital Surplus	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Share Capital and Capital Surplus	24. Share Capital and Capital Surplus (a) Share capital as of December 31, 2017 and 2018 are as follows: 2017 2018 (Share, in Won) Authorized shares 200,000,000 200,000,000 Par value ￦ 5,000 5,000 Issued shares (*1) 87,186,835 87,186,835 Shared capital (*2) ￦ 482,403,125,000 482,403,125,000 (*1) As of December 31, 2018, total shares of ADRs of 36,860,288 outstanding in overseas stock market are equivalent to 9,215,072 of common stock. (*2) As of December 31, 2018, the difference between the ending balance of common stock and the par value of issued common stock is ￦ (b) The changes in issued common stock for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Issued Treasury Number of Issued Treasury Number of (share) Beginning 87,186,835 (7,189,170 ) 79,997,665 87,186,835 (7,187,231 ) 79,999,604 Disposal of treasury shares — 1,939 1,939 — 1,528 1,528 Ending 87,186,835 (7,187,231 ) 79,999,604 87,186,835 (7,185,703 ) 80,001,132 (c) Capital surplus as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Share premium ￦ 463,825 463,825 Gain on disposal of treasury shares 783,914 784,047 Other capital deficit 174,282 172,135 ￦ 1,422,021 1,420,007 (d) POSCO Energy Co., Ltd., a subsidiary of the Company, issued redeemable convertible preferred shares which are classified as non-controlling Redeemable Convertible Preferred Shares (Share, in Won) Issue date February 25, 2017 Number of shares issued 8,643,193 shares Price per share ￦ Voting rights No voting rights for 3 years from issue date Dividend rights Comparative, Non-participating Details about Redemption Issuer can demand redemption of all or part of redeemable convertible preferred shares every year after the issue date, for a period of 10 years from the issue date. Details about Conversion Stockholders of redeemable convertible preferred shares can convert them to common shares from 3 years after the issue date to the end of the redemption period (10 years). Redeemable convertible preferred stocks are classified as non-controlling

Hybrid Bonds

Hybrid Bonds	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Hybrid Bonds	25. Hybrid Bonds (a) Hybrid bonds classified as equity as of December 31, 2017 and 2018 are as follows: Date of Date of maturity Interest rate (%) 2017 2018 (in millions of Won) Hybrid bond 1-1 (*1) — — — ￦ 800,000 — Hybrid bond 1-2 (*2) 2013-06-13 2043-06-13 4.60 200,000 200,000 Issuance cost (3,081 ) (616 ) ￦ 996,919 199,384 (*1) During the year ended December 31, 2018, the Company exercised the call option of the Hybrid bond. (*2) Details of issuance of hybrid bonds as of December 31, 2018 are as follows: Hybrid bond 1-2 Maturity date 30 years (POSCO has a right to extend the maturity date) Interest rate Issue date ~ 2023-06-12 Step-up Interest payments condition Quarterly (Optional deferral of interest payment is available to POSCO) Others POSCO can call the hybrid bond at year 10 and interest payment date afterwards The hybrid bond holder’s preference in the event of liquidation is higher than the common stock holders, but lower than other creditors. The interest accumulated but not paid on the hybrid bonds as of December 31, 2018 amounts to ￦ (b) POSCO ENERGY CO., LTD., a subsidiary of the Company, issued hybrid bonds, which are classified as non-controlling Date of issue Date of maturity Interest rate (%) 2017 2018 (in millions of Won) Hybrid bond 1-1 (*1) — — — ￦ 165,000 — Hybrid bond 1-2 (*1) — — — 165,000 — Hybrid bond 1-3 (*1) — — — 30,000 — Hybrid bond 1-4 (*2) 2013-08-29 2043-08-29 5.21 140,000 140,000 Issuance cost (1,532 ) (429 ) ￦ 498,468 139,571 (*1) During the year ended December 31, 2018, the Company exercised the call option for the Hybrid bond. (*2) Details of issuance of hybrid bonds of POSCO ENERGY Co., Ltd .as of December 31, 2018 are as follows: Hybrid bond 1-4 Maturity date 30 years (The Company has a right to extend the maturity date) Interest rate Issue date ~ 2023-08-29 Step-up Interest payments condition Quarterly (Optional deferral of interest payment is available to the issuer) Others The issuer can call the hybrid bond at year 10 and interest payment date afterwards The hybrid bond holders’ preference in the event of liquidation is higher than the common stock holders, but lower than other creditors. The interest accumulated but not paid on the hybrid bonds as of December 31, 2018 amounts to ￦

Reserves

Reserves	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Reserves	26. Reserves (a) Reserves as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Accumulated comprehensive loss of investments in associates and joint ventures ￦ (516,528 ) (670,435 ) Changes in fair value of equity investments at fair value through other comprehensive income — (295,300 ) Changes in the unrealized fair value of available-for-sale 230,190 — Foreign currency translation differences (372,166 ) (417,817 ) Gain or losses on valuation of derivatives (136 ) (352 ) Others (23,916 ) (20,464 ) ￦ (682,556 ) (1,404,368 ) (b) Changes in unrealized fair value of available-for-sale 2017 2018 (in millions of Won) Beginning balance ￦ 276,143 230,190 Initial application of IFRS No. 9 — (421,525 ) Changes in unrealized fair value of equity investments 183,761 (139,226 ) Reclassification upon disposal (299,862 ) 45,737 Impairment of available-for-sale 96,083 — Others (25,935 ) (10,476 ) Ending balance ￦ 230,190 (295,300 )

Treasury Shares

Treasury Shares	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Treasury Shares	27. Treasury Shares Based on the Board of Directors’ resolution, POSCO holds treasury shares for business purposes including price stabilization. The changes in treasury shares for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Number of shares Amount Number of shares Amount (shares, in millions of Won) Beginning 7,189,170 ￦ 1,533,468 7,187,231 ￦ 1,533,054 Disposal of treasury shares (1,939 ) (414 ) (1,528 ) (326 ) Ending 7,187,231 ￦ 1,533,054 7,185,703 ￦ 1,532,728

Revenue

Revenue	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Revenue	28. Revenue (a) Disaggregation of revenue 1) Details of revenue disaggregated by types of revenue and timing of revenue recognition for the years ended December 31, 2016, 2017 and 2018 were as follows: ① For the year ended December 31, 2016 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 26,687,899 16,602,482 11,496 243,149 43,545,026 Revenue from services 102,657 24,703 50,189 2,237,129 2,414,678 Revenue from construction contract — — 6,474,192 23,087 6,497,279 Others 53,599 146,893 88,728 193,568 482,788 ￦ 26,844,155 16,774,078 6,624,605 2,696,933 52,939,771 Timing of revenue recognition Revenue recognized at a point in time ￦ 26,741,498 16,749,375 100,224 446,667 44,037,764 Revenue recognized over time 102,657 24,703 6,524,381 2,250,266 8,902,007 ￦ 26,844,155 16,774,078 6,624,605 2,696,933 52,939,771 ② For the year ended December 31, 2017 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 30,064,680 20,655,267 20,368 617,394 51,357,709 Revenue from services 111,494 28,793 48,408 1,876,179 2,064,874 Revenue from construction contract — — 6,262,038 37,154 6,299,192 Others 54,194 118,147 87,559 205,192 465,092 ￦ 30,230,368 20,802,207 6,418,373 2,735,919 60,186,867 Timing of revenue recognition Revenue recognized at a point in time ￦ 30,118,874 20,773,414 107,927 832,369 51,832,584 Revenue recognized over time 111,494 28,793 6,310,446 1,903,550 8,354,283 ￦ 30,230,368 20,802,207 6,418,373 2,735,919 60,186,867 ③ For the year ended December 31, 2018 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 31,733,609 21,632,183 3,568 605,206 53,974,566 Revenue from services 583,359 611,752 63,922 2,274,606 3,533,639 Revenue from construction contract — — 6,860,995 272,778 7,133,773 Others 41,041 163,782 17,784 290,051 512,658 ￦ 32,358,009 22,407,717 6,946,269 3,442,641 65,154,636 Timing of revenue recognition Revenue recognized at a point in time ￦ 31,774,650 21,795,965 127,182 906,120 54,603,917 Revenue recognized over time 583,359 611,752 6,819,087 2,536,521 10,550,719 ￦ 32,358,009 22,407,717 6,946,269 3,442,641 65,154,636 (b) Details of contract assets and liabilities from contracts with customers as of December 31, 2018 and January 1, 2018, the initial application date of IFRS No. 15 “Revenue from Contracts with Customers” and IFRS No. 9 “Financial Instruments”, are as follows; The date of initial 2018 (in millions of Won) Receivables Account receivables ￦ 8,795,470 8,819,617 Contract assets Due from customers for contract work 647,385 737,712 Contract liabilities Advance received 1,547,247 1,278,731 Due to customers for contract work 751,933 641,064 Unearned revenue 77,657 91,872

Revenue - Contract Balances

Revenue - Contract Balances	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Revenue - Contract Balances	29. Revenue – Contract Balances (a) Details of in-progress 2017 2018 (in millions of Won) Accumulated cost ￦ 21,404,321 26,153,452 Accumulated contract profit 1,524,208 1,848,718 Accumulated contract loss (718,593 ) (804,538 ) Accumulated contract revenue 22,209,936 27,197,632 (b) Details of due from customers for contract work and due to customers for contract work as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Unbilled due from customers for contract work ￦ 728,007 810,655 Due to customers for contract work (782,968 ) (641,064 ) ￦ (54,961 ) 169,591 (c) Due to the factors causing the variation of costs for the years ended December 31, 2017 and 2018, the estimated total contract costs have changed. Details of changes in estimated total contract costs and the impact on profit before income taxes for the years ended December 31, 2017, 2018 and future periods are as follows: 2017 2018 (in millions of Won) Changes in estimated total contract costs ￦ 164,812 427,812 Changes in profit before income taxes of construction contract : - Current period (69,656 ) (38,720 ) - Future periods (6,041 ) 69,428 The effect on the current and future profit is estimated based on the circumstances that have occurred from the commencement date of the contract to the end of period. The estimation is evaluated for the total contract costs and expected total contract revenue as of the end of the period. Also, it may change during future periods. (d) Uncertainty of estimates 1) Total contract revenues Total contract revenues are measured based on contractual amount initially agreed. However, the contract revenues can increase due to additional contract work, claims and incentive payments, or decrease due to penalty when the completion of contract is delayed due to the Company’s fault. Therefore, this measurement of contract revenues is affected by the uncertainty of the occurrence of future events. 2) Total contract costs Contract revenues are recognized based on the percentage of completion, which is measured on the basis of the gross cost amount incurred to date. Total contract costs are estimated based on estimates of future material costs, labor costs, outsourcing cost and others. There is uncertainty in estimates on future contract costs due to various internal and external factors such as fluctuation of market, the risk of business partner and the experience of project performance and others. The significant assumptions including uncertainty of the estimate of total contract costs are as follows: Method of significant assumption Material cost Assumption based on recent purchasing price and quoted market price Labor cost Assumption based on standard monthly and daily labor cost Outsourcing cost Assumption based on the past experience rate of similar project and market price Management reviews the assumptions used in estimated contract costs at each reporting period end and adjusts them, if necessary.

Selling and Administrative Expe

Selling and Administrative Expenses	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Selling and Administrative Expenses	30. Selling and Administrative Expenses (a) Other administrative expenses Other administrative expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Wages and salaries ￦ 769,589 774,900 813,467 Expenses related to post-employment benefits 200,956 78,654 73,290 Other employee benefits 176,794 159,920 176,240 Travel 40,828 39,790 40,929 Depreciation 103,442 97,261 101,274 Amortization 139,569 146,314 112,418 Communication 11,186 11,740 10,616 Electricity expenses 7,527 7,050 8,309 Taxes and public dues 78,895 72,826 71,973 Rental 82,005 69,976 69,516 Repairs 11,316 9,859 15,291 Entertainment 13,157 11,582 11,816 Advertising 86,141 119,724 106,875 Research & development 120,608 125,795 108,352 Service fees 201,129 193,387 165,938 Vehicles maintenance 10,090 8,211 8,942 Industry association fee 13,468 10,140 9,571 Conference 13,108 14,494 14,510 Increase to provisions 6,532 10,990 14,433 Others 40,050 40,493 51,995 ￦ 2,126,390 2,003,106 1,985,755 (b) Selling expenses Selling expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Freight and custody expenses (*1) ￦ 1,342,009 1,336,969 184,675 Operating expenses for distribution center 10,315 10,503 10,614 Sales commissions 94,377 115,925 79,080 Sales advertising 5,117 3,800 4,821 Sales promotion 10,670 12,414 13,792 Sample 2,335 1,989 2,716 Sales insurance premium 31,379 36,546 37,251 Contract cost 49,480 23,061 16,992 Others 8,004 16,070 19,304 ￦ 1,553,686 1,557,277 369,245 (*1) During the year ended December 31, 2018, the Company recognized the freight expenses included in selling expenses incurred for the delivery of transportation services identified as a separate performance obligations in cost of sales.

Research and Development Expend

Research and Development Expenditures Recognized as Expenses	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Research and Development Expenditures Recognized as Expenses	31. Research and Development Expenditures Recognized as Expenses Research and development expenditures recognized as expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Administrative expenses ￦ 120,608 125,795 108,352 Cost of sales 324,190 361,093 418,250 ￦ 444,798 486,888 526,602

Other Operating Income and Expe

Other Operating Income and Expenses	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Other Operating Income and Expenses	32. Other Operating Income and Expenses Details of other operating income and expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Other operating income Gain on disposals of assets held for sale ￦ 23,112 1,180 27,171 Gain on disposals of investment in subsidiaries, associates and joint ventures 23,305 81,794 45,241 Gain on disposals of property, plant and equipment 23,826 32,145 53,139 Gain on disposals of intangible assets 671 23,391 117,139 Gain on valuation of firm commitment — 56,301 39,028 Gain on insurance proceeds 22,400 5,878 14,034 Others (*1,2) 109,164 247,792 227,834 ￦ 202,478 448,481 523,586 Other operating expenses Impairment loss on assets held for sale ￦ (24,890 ) — (50,829 ) Loss on disposals of investments in subsidiaries, associates and joint ventures (22,499 ) (19,985 ) (5,226 ) Loss on disposals of property, plant and equipment (86,622 ) (151,343 ) (117,614 ) Impairment loss on property, plant and equipment (196,882 ) (117,231 ) (1,004,704 ) Impairment loss on investment property (318 ) — (51,461 ) Loss on disposals of investment property (21 ) (1,966 ) (9,154 ) Impairment loss on intangible assets (127,875 ) (167,995 ) (337,519 ) Increase to provisions (53,058 ) (33,964 ) (134,632 ) Loss on valuation of firm commitment — (43,164 ) (66,281 ) Donations (43,810 ) (51,424 ) (52,074 ) Idle tangible asset expenses (6,437 ) (10,490 ) (9,257 ) Others (*3) (143,083 ) (93,814 ) (175,711 ) ￦ (705,495 ) (691,376 ) (2,014,462 ) (*1) During the year ended December 31, 2018, the Controlling Company recognized ￦ (*2) The Company has recognized the refund of VAT and others amounting to ￦ (*3) During the year ended December 31, 2018, the Controlling Company recognized ￦

Finance Income and Costs

Finance Income and Costs	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Finance Income and Costs	33. Finance Income and Costs Details of finance income and costs for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Finance income Interest income (*1) ￦ 182,475 212,451 337,258 Dividend income 41,000 92,962 63,345 Gain on foreign currency transactions 1,032,552 785,616 716,060 Gain on foreign currency translations 377,723 564,016 212,443 Gain on derivatives transactions 316,524 210,727 247,513 Gain on valuations of derivatives 147,111 64,735 96,986 Gain on disposals of available-for-sale 130,830 425,684 — Gain on valuations of financial assets at fair value through profit or loss — — 16,149 Others 3,765 16,476 16,216 ￦ 2,231,980 2,372,667 1,705,970 Finance costs Interest expenses ￦ (658,726 ) (653,115 ) (741,296 ) Loss on foreign currency transactions (1,147,192 ) (756,654 ) (810,857 ) Loss on foreign currency translations (405,391 ) (422,880 ) (321,748 ) Loss on derivatives transactions (338,314 ) (236,273 ) (208,772 ) Loss on valuation of derivatives (162,676 ) (226,487 ) (40,674 ) Impairment loss on available-for-sale (248,404 ) (123,214 ) — Loss on valuations of financial assets at fair value through profit or loss — — (59,442 ) Others (53,487 ) (65,654 ) (61,627 ) ￦ (3,014,190 ) (2,484,277 ) (2,244,416 ) (*1) Interest income calculated using the effective interest method for the years ended December 31, 2016, 2017, and 2018 were ￦ ￦ ￦

Expenses by Nature

Expenses by Nature	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Expenses by Nature	34. Expenses by Nature Expenses that are recorded by nature as cost of sales, selling and administrative expenses, impairment loss on other receivables and other operating expenses in the statements of comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows (excluding finance costs and income tax expense): 2016 2017 2018 (in millions of Won) Raw material used, changes in inventories and others ￦ 30,177,732 35,584,184 38,884,690 Employee benefits expenses (*2) 3,444,276 3,357,861 3,639,192 Outsourced processing cost 7,678,055 7,074,948 7,462,656 Electricity expenses 1,018,429 933,045 949,435 Depreciation (*1) 2,835,843 2,887,646 2,911,048 Amortization 378,004 409,774 356,581 Freight and custody expenses 1,342,009 1,336,969 1,414,940 Sales commissions 94,377 115,925 79,080 Loss on disposal of property, plant and equipment 86,622 151,343 117,614 Impairment loss on property, plant and equipment 196,882 117,231 1,004,704 Impairment loss on goodwill and intangible assets 127,875 167,995 337,519 Donations 43,810 51,424 52,074 Other expenses 3,448,497 4,253,625 4,445,124 ￦ 50,872,411 56,441,970 61,654,657 (*1) Includes depreciation expense of investment property. (*2) The details of employee benefits expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Wages and salaries ￦ 3,016,488 3,105,364 3,372,831 Expenses related to post-employment benefits 427,788 252,497 266,361 ￦ 3,444,276 3,357,861 3,639,192

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Income Taxes	35. Income Taxes (a) Income tax expense for the years ended December 31, 2016, 2017 and 2018 was as follows: 2016 2017 2018 (in millions of Won) Current income taxes (*1) ￦ 699,269 864,143 1,577,581 Deferred income tax due to temporary differences (209,706 ) 300,037 (38,851 ) Items recorded directly in equity (110,019 ) 21,560 144,900 Income tax expense ￦ 379,544 1,185,740 1,683,630 (*1) Refund (additional payment) of income taxes when filing a final corporation tax return credited (charged) directly to current income taxes. (b) The income taxes credited (charged) directly to equity for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Net changes in fair value of equity investments at fair value through other comprehensive income ￦ (100,550 ) 1,271 47,423 Remeasurements of defined benefit plans (11,722 ) 22,208 56,289 Gain on sale of treasury shares (10 ) (40 ) (50 ) Others 2,263 (1,879 ) 41,238 ￦ (110,019 ) 21,560 144,900 (c) The following table reconciles the calculated income tax expense based on POSCO’s statutory rate (27.5%) to the actual amount of taxes recorded by the Company for the years ended December 31, 2016, 2017 and 2018. 2016 2017 2018 (in millions of Won) Profit before income tax expense ￦ 1,411,609 4,095,051 3,616,016 Income tax expense computed at statutory rate 341,148 990,540 982,287 Adjustments: Tax credits (30,124 ) (40,757 ) (32,103 ) Additional Income tax expense for prior years (11,829 ) (20,912 ) 44,336 Tax effect from tax audit — — 130,196 Investment in subsidiaries, associates and joint ventures 76,751 55,113 114,856 Tax effects due to permanent differences (9,962 ) 4,798 64,708 Effect of tax rate change (*1) — 175,647 — Others (*2) 13,560 21,311 379,350 38,396 195,200 701,343 Income tax expense ￦ 379,544 1,185,740 1,683,630 Effective tax rate (%) 26.89 % 28.96 % 46.56 % (*1) During the year ended December 31, 2017, the statutory rate changed from 24.2% to 27.5% for taxable income in excess of ￦ (*2) Includes the effect of undeductible impairment loss related to Synthetic Natural Gas (SNG) facility for the year ended December 31, 2018. (d) The movements in deferred tax assets (liabilities) for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Beginning Inc. (Dec.) Ending Beginning Inc. (Dec.) Ending (in millions of Won) Deferred income tax due to temporary differences Allowance for doubtful accounts (*1) ￦ 213,119 60,875 273,994 273,994 (92,851 ) 181,143 Reserve for technology developments (91,960 ) 53,973 (37,987 ) (37,987 ) 37,987 — PP&E — Depreciation (11,639 ) 26,280 14,641 14,641 (4,804 ) 9,837 Share of profit or loss of equity-accounted investees 70,259 125,783 196,042 196,042 31,552 227,594 Allowance for inventories valuation 15,651 (4,871 ) 10,780 10,780 (104 ) 10,676 PP&E — Revaluation (1,524,149 ) (304,015 ) (1,828,164 ) (1,828,164 ) (33,548 ) (1,861,712 ) Prepaid expenses 19,665 335 20,000 20,000 (2,741 ) 17,259 PP&E — Impairment loss 5,295 245 5,540 5,540 (927 ) 4,613 Gain or loss on foreign currency translation (5,957 ) (42,515 ) (48,472 ) (48,472 ) 10,462 (38,010 ) Defined benefit obligations 361,838 68,279 430,117 430,117 70,334 500,451 Plan assets (355,661 ) (41,960 ) (397,621 ) (397,621 ) (66,940 ) (464,561 ) Provision for construction losses 997 (556 ) 441 441 6,964 7,405 Provision for construction warranty 24,322 4,395 28,717 28,717 41,601 70,318 Accrued income (9,441 ) (3,474 ) (12,915 ) (12,915 ) (179 ) (13,094 ) Others (*1) 750,151 (55,834 ) 694,317 694,317 (233,026 ) 461,291 (537,510 ) (113,060 ) (650,570 ) (650,570 ) (236,220 ) (886,790 ) Deferred income taxes recognized directly to equity Net changes in fair value of equity investments at fair value through other comprehensive income (*1) (50,507 ) 1,271 (49,236 ) (49,236 ) 206,121 156,885 Others 51,832 20,329 72,161 72,161 58,111 130,272 1,325 21,600 22,925 22,925 264,232 287,157 Deferred tax from tax credit Tax credit carry-forward and others 307,335 (189,303 ) 118,032 118,032 (2,443 ) 115,589 Investments in subsidiaries, associates and joint ventures Investments in subsidiaries, associates and joint ventures 86,130 (17,704 ) 68,426 68,426 135,512 203,938 ￦ (142,720 ) (298,467 ) (441,187 ) (441,187 ) 161,081 (280,106 ) (*1) These changes includes the cumulative impact of initial application of IFRS No. 15 and IFRS No. 9. (e) Deferred tax assets and liabilities for the years ended December 31, 2017 and 2018 are as follows: 2017 2018 Assets Liabilities Net Assets Liabilities Net (in millions of Won) Deferred income tax due to temporary differences Allowance for doubtful accounts ￦ 273,994 — 273,994 181,143 — 181,143 Reserve for technology developments — (37,987 ) (37,987 ) — — — PP&E — Depreciation 59,912 (45,271 ) 14,641 55,354 (45,517 ) 9,837 Share of profit or loss of equity-accounted investees 236,637 (40,595 ) 196,042 278,466 (50,872 ) 227,594 Allowance for inventories valuation 10,780 — 10,780 10,676 — 10,676 PP&E — Revaluation — (1,828,164 ) (1,828,164 ) — (1,861,712 ) (1,861,712 ) Prepaid expenses 20,000 — 20,000 17,259 — 17,259 PP&E — Impairment loss 5,639 (99 ) 5,540 5,240 (627 ) 4,613 Gain or loss on foreign currency translation 113,760 (162,232 ) (48,472 ) 121,797 (159,807 ) (38,010 ) Defined benefit obligations 430,117 — 430,117 500,451 — 500,451 Plan assets — (397,621 ) (397,621 ) — (464,561 ) (464,561 ) Provision for construction losses 441 — 441 7,405 — 7,405 Provision for construction warranty 28,717 — 28,717 70,318 — 70,318 Accrued income — (12,915 ) (12,915 ) — (13,094 ) (13,094 ) Others 746,367 (52,050 ) 694,317 857,583 (396,292 ) 461,291 1,926,364 (2,576,934 ) (650,570 ) 2,105,692 (2,992,482 ) (886,790 ) Deferred income taxes recognized directly to equity Net changes in fair value of equity investments at fair value through other comprehensive income 110,865 (160,101 ) (49,236 ) 247,921 (91,036 ) 156,885 Others 92,981 (20,820 ) 72,161 153,609 (23,337 ) 130,272 203,846 (180,921 ) 22,925 401,530 (114,373 ) 287,157 Deferred tax from tax credit Tax credit carry-forward and others 118,032 — 118,032 115,589 — 115,589 Investments in subsidiaries, associates and joint ventures Investments in subsidiaries, associates and joint ventures 563,406 (494,980 ) 68,426 547,662 (343,724 ) 203,938 ￦ 2,811,648 (3,252,835 ) (441,187 ) 3,170,473 (3,450,579 ) (280,106 ) (f) As of December 31, 2018, the Company did not recognize income tax effects associated with deductible temporary differences of ￦ ￦

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Earnings per Share	36. Earnings per Share Basic and diluted earnings per share for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in Won, except per share information) Profit attribute to controlling interest ￦ 1,354,806,734,940 2,756,230,487,872 1,711,901,875,666 Interests of hybrid bonds (33,225,163,081 ) (33,048,799,997 ) (17,720,986,299 ) Weighted-average number of common shares outstanding (*1) 79,996,389 79,998,600 80,000,606 Basic and diluted earnings per share ￦ 16,521 34,040 21,177 (*1) The weighted-average number of common shares used to calculate basic and diluted earnings per share are as follows: 2016 2017 2018 (shares) Total number of common shares issued 87,186,835 87,186,835 87,186,835 Weighted-average number of treasury shares (7,190,446 ) (7,188,235 ) (7,186,229 ) Weighted-average number of common shares outstanding 79,996,389 79,998,600 80,000,606 Since there were no potential shares of common stock which had dilutive effects as of December 31, 2016, 2017 and 2018, diluted earnings per share is equal to basic earnings per share.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Related Party Transactions	37. Related Party Transactions (a) Significant transactions between the controlling company and related companies for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) For the year ended December 31, 2016 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 29,511 16,661 8 183,768 — 24,511 POSCO Processing & Service 1,212,220 5,778 549,803 2,896 22,704 2,445 POSCO COATED & COLOR STEEL Co., Ltd. 326,078 2,560 — — 12,232 126 POSCO ICT (*3) 1,224 727 — 219,301 32,456 171,107 eNtoB Corporation — 5 278,016 9,836 212 19,436 POSCO CHEMTECH 319,164 33,784 502,448 14,847 290,427 5,139 POSCO ENERGY CO., LTD. 187,311 1,382 — — — 7 POSCO TMC Co., Ltd. (*4) 219,489 — 2 — 863 1,177 POSCO AST (*4) 152,098 1 — — 19,695 922 POSCO DAEWOO Corporation 3,227,716 34,341 92,203 — 343 — POSCO Thainox Public Company Limited 237,471 2,915 9,593 — 19 548 POSCO America Corporation 469,543 — 284 — — 1,103 POSCO Canada Ltd. 275 — 148,528 — — — POSCO Asia Co., Ltd. 1,758,080 1,373 403,174 247 939 3,602 Qingdao Pohang Stainless Steel Co., Ltd. 135,405 — — — — 525 POSCO JAPAN Co., Ltd. 1,112,489 128 23,217 3,744 345 3,841 POSCO-VIETNAM Co., Ltd. 226,063 445 — — — — POSCO MEXICO S.A. DE C.V. 274,210 462 — — — — POSCO Maharashtra Steel Private Limited 355,829 2,613 — — — 93 POSCO(Suzhou) Automotive Processing Center Co., Ltd. 149,911 — — — — — Others 766,263 22,717 207,601 62,202 212,344 145,562 11,160,350 125,892 2,214,877 496,841 592,579 380,144 Associates and joint ventures SeAH Changwon Integrated Special Steel 28 — 1,095 — 627 — POSCO PLANTEC Co., Ltd. 2,245 48 3,533 244,898 16,812 8,146 SNNC 6,004 1,042 487,395 — — 2 POSCO-SAMSUNG-Slovakia Processing center 44,686 — — — — — KOBRASCO — 29,297 — — — — Others 26,625 13,122 175,246 — — — 79,588 43,509 667,269 244,898 17,439 8,148 ￦ 11,239,938 169,401 2,882,146 741,739 610,018 388,292 (*1) Sales and others mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System. (*4) During the year ended December 31, 2016, it was merged into POSCO Processing & Service. 2) For the year ended December 31, 2017 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 3,328 71 — 151,639 32 18,352 POSCO Processing & Service 298,781 1 113,628 4,595 8,309 404 POSCO COATED & COLOR STEEL Co., Ltd. 417,369 3,533 — — 8,483 106 POSCO ICT (*3) 1,697 5,097 — 315,748 29,773 183,226 eNtoB Corporation 1 30 330,921 8,215 139 26,023 POSCO CHEMTECH 359,862 33,076 479,896 23,043 296,296 6,860 POSCO ENERGY CO., LTD. 179,966 1,456 — — — 2 POSCO DAEWOO Corporation 5,214,127 35,182 550,258 221 44,108 1,948 POSCO Thainox Public Company Limited 218,005 9,780 10,168 — — — POSCO America Corporation 345,225 — 90 — — 1,776 POSCO Canada Ltd. 439 690 278,915 — — — POSCO Asia Co., Ltd. 1,949,354 1,454 365,025 337 1,625 4,982 Qingdao Pohang Stainless Steel Co., Ltd. 161,803 — — — — 176 POSCO JAPAN Co., Ltd. 1,436,159 20 26,256 621 — 44,829 POSCO-VIETNAM Co., Ltd. 212,883 — — — — 7 POSCO MEXICO S.A. DE C.V. 276,387 — — — — 1,749 POSCO Maharashtra Steel Private Limited 467,206 — — — — 65 POSCO (Suzhou) Automotive Processing Center Co., Ltd. 192,467 — — — — — Others 932,048 10,073 262,828 25,270 240,687 118,665 12,667,107 100,463 2,417,985 529,689 629,452 409,170 Associates and joint ventures POSCO PLANTEC Co., Ltd. 2,947 112 5,487 300,041 20,718 19,763 SNNC 6,734 712 554,151 — — 4 POSCO-SAMSUNG-Slovakia Processing Center 52,779 — — — — — Roy Hill Holdings Pty Ltd — — 697,096 — — — CSP — Compania Siderurgica do Pecem 7,384 — 159,501 — — — Others 14,943 52,583 79,103 — — 3 84,787 53,407 1,495,338 300,041 20,718 19,770 ￦ 12,751,894 153,870 3,913,323 829,730 650,170 428,940 (*1) Sales and others mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System 3) For the year ended December 31, 2018 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries (*3) POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 7,827 97 — 322,924 47 36,428 POSCO COATED & COLOR STEEL Co., Ltd. 476,105 2,725 — — 9,211 1,434 POSCO ICT (*4) 2,624 7,479 — 341,472 34,376 196,252 eNtoB Corporation 12 60 377,198 27,508 390 31,455 POSCO CHEMTECH 417,957 35,762 531,452 21,730 319,868 2,802 POSCO ENERGY CO., LTD. 206,638 1,445 — — — — POSCO DAEWOO Corporation 5,835,226 42,888 690,345 — 57,624 4,318 POSCO Thainox Public Company Limited 299,450 5,335 10,115 — — 71 POSCO America Corporation 336,366 — — — — 2,486 POSCO Canada Ltd. — 2,155 300,982 — — — POSCO Asia Co., Ltd. 1,857,665 253 536,280 650 2,449 6,524 Qingdao Pohang Stainless Steel Co., Ltd. 188,252 7 — — — 34 POSCO JAPAN Co., Ltd. 1,353,313 6 25,773 4,204 — 5,411 POSCO-VIETNAM Co., Ltd. 273,573 156 — — — 8 POSCO MEXICO S.A. DE C.V. 299,276 17 — — — 35 POSCO Maharashtra Steel Private Limited 563,618 584 — — — 156 POSCO (Suzhou) Automotive Processing Center Co., Ltd. 196,095 — 2,616 — — 5 Others (*5) 1,158,122 44,098 456,804 31,787 264,060 140,869 13,472,119 143,067 2,931,565 750,275 688,025 428,288 Associates and joint ventures (*3) POSCO PLANTEC Co., Ltd. 10,904 240 3,166 215,023 24,192 10,257 SNNC 5,105 4,108 558,425 — — 80 POSCO-SAMSUNG-Slovakia Processing Center 61,981 — — — — — Roy Hill Holdings Pty Ltd — — 810,196 — — — Others 14,199 54,747 64,335 — — 6 92,189 59,095 1,436,122 215,023 24,192 10,343 ￦ 13,564,308 202,162 4,367,687 965,298 712,217 438,631 (*1) Sales and others are mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others are mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) As of December 31, 2018, the Company provided guarantees to related parties (Note 38). (*4) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System. (*5) During the year ended December 31, 2018, the Company made loans of ￦ (b) The related account balances of significant transactions between the controlling company and related companies as of December 31, 2017 and 2018 are as follows: 1) December 31, 2017 Receivables Payables Trade accounts and Others Total Trade accounts and Accounts Others Total (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 2 2,908 2,910 — 21,965 674 22,639 POSCO COATED & COLOR STEEL Co., Ltd. 58,184 324 58,508 — 5 504 509 POSCO ICT 55 217 272 1,458 72,586 27,009 101,053 eNtoB Corporation — — — 12,252 31,899 20 44,171 POSCO CHEMTECH 61,810 3,589 65,399 51,774 20,313 17,568 89,655 POSCO ENERGY CO., LTD. 33,239 1,673 34,912 — — 1,425 1,425 POSCO DAEWOO Corporation 483,915 12,739 496,654 10,213 2,145 5,794 18,152 POSCO Thainox Public Company Limited 57,826 — 57,826 1,204 — — 1,204 POSCO America Corporation 5,365 — 5,365 — — — — POSCO Asia Co., Ltd. 404,857 541 405,398 9,811 24 — 9,835 Qingdao Pohang Stainless Steel Co., Ltd. 31,693 — 31,693 — — — — POSCO MEXICO S.A. DE C.V. 55,695 530 56,225 — — — — POSCO Maharashtra Steel Private Limited 392,630 5,733 398,363 — — — — Others 384,385 49,403 433,788 15,038 59,575 31,118 105,731 1,969,656 77,657 2,047,313 101,750 208,512 84,112 394,374 Associates and joint ventures POSCO PLANTEC Co., Ltd. 1,946 9 1,955 3,842 15,723 — 19,565 SNNC 648 61 709 49,506 3 — 49,509 Others 8,350 904 9,254 824 — — 824 10,944 974 11,918 54,172 15,726 — 69,898 ￦ 1,980,600 78,631 2,059,231 155,922 224,238 84,112 464,272 2) December 31, 2018 Receivables Payables Trade accounts and Others Total Trade accounts and Accounts Others Total (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 57 5,181 5,238 — 52,775 438 53,213 POSCO COATED & COLOR STEEL Co., Ltd. 55,598 317 55,915 — 25 1,194 1,219 POSCO ICT — 229 229 1,572 112,960 8,717 123,249 eNtoB Corporation — — — 10,860 22,072 11 32,943 POSCO CHEMTECH 40,258 3,883 44,141 19,911 58,725 19,012 97,648 POSCO ENERGY CO., LTD. 22,163 1,700 23,863 — — 1,425 1,425 POSCO DAEWOO Corporation 437,554 1,056 438,610 161 1,881 5,304 7,346 POSCO Thainox Public Company Limited 71,189 — 71,189 467 71 — 538 POSCO America Corporation 14,338 — 14,338 — 221 — 221 POSCO Asia Co., Ltd. 480,205 1,047 481,252 7,839 — — 7,839 Qingdao Pohang Stainless Steel Co., Ltd. 52,037 — 52,037 — — — — POSCO MEXICO S.A. DE C.V. 101,179 218 101,397 — — — — POSCO Maharashtra Steel Private Limited 390,413 1,428 391,841 — — — — Others 379,950 54,407 434,357 33,183 36,591 85,745 155,519 2,044,941 69,466 2,114,407 73,993 285,321 121,846 481,160 Associates and joint ventures POSCO PLANTEC Co., Ltd. 249 10 259 3,275 34,803 — 38,078 SNNC 541 61 602 22,188 — — 22,188 Roy Hill Holdings Pty Ltd — — — 22,997 — — 22,997 Others 918 910 1,828 217 76 — 293 1,708 981 2,689 48,677 34,879 — 83,556 ￦ 2,046,649 70,447 2,117,096 122,670 320,200 121,846 564,716 (c) Significant transactions between the Company, excluding the controlling company, and related companies for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) December 31, 2016 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures SeAH Changwon integrated Special Steel ￦ 16,294 — 22,029 — POSCO PLANTEC Co., Ltd. 21,659 5 3,335 5,912 New Songdo International City Development, LLC 226,042 — — 14 SNNC 29,330 — 21,479 9,494 Posco e&c Songdo International Building 4,245 — — 16,219 Chun-cheon Energy Co., Ltd 288,307 — — — Noeul Green Energy 107,268 — — — Incheon-Gimpo Expressway Co., Ltd. 102,183 — — — VSC POSCO Steel Corporation 43,650 47 479 — USS-POSCO 287,072 — 1,195 — CSP — Compania Siderurgica do Pecem 157,814 — — — Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 61,844 — 57,179 — LLP POSUK Titanium — — 14,575 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — — 24,365 — POS-SEAH 15,759 — — — PT. Batutua Tembaga Raya — — 13,079 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 31,711 — 65 — Zhangjiagang Pohang Refractories Co., Ltd. 250 14 364 2,472 Sebang Steel — — 26,276 — SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. 157,886 — 3,535 — DMSA/AMSA — — 72,582 — South-East Asia Gas Pipeline Company Ltd. — 87,973 — — Others 195,139 11,184 16,664 1,801 ￦ 1,746,453 99,223 277,201 35,912 2) December 31, 2017 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 19,513 — 98 8,113 New Songdo International City Development, LLC 223,567 13,207 — 49 SNNC 26,288 — 3,578 17,985 Chun-cheon Energy Co., Ltd 42,147 — — — Noeul Green Energy 11,863 — — 2,178 VSC POSCO Steel Corporation 19,404 — 188 — USS-POSCO 26,899 107 2,222 — CSP — Compania Siderurgica do Pecem 241,299 — 101,018 21,154 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 38,484 — 47,241 — LLP POSUK Titanium — — 3,972 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 4 — 20,145 — POS-SEAH 20,004 — — — PT. Batutua Tembaga Raya — — 21,024 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 34,088 — 192 — Zhangjiagang Pohang Refractories Co., Ltd. — — 87 1,632 Sebang Steel 441 — 23,778 — SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. 43,764 — — — DMSA/AMSA — 99 47,092 — South-East Asia Gas Pipeline Company Ltd. — 62,423 — — Others 272,107 43,126 19,520 19,483 ￦ 1,019,872 118,962 290,155 70,594 3) December 31, 2018 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 19,394 — 83 24,103 New Songdo International City Development, LLC 30,997 53,316 — 97 SNNC 66,075 128 2,395 71,421 Chun-cheon Energy Co., Ltd 25,693 — — — Noeul Green Energy 6,444 — — 587 VSC POSCO Steel Corporation 12,504 — 2,314 — USS-POSCO — — 2,595 — CSP — Compania Siderurgica do Pecem 239,922 9,678 346,602 26,324 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 46,538 — 62,851 — LLP POSUK Titanium — — 944 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — — 10,572 — POS-SEAH 12,244 — — — PT. Batutua Tembaga Raya — 168 15,663 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 30,417 — 249 — Sebang Steel — — 13,571 — DMSA/AMSA — — 46,293 — South-East Asia Gas Pipeline Company Ltd. — 50,789 — — Others 359,124 62,375 19,192 50,918 ￦ 849,352 176,454 523,324 173,450 (d) The related account balances of significant transactions between the Company, excluding the controlling company, and related companies as of December 31, 2017 and December 31, 2018 are as follows: 1) December 31, 2017 Receivables (*1) Payables Trade accounts and Loan Others Total Trade accounts and Others Total (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 2,287 — 5 2,292 3,442 5,595 9,037 New Songdo International City Development, LLC 484,038 282,775 1,696 768,509 — 7,146 7,146 Chun-cheon Energy Co., Ltd — — 21 21 — 9,617 9,617 Nickel Mining Company SAS — 59,668 118 59,786 — — — CSP — Compania Siderurgica do Pecem 380,180 — 13,443 393,623 — 29,700 29,700 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 2,108 5,357 6 7,471 2,449 — 2,449 PT. Batutua Tembaga Raya 24 29,048 — 29,072 — — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 8,067 5,357 32 13,456 107 — 107 DMSA/AMSA — 69,713 4,443 74,156 — — — South-East Asia Gas Pipeline Company Ltd. — 229,880 — 229,880 — — — Others 135,128 134,506 6,889 276,523 1,873 2,531 4,404 ￦ 1,011,832 816,304 26,653 1,854,789 7,871 54,589 62,460 (*1) As of December 31, 2017, the Company recognizes bad-debt ￦ 2) December 31, 2018 Receivables (*1) Payables Trade accounts and Loan Others Total Trade accounts and Others Total (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 3,593 — 6 3,599 6,160 217 6,377 New Songdo International City Development, LLC 233,157 — — 233,157 — — — Chun-cheon Energy Co., Ltd — — — — — 1,758 1,758 POSPower Co., Ltd 13,703 — — 13,703 — 66,856 66,856 Nickel Mining Company SAS — 59,664 118 59,782 — — — CSP — Compania Siderurgica do Pecem 364,190 — 9,669 373,859 62,578 — 62,578 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 10,836 — — 10,836 2,101 — 2,101 PT. Batutua Tembaga Raya — 35,100 171 35,271 — — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,274 3,354 27 9,655 66 — 66 DMSA/AMSA — 64,297 — 64,297 — — — South-East Asia Gas Pipeline Company Ltd. — 191,107 — 191,107 — — — Others 75,382 136,117 13,071 224,570 7,768 5,363 13,131 ￦ 707,135 489,639 23,062 1,219,836 78,673 74,194 152,867 (*1) As of December 31, 2018, the Company recognizes bad-debt ￦ (e) Significant financial transactions between the Company, excluding the controlling company, and related companies for the years ended December 31, 2017 and 2018 were as follows: 1) December 31, 2017 Beginning Lend Collect Others (*4) Ending (in millions of Won) Associates and joint ventures METAPOLIS Co., Ltd. (*1) ￦ 13,270 — — (13,270 ) — New Songdo International City Development, LLC — 484,644 (201,869 ) — 282,775 GALE International Korea, LLC — 2,000 — — 2,000 DMSA/AMSA (*2) 90,638 2,956 — (23,881 ) 69,713 South-East Asia Gas Pipeline Company Ltd. 276,605 28,967 (46,252 ) (29,440 ) 229,880 PT. Batutua Tembaga Raya 38,120 — — (9,072 ) 29,048 PT. Tanggamus Electric Power 3,606 — — (409 ) 3,197 PT. Wampu Electric Power 5,761 — — (654 ) 5,107 PT. POSMI Steel Indonesia 4,834 — — (548 ) 4,286 Nickel Mining Company SAS 60,425 — — (757 ) 59,668 AN KHANH NEW CITY DEVELOPMENT J.V CO., LTD. (*1) 60,425 — — (60,425 ) — Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 6,647 — (577 ) (713 ) 5,357 KRAKATAU POS-CHEM DONG-SUH 7,251 — — (823 ) 6,428 Hamparan Mulya 3,626 — (3,626 ) — — POS-SEAH 5,438 — (5,438 ) — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 8,460 — (2,262 ) (841 ) 5,357 POS-SeAH 7,251 — (1,142 ) 319 6,428 AMCI (WA) PTY LTD 91,775 4,327 — (4,041 ) 92,061 POS-AUSTEM (*3) — — — 5,357 5,357 POS-AUSTEM (*3) — — — 8,571 8,571 SAMHWAN VINA CO., LTD (*3) — — — 1,071 1,071 ￦ 684,132 522,894 (261,166 ) (129,556 ) 816,304 (*1) During the year ended December 31, 2017, it was excluded from associates. (*2) During the year ended December 31, 2017, loans amounting to ￦ (*3) During the year ended December 31, 2017, it was newly classified to associates and joint ventures. (*4) Includes adjustments of foreign currency translation differences and others. 2) December 31, 2018 Beginning Lend Collect Others (*2) Ending (in millions of Won) Associates and joint ventures New Songdo International City Development, LLC ￦ 282,775 150 (252,759 ) (30,166 ) — GALE International Korea, LLC 2,000 8,500 (10,500 ) — — UITrans LRT Co., Ltd. — 5,695 — — 5,695 DMSA/AMSA (*1) 69,713 9,965 (342 ) (15,039 ) 64,297 South-East Asia Gas Pipeline Company Ltd. 229,880 — (47,569 ) 8,796 191,107 PT. Batutua Tembaga Raya 29,048 4,678 — 1,374 35,100 PT. Tanggamus Electric Power 3,197 — — 1,226 4,423 PT. Wampu Electric Power 5,107 — — 223 5,330 PT. POSMI Steel Indonesia 4,286 — (2,200 ) 150 2,236 Nickel Mining Company SAS 59,668 — — (4 ) 59,664 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 5,357 — (5,357 ) — — KRAKATAU POS-CHEM DONG-SUH 6,428 — — 281 6,709 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 5,357 4,451 (6,454 ) — 3,354 POS-SeAH 6,428 — — 281 6,709 AMCI (WA) PTY LTD 92,061 3,795 — (5,376 ) 90,480 POS-AUSTEM 5,357 5,564 (5,357 ) 26 5,590 POS-AUSTEM 8,571 8,902 (8,571 ) 43 8,945 SAMHWAN VINA CO., LTD 1,071 — (1,071 ) — — ￦ 816,304 51,700 (340,180 ) (38,185 ) 489,639 (*1) During the year ended December 31, 2018, loans amounting to ￦ (*2) Includes adjustments of foreign currency translation differences and others. (f) For the years ended December 31, 2016, 2017 and 2018, details of compensation to key management officers were as follows: 2016 2017 2018 (in millions of Won) Short-term benefits ￦ 90,916 112,688 115,618 Long-term benefits 17,905 8,632 13,400 Retirement benefits 17,870 20,422 21,658 ￦ 126,691 141,742 150,676 Key management officers include directors (including non-standing

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Commitments and Contingencies	38. Commitments and Contingencies (a) Contingent liabilities Contingent liabilities may develop in a way not initially expected. Therefore, management continuously assesses contingent liabilities to determine whether an outflow of resources embodying economic benefits has become probable. If it becomes probable that an outflow of future economic benefits will be required for an item previously dealt with as a contingent liability, a provision is recognized in the consolidated financial statements of the period in which the change in probability occurs (except in the extremely rare circumstances where no reliable estimate can be made). Management makes estimates and assumptions that affect disclosures of commitments and contingencies. All estimates and assumptions are based on the evaluation of current circumstances and appraisals with the supports of internal specialists or external consultants. Management regularly analyzes current information about these matters and provides for probable contingent losses including the estimate of legal expense to resolve the matters. Internal and external lawyers are used for these assessments. In making the decision regarding the need for a provision, management considers whether the Company has an obligation as a result of a past event, whether it is probable that an outflow or cash or other resources embodying economic benefits will be required to settle the obligation and the ability to make a reliable estimate of the amount of the obligation. (b) Details of guarantees Contingent liabilities on outstanding guarantees and others provided by the Company as of December 31, 2018 are as follows. Guarantee limit Guarantee amount Guarantor Guarantee beneficiary Financial institution Foreign currency Won Foreign Won (in millions of Won) [The Company] POSCO POSCO Asia Co., Ltd. BOC and others USD 100,000,000 111,810 100,000,000 111,810 POSCO ASSAN TST STEEL INDUSTRY SMBC and others USD 146,527,500 163,832 131,874,750 147,449 POSCO COATED STEEL (THAILAND) CO., LTD. The Great & CO Co., Ltd. (SPC) THB 5,501,000,000 188,959 5,501,000,000 188,959 POSCO Maharashtra Steel Private Limited Export-Import Bank of Korea and others USD 506,853,000 566,712 168,397,800 188,285 POSCO MEXICO S.A. DE C.V. BOA and others USD 160,000,000 178,896 160,000,000 178,896 POSCO SS VINA Co., Ltd. Export-Import Bank of Korea and others USD 354,351,050 396,200 274,570,077 306,996 POSCO-VIETNAM Co., Ltd. SMBC and others USD 156,000,000 174,424 156,000,000 174,424 PT. KRAKATAU POSCO Export-Import Bank of Korea and others USD 1,350,300,000 1,509,770 1,097,236,405 1,226,821 POSCO DAEWOO Corporation Daewoo Global Development. Pte., Ltd Export-Import Bank of Korea and others USD 196,017,000 219,167 196,017,000 219,167 Daewoo Power PNG Ltd. Export-Import Bank of Korea USD 47,600,000 53,222 47,600,000 53,222 POSCO ASSAN TST STEEL INDUSTRY ING and others USD 14,652,750 16,383 14,652,750 16,383 POSCO DAEWOO INDIA PVT., LTD. Shinhan Bank and others USD 149,400,000 167,044 77,990,903 87,203 PT. Bio Inti Agrindo Export-Import Bank of Korea and others USD 125,125,000 139,902 125,125,000 139,902 KEB Hana Bank IDR 150,000,000,000 11,520 150,000,000,000 11,520 Golden Lace DAEWOO Company Limited Shinhan Bank USD 9,000,000 10,063 6,000,000 6,708 POSCO DAEWOO CHINA CO., LTD Mizuho USD 8,000,000 8,945 7,290,000 8,151 Songdo Posco family Housing SHINYOUNG SECURITIES CO., LTD. KRW 10,000 10,000 — — POSCO ENGINEERING & CONSTRUCTION CO., LTD. POSCO E&C Vietnam Co., Ltd. Export-Import Bank of Korea and others USD 47,000,000 52,551 47,000,000 52,551 HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd. Woori bank and others USD 148,000,000 165,479 142,000,000 158,770 POSCO Engineering and Construction India Private Limited Woori bank USD 2,100,000 2,348 2,100,000 2,348 KEB Hana Bank INR 104,000,000 1,663 9,000,000 144 PT. POSCO E&C INDONESIA POSCO Asia Co., Ltd. and others USD 10,900,000 12,187 10,900,000 12,187 Daewoo Global Development. Pte., Ltd SMBC and others USD 163,633,000 182,958 163,633,000 182,958 Songdo Posco family Housing SHINYOUNG SECURITIES CO., LTD. KRW 10,000 10,000 — — POSCO ICT PT.POSCO ICT INDONESIA POSCO Asia Co., Ltd. USD 1,500,000 1,677 1,500,000 1,677 POSCO CHEMTECH PT.Krakatau Posco Chemtech Calcination POSCO Asia Co., Ltd. USD 15,200,000 16,995 14,400,000 16,101 POSCO COATED & COLOR STEEL Co., Ltd. Myanmar POSCO C&C Company, Limited. POSCO Asia Co., Ltd. USD 13,986,947 15,639 13,986,947 15,639 POSCO ENERGY CO., LTD. PT. KRAKATAU POSCO ENERGY Export-Import Bank of Korea and others USD 193,900,000 216,800 121,231,918 135,549 POSCO Asia Co., Ltd. POSCO SINGAPORE LNG TRADING PTE. LTD. SMBC USD 40,000,000 44,724 40,000,000 44,724 [Associates and joint ventures] POSCO CSP — Compania Siderurgica do Pecem Export-Import Bank of Korea and others USD 420,000,000 469,602 392,956,955 439,365 BNDES BRL 464,060,000 133,686 462,554,370 133,253 LLP POSUK Titanium SMBC USD 15,000,000 16,772 15,000,000 16,772 Nickel Mining Company SAS SMBC EUR 46,000,000 58,841 46,000,000 58,841 POSCO DAEWOO Corporation GLOBAL KOMSCO Daewoo LLC ICBC USD 8,225,000 9,196 8,225,000 9,196 POSCO ENGINEERING & CONSTRUCTION CO., LTD. New Songdo International City Development, LLC Others KRW 440,000 440,000 432,000 432,000 UITrans LRT Co., Ltd. Kookmin Bank and others KRW 20,740 20,740 3,766 3,766 Chun-cheon Energy Co., Ltd Kookmin Bank and others KRW 11,600 11,600 941 941 Pohang E&E Co., Ltd Heungkuk Life Insurance Co., Ltd. KRW 6,500 6,500 — — JB CLARK HILLS Korea Investment & Securities Co., Ltd. KRW 40,000 40,000 30,000 30,000 POSCO ICT Incheon-Gimpo Expressway Co, Ltd. KDB Bank KRW 100,000 100,000 100,000 100,000 UITrans LRT Co., Ltd. Kookmin Bank KRW 76,000 76,000 76,000 76,000 POSCO CHEMTECH KRAKATAU POS-CHEM DONG-SUH KEB Hana Bank USD 1,140,000 1,274 791,667 885 POSCO(Suzhou) Automotive Processing Center Co., Ltd. POS-InfraAuto KDB Bank USD 780,000 872 780,000 872 [Others] POSCO DAEWOO Corporation Ambatovy Project Investments Ltd. and others Export-Import Bank of Korea USD 87,272,727 97,580 12,030,434 13,451 POSCO ENGINEERING & CONSTRUCTION CO., LTD. Ecocity CO., LTD and others Others KRW 1,524,314 1,524,314 545,893 545,893 POSCO ICT SMS Energy and others KEB Hana Bank and others KRW 78,791 78,791 60,519 60,519 Hyochun CO., LTD KYOBO SECURITIES CO., LTD. KRW 39,575 39,575 39,575 39,575 BTL Enterprise and others Kyobo Life Insurance Co., Ltd and others KRW 1,165,352 1,165,352 1,165,352 1,165,352 POSCO AUSTRALIA PTY LTD Department of Trade and Investment (NSW Government) and others Woori bank and others AUD 26,147,711 20,599 26,147,711 20,599 USD 4,492,463,974 5,023,024 3,549,290,606 3,968,462 KRW 3,522,872 3,522,872 2,454,046 2,454,046 IDR 150,000,000,000 11,520 150,000,000,000 11,520 INR 104,000,000 1,663 9,000,000 144 THB 5,501,000,000 188,959 5,501,000,000 188,959 EUR 46,000,000 58,841 46,000,000 58,841 AUD 26,147,711 20,599 26,147,711 20,599 BRL 464,060,000 133,686 462,554,370 133,253 (c) POSCO ENGINEERING & CONSTRUCTION CO., LTD. has provided the completion guarantees for Samsung C&T Corporation amounting to ￦ ￦ (d) Other commitments Details of other commitments of the Company as of December 31, 2018 are as follows: Company Description POSCO POSCO entered into long-term contracts to purchase iron ore, coal, nickel and others. The contracts of iron ore and coal generally have terms of more than three years and the contracts of nickel have terms of more than one year. These contracts provide for periodic price adjustments based on the market price. As of December 31, 2018, 100 million tons of iron ore and 14 million tons of coal remained to be purchased under such long-term contracts. POSCO entered into an agreement with Tangguh Liquefied Natural Gas (LNG) Consortium in Indonesia to purchase 550 thousand tons of LNG annually for 20 years commencing in August 2005. The purchase price is subject to change, based on changes of the monthly standard oil price (JCC) and with a price ceiling. POSCO entered into consecutive voyage charter (CVC) contract for the transportation of raw materials. As of December 31, 2018, there are 38 vessels under contract and the average remaining contract period is about 10 years. During the year ended December 31, 2018, the freight expenses related to the CVC contract is USD 668 million. As of December 31, 2018, POSCO entered into a commitment with KOREA ENERGY AGENCY for long- term foreign currency borrowings, which are limited up to the amount of USD 6.49 million. The borrowing is related to the exploration of gas hydrates in Western Fergana-Chinabad. The repayment of the borrowings depends on the success of the projects. POSCO is not liable for the repayment of full or part of the amount borrowed if the respective projects fail. POSCO has agreed to pay a certain portion of its profits under certain conditions, as defined by the borrowing agreements. As of December 31, 2018, the ending balance of the borrowing amounts to USD 1.02 million. POSCO has provided a supplemental funding agreement, as the largest shareholder, as requested from the creditors, including Norddeutsche Landesbank, for seamless funding to POSCO ENERGY Co., Ltd. under construction of new power plant. POSCO provides a supplementary fund of up to ￦ POSCO provides a supplementary funding for the purpose of promoting the Suncheon Bay PRT business of Suncheon Eco Trans Co., Ltd., a subsidiary of the Company, at the request of creditors. On November 2018, creditors sued the company for subrogation based on a supplemental funding agreement. POSCO recognized the provision based on the estimate of the amount and the possibility of any outflows of resources due to the litigation. POSCO ENGINEERING & CONSTRUCTION CO., LTD. As of December 31, 2018, POSCO ENGINEERING & CONSTRUCTION CO., LTD. has foreign currency guarantee of up to USD 2,517 million and uses USD 763 million with Woori Bank and others. POSCO ICT As of December 31, 2018, in relation to contract enforcement, POSCO ICT was provided with ￦ ￦ ￦ (e) Litigation in progress As of December 31, 2018, litigations in progress that POSCO and certain subsidiaries are defendants in legal actions arising from the normal course of business are as follows: Company Legal Claim amount Won Description (in millions of Won, in thousands of foreign currencies) POSCO 27 KRW 75,218 75,218 Lawsuit on claim for employee right and others (*1) POSCO DAEWOO Corporation 1 CAD 79,000 64,808 Lawsuit on claim for damages 3 INR 4,518,694 72,254 Lawsuit on claim for payment on guarantees and others (*1) 10 KRW 20,049 20,049 Litigation for confirmation of deposit bond and others 5 USD 28,763 32,160 Lawsuit on claim for damages and others 1 PKR 124,775 1,003 Lawsuit on claim for damages POSCO ENGINEERING & CONSTRUCTION., LTD. 120 KRW 442,812 442,812 Lawsuit on claim for damages and others (*1) POSCO ICT 1 BRL 10,182 2,933 Lawsuit on revocation of claim for damage 11 KRW 6,452 6,452 Lawsuit on claim for damages and others 1 USD 1,881 2,103 Lawsuit on claim for damages POSCO A&C 8 KRW 2,752 2,752 Lawsuit on claim for payment on construction and others POSCO ENERGY CO., LTD. 3 KRW 3,039 3,039 Lawsuit on claim for damages and others POSCO E&C CHINA CO., LTD. 3 CNY 44,446 7,234 Lawsuit over contract dispute and others POSCO COATED & COLOR STEEL Co., Ltd. 1 KRW 1,400 1,400 Lawsuit on claim for payment POSCO ENGINEERING 2 THB 509,191 17,491 Lawsuit on claim for payment on construction and others PT. KRAKATAU POSCO 1 IDR 211,407,872 16,236 Lawsuit on claim for payment on construction POSCO E&C Vietnam Co., Ltd. 1 USD 3,894 4,354 Lawsuit on claim for payment on construction POSCO-China Qingdao 2 CNY 6,774 1,103 Lawsuit over contract dispute and others POSCO-Malaysia SDN. BHD. 1 MYR — — Lawsuit on claim for infringement of right Pos-Sea 1 USD 12,051 13,474 Lawsuit over contract dispute POSCO INDIA HOLDINGS PRIVATE 1 INR 220,000 3,518 Lawsuit over contract dispute POSCO TNPC Otomotiv Celik 8 TRY 102 22 Lawsuit over industrial accidents and others POSCO India Steel Distribution Center Private Ltd. 1 INR 223,795 3,578 Lawsuit on claim for tax restitution POSCO(Dalian) 1 CNY 4,240 690 Lawsuit over contract dispute Brazil Sao Paulo Steel 3 BRL 4,671 1,346 Lawsuit on claim for labor and others POSCO ENGINEERING & 148 BRL 156,011 44,944 Lawsuit on claim for payment on construction and others POSCO ASSAN TST STEEL INDUSTRY 1 TRY 4,870 1,027 Lawsuit on compensation HONG KONG POSCO E&C 1 KRW 3,305 3,305 Lawsuit on claim for payment (*1) The Company made a reliable estimate in 122 lawsuits by considering the possibility and amount of outflow of resources and recognized ￦ For all the other lawsuits and claims, management does not believe the Company has any present obligations and therefore, the Company has not recognized any provisions as of December 31, 2018 for the matters.

Additional Information of Cash

Additional Information of Cash Flow Statements	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Additional Information of Cash Flow Statements	39. Additional Information of Cash Flow Statements (a) Changes in operating assets and liabilities for the years ended December 31, 2016, 2017 and 2018 were as follows: IFRS 2016 2017 2018 (in millions of Won) Trade accounts and notes receivable ￦ 63,075 17,806 Other receivables 191,591 113,740 (20,786 ) Inventories (889,998 ) (1,435,170 ) (1,451,009 ) Other current assets (287,377 ) 110,688 1,118 Other non-current 33,584 12,455 5,974 Trade accounts and notes payable 769,337 (607,999 ) 379,742 Other payables (179,174 ) (26,922 ) (111,893 ) Other current liabilities 2,490 338,273 (199,981 ) Provisions (124,884 ) (145,763 ) (116,790 ) Payments of severance benefits (278,278 ) (185,220 ) (189,165 ) Plan assets (138,854 ) 3,815 (245,214 ) Other non-current 223,574 (82,605 ) (175,528 ) ￦ (1,841,633 ) (2,105,726 ) (b) Changes in liabilities arising from financial activities for the year ended December 31, 2017 and 2018 were as follows: 1) December 31, 2017 Liabilities Derivatives that hedge Short-term Long-term Dividend Finance (in millions of Won) Beginning ￦ 14,725,271 7,770 114,409 (52,373 ) Changes from financing cash flows 558,083 (1,410,033 ) (931,232 ) (10,536 ) — Changes arising from obtaining or losing control of subsidiaries or other business (12,469 ) 3,299 — — — The effect of changes in foreign exchange rates (350,523 ) (435,170 ) — (10,855 ) — Changes in fair values — — — — 171,693 Other changes: Decrease in retained earnings — — 863,579 — — Decrease in non-controlling — — 67,096 — — Amortization of discount on debentures issued — 5,472 — — — Ending ￦ 12,888,839 7,213 93,018 119,320 2) December 31, 2018 Liabilities Derivatives Short-term Long-term Dividend Finance (in millions of Won) Beginning ￦ 12,888,839 7,213 93,018 119,320 Changes from financing cash flows (854,554 ) (373,862 ) (770,099 ) (14,955 ) (17,237 ) Changes arising from obtaining or losing (342 ) — — — — The effect of changes in foreign exchange rates 167,858 200,308 (5,573 ) (7,766 ) — Changes in fair values — — — — (58,666 ) Other changes: — Decrease in retained earnings — — 704,444 — — Decrease in non-controlling — — 72,688 — — Amortization of discount on debentures issued — 6,205 — — — Increase in finance lease assets — — — 24,457 — Ending ￦ 12,721,490 8,673 94,754 43,417

Operating Segments and Geograph

Operating Segments and Geographic Information	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Operating Segments and Geographic Information	40. Operating Segments and Geographic Information (a) The Company’s operating businesses are organized based on the nature of markets and customers. The Company has four reportable operating segments—steel, construction, trading and others. The steel segment includes production of steel products and revenue of such products. The construction segment includes planning, designing and construction of industrial plants, civil engineering projects and commercial and residential buildings, both in Korea and overseas. The trading segment consists of exporting and importing a wide range of steel products and raw materials that are both obtained from and supplied to POSCO, as well as between other suppliers and purchasers in Korea and overseas. Other segments include power generation, network and system integration and logistics. The policies of classification and measurement on operating segments were the same for all periods presented. (b) Information about reportable segments as of and for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) As of and for the year ended December 31, 2016 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 26,844,154 16,774,078 6,768,348 2,696,933 53,083,513 Internal revenues 16,062,016 9,646,026 713,703 2,379,945 28,801,690 Including inter segment revenue 8,992,783 5,296,847 557,526 2,285,128 17,132,284 Total revenues 42,906,170 26,420,104 7,482,051 5,076,878 81,885,203 Interest income 126,210 40,424 65,256 13,564 245,454 Interest expenses (459,345 ) (70,841 ) (102,292 ) (126,523 ) (759,001 ) Depreciation and amortization (2,788,535 ) (165,863 ) (57,719 ) (264,299 ) (3,276,416 ) Impairment loss on property, plant and equipment and others (99,165 ) (45,995 ) (9,426 ) (88,696 ) (243,282 ) Impairment loss on available-for-sale (225,225 ) (28,988 ) (35,331 ) (24,902 ) (314,446 ) Share of profit or loss of investment in associates and joint ventures (211,084 ) (53,586 ) (283,833 ) (6,369 ) (554,872 ) Income tax expense (495,874 ) (18,629 ) 107,520 (56,026 ) (463,009 ) Segment profit (loss) 1,511,383 53,244 (1,403,712 ) (25,889 ) 135,026 Segment assets 69,914,939 13,580,179 9,501,046 8,529,600 101,525,764 Investment in subsidiaries, associates and joint ventures 16,109,360 1,100,973 795,445 1,200,295 19,206,073 Acquisition of non-current 2,334,842 249,597 25,533 191,715 2,801,687 Segment liabilities 20,292,764 10,134,170 6,780,380 4,709,689 41,917,003 2) As of and for the year ended December 31, 2017 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 30,230,368 20,802,207 6,886,606 2,735,919 60,655,100 Internal revenues 17,381,010 14,075,996 398,924 2,548,674 34,404,604 Including inter segment revenue 12,004,614 8,043,643 329,215 2,446,029 22,823,501 Total revenues 47,611,378 34,878,203 7,285,530 5,284,593 95,059,704 Interest income 128,827 32,799 100,922 17,940 280,488 Interest expenses (422,357 ) (121,967 ) (112,983 ) (100,656 ) (757,963 ) Depreciation and amortization (2,856,133 ) (206,490 ) (42,123 ) (255,620 ) (3,360,366 ) Impairment loss on property, plant and equipment and others (149,840 ) (140,839 ) (37,476 ) (8,564 ) (336,719 ) Impairment loss on available-for-sale (95,261 ) — (18,637 ) (13,421 ) (127,319 ) Share of profit or loss of investment in associates and joint ventures 8,352 — (8,555 ) (1,518 ) (1,721 ) Income tax expense (977,853 ) (109,710 ) (109,961 ) (77,172 ) (1,274,696 ) Segment profit 2,790,855 112,661 24,545 232,700 3,160,761 Segment assets 70,017,816 14,139,098 8,609,753 8,776,090 101,542,757 Investment in subsidiaries, associates and joint ventures 16,116,654 1,134,798 668,392 1,193,895 19,113,739 Acquisition of non-current 2,033,184 286,185 99,190 251,665 2,670,224 Segment liabilities 19,057,249 10,386,294 5,744,693 4,620,902 39,809,138 3) As of and for the year ended December 31, 2018 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 32,358,009 22,407,717 6,769,410 3,442,641 64,977,777 Internal revenues 18,063,213 15,911,138 551,324 2,755,176 37,280,851 Including inter segment revenue 12,496,287 8,743,666 465,057 2,639,561 24,344,571 Total revenues 50,421,222 38,318,855 7,320,734 6,197,817 102,258,628 Interest income 199,016 36,437 115,019 23,454 373,926 Interest expenses (468,681 ) (189,165 ) (111,101 ) (94,613 ) (863,560 ) Depreciation and amortization (2,812,666 ) (210,493 ) (36,840 ) (265,416 ) (3,325,415 ) Impairment loss on property, plant and equipment and others (1,057,474 ) (86,085 ) (82,521 ) (117,280 ) (1,343,360 ) Share of profit or loss of investment in associates and joint ventures (733,879 ) (160,085 ) (155,371 ) — (1,049,335 ) Income tax expense (1,307,292 ) (52,914 ) (238,441 ) (65,611 ) (1,664,258 ) Segment profit 1,268,313 49,264 234 13,608 1,331,419 Segment assets 70,976,493 15,550,854 7,333,221 8,017,433 101,878,001 Investment in subsidiaries, associates and joint ventures 16,099,692 1,379,045 511,230 932,107 18,922,074 Acquisition of non-current 2,239,467 132,017 49,095 232,281 2,652,860 Segment liabilities 20,289,037 11,454,079 4,386,852 4,134,352 40,264,320 (c) Reconciliations of total segment revenues, profit or loss, assets and liabilities, and other significant items to their respective consolidated financial statement line items are as follows: 1) Revenues 2016 2017 2018 (in millions of Won) Total revenue for reportable segments ￦ 81,885,203 95,059,704 102,258,628 Elimination of inter-segment revenue (28,801,690 ) (34,404,604 ) (37,280,851 ) Basis difference (*2) (143,742 ) (468,233 ) 176,859 ￦ 52,939,771 60,186,867 65,154,636 2) Profit 2016 2017 2018 (in millions of Won) Total profit (loss) for reportable segments ￦ 135,026 3,160,761 1,331,419 Goodwill and corporate FV adjustments (123,110 ) (84,370 ) (77,756 ) Elimination of inter-segment profits 1,036,253 (102,922 ) 638,401 Income tax expense 384,685 1,206,223 1,670,757 Basis difference (*2) (21,245 ) (84,641 ) 53,195 Profit before income tax expense ￦ 1,411,609 4,095,051 3,616,016 3) Assets 2017 2018 (in millions of Won) Total assets for reportable segments (*1) ￦ 101,542,757 101,878,001 Equity-accounted investees (15,555,972 ) (15,272,243 ) Goodwill and corporate FV adjustments 3,368,333 2,722,115 Elimination of inter-segment assets (10,330,159 ) (11,079,608 ) Basis difference (*2) 760,670 528,726 ￦ 79,785,629 78,776,991 (*1) As segment assets and liabilities are determined based on separate financial statements, for subsidiaries which are in a different segment from that of its immediate parent company, their carrying amount in separate financial statements is eliminated upon consolidation. In addition, adjustments are made to adjust the amount of investment in associates and joint ventures from the amount reflected in segment assets to that determined using equity method in consolidated financial statements. 4) Liabilities 2017 2018 (in millions of Won) Total liabilities for reportable segments ￦ 39,809,138 40,264,320 Corporate FV adjustments 483,693 321,320 Elimination of inter-segment liabilities (8,731,880 ) (9,096,926 ) Basis difference (*2) 897,953 615,663 ￦ 32,458,904 32,104,377 5) Other significant items a) December 31, 2016 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 245,454 — (62,979 ) — 182,475 Interest expenses (759,001 ) (807 ) 101,082 — (658,726 ) Depreciation and amortization (3,276,416 ) (104,949 ) 167,518 — (3,213,847 ) Share of profit or loss of investment in associates (554,872 ) (38,732 ) 504,927 — (88,677 ) Income tax expense (463,009 ) 21,945 56,379 5,141 (379,544 ) Impairment loss on property, plant and equipment and others (243,282 ) — (125,657 ) — (368,939 ) Impairment loss on available-for-sale (314,446 ) — 66,042 — (248,404 ) ￦ (5,365,572 ) (122,543 ) 707,312 5,141 (4,775,662 ) b) December 31, 2017 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 280,488 — (68,037 ) — 212,451 Interest expenses (757,963 ) 1,304 103,544 — (653,115 ) Depreciation and amortization (3,360,366 ) (106,195 ) 169,141 — (3,297,420 ) Share of profit or loss of investment in associates (1,721 ) — 12,261 — 10,540 Income tax expense (1,274,696 ) 21,270 47,203 20,483 (1,185,740 ) Impairment loss on property, plant and equipment and others (336,719 ) (867 ) 34,619 — (302,967 ) Impairment loss on available-for-sale (127,319 ) — 4,105 — (123,214 ) ￦ (5,578,296 ) (84,488 ) 302,836 20,483 (5,339,465 ) c) December 31, 2018 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 373,926 — (36,668 ) — 337,258 Interest expenses (863,560 ) 1,035 121,229 — (741,296 ) Depreciation and amortization (3,325,415 ) (103,932 ) 161,718 — (3,267,629 ) Share of profit or loss of investment in associates (1,049,335 ) — 1,161,970 — 112,635 Income tax expense (1,664,258 ) 25,921 (32,420 ) (12,873 ) (1,683,630 ) Impairment loss on property, plant and equipment and others (1,343,360 ) (779 ) (107,258 ) — (1,451,397 ) ￦ (7,872,002 ) (77,755 ) 1,268,571 (12,873 ) (6,694,059 ) (*2) Basis difference is related to the difference in recognizing revenue and expenses in connection with development and sale of certain residential real estate between the report reviewed by the CEO and the consolidated financial statements. (d) Revenue by geographic area for the years ended December 31, 2016, 2017 and 2018 was as follows: 2016 2017 2018 (in millions of Won) Domestic ￦ 34,883,941 38,882,220 41,671,930 Japan 1,892,022 2,200,405 2,084,061 China 5,908,046 6,731,214 6,945,266 Indonesia 908,361 1,266,572 1,592,046 Asia-other 4,741,482 6,483,981 7,312,486 North America 1,899,291 1,725,120 1,834,534 Others 2,850,370 3,365,588 3,537,454 53,083,513 60,655,100 64,977,777 Basis difference (143,742 ) (468,233 ) 176,859 ￦ 52,939,771 60,186,867 65,154,636 In presenting information on the basis of geography, segment revenue is based on the geographical location of customers. (e) Non-current 2017 2018 (in millions of Won) Domestic ￦ 30,790,462 28,298,293 Japan 162,328 146,490 China 1,284,561 1,185,828 Indonesia 2,750,084 2,711,032 Asia-other 2,516,715 2,356,904 North America 277,249 173,914 Others 1,119,319 1,245,252 ￦ 38,900,718 36,117,713 Non-current (f) There are no customers whose revenue is 10% or more of the consolidated revenue.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Basis of consolidation	Basis of consolidation (a) Business combinations The Company accounts for business combinations using the acquisition method when control is transferred to the Company. The consideration transferred in the acquisition is generally measured at fair value, as are the identifiable net assets acquired. Any goodwill that arises is tested annually for impairment. Any gain on bargain purchase is recognized in profit or loss immediately. Transaction costs are expensed as incurred, except if related to the issue of debt or equity securities. The consideration transferred does not include amounts related to the settlement of pre-existing Any contingent consideration payable is measured at fair value at the acquisition date. If the contingent consideration is classified as equity, then it is not remeasured and settlement is accounted for within equity. Otherwise, subsequent changes in the fair value of the contingent consideration are recognized in profit or loss. If share-based payment awards (replacement awards) are required to be exchanged for awards held by the acquiree’s employees (acquiree’s awards), then all or a portion of the amount of the acquirer’s replacement awards is included in measuring the consideration transferred in the business combination. This determination is based on the market-based measure of the replacement awards compared with the market-based measure of the acquiree’s awards and the extent to which the replacement awards relate to pre-combination (b) Non-controlling Non-controlling (c) Subsidiaries Subsidiaries are entities controlled by the Company. The Company controls an entity when it is exposed to, or has rights to, variable returns from its involvement with the entity and has the ability to affect those returns through its power over the entity. The financial statements of subsidiaries are included in the consolidated financial statements from the date on which control commences until the date on which control ceases. (d) Loss of control When the Company loses control over a subsidiary, it derecognizes the assets and liabilities of the subsidiary, and any related non-controlling (e) Interests in equity-accounted investees The Company’s interests in equity-control investees comprise interests in associates and joint ventures. Associates are those entities in which the Company has significant influence, but not control or joint control, over the financial and operating policies. A joint venture is an arrangement in which the Company has joint control, whereby the Company has rights to the net assets of the arrangement, rather than rights to its assets and obligations for its liabilities. Interests in associates and joint ventures are accounted for using the equity method. They are recognized initially at cost, which includes transaction costs. Subsequent to initial recognition, the consolidated financial statements include the Company’s share of the profit or loss and other comprehensive income of equity-accounted investees, until the date on which significant influence or joint control ceases. (f) Transactions eliminated on consolidation Intra-group balances and transactions, and any unrealized income and expenses arising from intra-group transactions, are eliminated. Unrealized gains arising from transactions with equity-accounted investees are eliminated against the investment to the extent of the Company’s interest in the investee. Unrealized losses are eliminated in the same way as unrealized gains, but only to the extent that there is no evidence of impairment.
Foreign currency transactions and translation	Foreign currency transactions and translation (a) Foreign currency transactions Foreign currency transactions are initially recorded using the spot exchange rate between the functional currency and the foreign currency at the date of the transaction. At the end of each reporting period, foreign currency monetary items are translated using the closing rate. Non-monetary Non-monetary Exchange differences arising on the settlement of monetary items or on translating monetary items at rates different from those at which they were translated on initial recognition during the period or in previous financial statements are recognized in profit or loss in the period in which they arise. When gains or losses on non-monetary non-monetary (b) Foreign operations If the presentation currency of the Company is different from a foreign operation’s functional currency, the financial statements of the foreign operation are translated into the presentation currency using the following methods: The assets and liabilities of foreign operations, whose functional currency is not the currency of a hyperinflationary economy, are translated to presentation currency at exchange rates at the reporting date. The income and expenses of foreign operations are translated to functional currency at exchange rates at the dates of the transactions. Foreign currency differences are recognized in other comprehensive income. Any goodwill arising on the acquisition of a foreign operation and any fair value adjustments to the carrying amounts of assets and liabilities arising on the acquisition of that foreign operation are treated as assets and liabilities of the foreign operation. Thus, they are expressed in the functional currency of the foreign operation and translated at the closing rate. When a foreign operation is disposed of, the relevant amount in the translation is transferred to profit or loss as part of the profit or loss on disposal. On the partial disposal of a subsidiary that includes a foreign operation, the relevant proportion of such cumulative amount is reattributed to non-controlling Foreign exchange gains or losses arising from a monetary item receivable from or payable to a foreign operation, the settlement of which is neither planned nor likely to occur in the foreseeable future and which in substance is considered to form part of the net investment in the foreign operation, are recognized in other comprehensive income in the translation reserve.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents comprise cash on hand, demand deposits, and short-term investments in highly liquid securities that are readily convertible to known amounts of cash with maturities of three months or less from the acquisition date and which are subject to an insignificant risk of changes in value. Equity investments are excluded from cash and cash equivalents.
Non-derivative financial assets	Non-derivative Trade receivables and debt securities issued are initially recognized when they are originated. All other financial assets are initially recognized when the Company becomes a party to the contractual provisions of the instrument. A financial asset(unless it is a trade receivable without a significant financing component) is initially measured at fair value plus, for an item not at financial assets measured at fair value through profit or loss, transaction costs that are directly attributable to its acquisition or issue. A trade receivable without a significant financing component is initially measured at the transaction price. (a) Classification and subsequent measurement — Policies applicable from January 1, 2018 On initial recognition, a financial asset is classified as measured at amortized cost, debt instruments measured at fair value through other comprehensive income, equity instruments measured at fair value through other comprehensive income or financial assets measured at fair value through profit or loss. Financial assets are not reclassified subsequent to their initial recognition unless the Company changes its business model for managing financial assets, in which case all affected financial assets are reclassified on the first day of the first day of the first reporting period following the change in the business model. Financial assets measured at amortized cost A financial asset is measured at amortized cost if it meets both of the following conditions and is not designated as at fair value through profit or loss. • it is held within a business model whose objective is to hold assets to collect contractual cash flows, and • its contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. Financial assets measured at amortized cost are subsequently measured at amortized cost using the effective interest method. The amortized cost is reduced by impairment losses. Interest income, gains and losses on foreign currency translation and impairment losses are recognized in profit or loss. Any gain or loss on derecognition is recognized in profit or loss. Debt instruments measured at fair value through other comprehensive income A debt instrument is measured at fair value through other comprehensive income if it meets both of the following conditions and is not designated as at fair value through profit or loss. • it is held within a business model whose objective is achieved by both collection contractual cash flows and selling financial assets, and • its contractual terms give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. Debt instruments measured at fair value through other comprehensive income are subsequently measured at fair value. Interest income which is calculated using the effective interest method, gains and losses from foreign currency translation and impairment losses are recognized in profit or loss and other net profit or loss is recognized in other comprehensive income. At the time of elimination, other accumulated comprehensive income is reclassified to profit or loss. Equity instruments measured at fair value through other comprehensive income On initial recognition of an equity investment that is not held for trading, the Company may irrevocably elect to present subsequent changes in the investment’s fair value in other comprehensive income. This election is made on an investment-by-investment Equity instruments measured at fair value through other comprehensive income are subsequently measured at fair value. Dividends are recognized as income in profit or loss unless the dividend clearly represents a recovery of part of the cost of the investment. Other net gains and losses are recognized in other comprehensive income and never reclassified to profit or loss. Financial assets measured at fair value through profit or loss All financial assets not classified as measured at amortized cost of fair value through other comprehensive income as described above are measured at fair value through profit or loss. This includes all derivative financial assets. On initial recognition, the Company may irrevocably designate a financial asset that otherwise meets the requirements to be measured at amortized cost or at fair value through other comprehensive income as at fair value through profit or loss if doing so eliminates or significantly reduces an accounting mismatch that would otherwise arise. Financial assets measured at fair value through profit or loss are subsequently measured at fair value. Net gains and losses, including any interest or dividend income, are recognized in profit or loss. (b) Classification and subsequent measurement — Policies applied before January 1, 2018 The Company recognizes and measures non-derivative financial assets by the following four categories: financial assets at fair value through profit or loss, held-to-maturity financial assets, loans and receivables and available-for-sale financial assets. Financial assets at fair value through profit or loss Financial assets are classified at fair value through profit or loss if they are held for trading or designated as such upon initial recognition. Upon initial recognition, transaction costs are recognized in profit or loss when incurred. Financial assets at fair value through profit or loss are measured at fair value, and changes therein are recognized in profit or loss. Held-to-maturity financial assets A non-derivative financial asset with a fixed or determinable payment and fixed maturity, for which the Company has the positive intention and ability to hold to maturity, is classified as held-to-maturity. Subsequent to initial recognition, held-to-maturity financial assets are measured at amortized cost using the effective interest rate method. Loans and receivables Loans and receivables are non-derivative financial assets with fixed or determinable payments that are not quoted in an active market. Subsequent to initial recognition, loans and receivables are measured at amortized cost using the effective interest method unless the effect of discounting is immaterial. Available-for-sale financial assets Available-for-sale financial assets are those non-derivative financial assets that are designated as available-for-sale or are not classified as financial assets at fair value through profit or loss, held-to-maturity financial assets or loans and receivables. Subsequent to initial recognition, they are measured at fair value, with changes in fair value, net of any tax effect, recorded in other comprehensive income in equity. Investments in equity instruments that do not have a quoted market price in an active market and whose fair value cannot be reliably measured and derivatives that are linked to and must be settled by delivery of such unquoted equity instruments are measured at cost. When a financial asset is derecognized or impairment losses are recognized, the cumulative gain or loss previously recognized in other comprehensive income is reclassified from equity to profit or loss. Dividends on an available-for-sale equity instrument are recognized in profit or loss when the Company’s right to receive payment is established. (c) Derecognition of non-derivative The Company derecognizes non-derivative If the Company retains substantially all the risks and rewards of ownership of the transferred financial assets, the Company continues to recognize the transferred financial assets and recognizes financial liabilities for the consideration received. (d) Offsetting a financial asset and a financial liability Financial assets and financial liabilities are offset and the net amount is presented in the consolidated statement of financial position only when the Company currently has a legally enforceable right to offset the recognized amounts, and there is the intention to settle on a net basis or to realize the asset and settle the liability simultaneously.
Inventories	Inventories Inventory costs, except materials-in-transit Inventories are measured at the lower of cost or net realizable value. The amount of any write-down The carrying amount of those inventories is recognized as cost of goods sold in the period in which the related revenue is recognized.
Non-current assets held for sale	Non-current Non-current non-current The Company recognizes an impairment loss for any initial or subsequent write-down of an asset or disposal group to fair value less costs to sell, and a gain for any subsequent increase in fair value less costs to sell, up to the cumulative impairment loss previously recognized in accordance with IAS No. 36 “Impairment of Assets”. A non-current
Investment property	Investment property Property held to earn rentals or for capital appreciation or both is classified as investment property. Investment property is measured initially at its cost. Transaction costs are included in the initial measurement. Subsequently, investment property is carried at depreciated cost less any accumulated impairment losses. Subsequent costs are recognized in the carrying amount of investment property at cost or, if appropriate, as separate items if it is probable that future economic benefits associated with the item will flow to the Company and the cost of the item can be measured reliably. The carrying amount of the replaced part is derecognized. The costs of the day-to-day Depreciation methods, useful lives and residual values are reviewed at the end of each reporting date and adjusted, if appropriate. The change is accounted for as a change in an accounting estimate.
Property, plant and equipment	Property, plant and equipment Property, plant and equipment are initially measured at cost and after initial recognition, are carried at cost less accumulated depreciation and any accumulated impairment losses. The cost of property, plant and equipment includes expenditures arising directly from the construction or acquisition of the asset, any costs directly attributable to bringing the asset to the location and condition necessary for it to be capable of operating in the manner intended by management and, when the Company has an obligation to remove the asset or restore the site, an estimate of the costs of dismantling and removing the item and restoring the site on which it is located. The cost of replacing a part of an item is recognized in the carrying amount of the item of property, plant and equipment, if the following recognition criteria are met: (a) it is probable that future economic benefits associated with the item will flow to the Company, and (b) the cost can be measured reliably. The carrying amount of the replaced part is derecognized at the time the replacement part is recognized. The costs of the day-to-day Items of property, plant and equipment are depreciated from the date they are available for use or, in respect of self-constructed assets, from the date that the asset is completed and ready for use. Other than land, the costs of an asset less its estimated residual value are depreciated. Depreciation of property, plant and equipment is recognized in profit or loss on a straight-line basis, which most closely reflects the expected pattern of consumption of the future economic benefits embodied in the asset, over the estimated useful lives of each component of an item of property, plant and equipment. Land is not depreciated. Each part of an item of property, plant and equipment with a cost that is significant in relation to the total cost of the item is depreciated separately. The gain or loss arising from the derecognition of an item of property, plant and equipment is included in profit or loss when the item is derecognized. The estimated useful lives for the current and comparative periods are as follows: Buildings 5-50 Structures 4-50 Machinery and equipment 4-25 Vehicles 3-20 Tools 3-10 Furniture and fixtures 3-20 Lease assets 3-30 Bearer plants 20 years The estimated residual value, useful lives and the depreciation method are reviewed at least at the end of each reporting period and, if expectations differ from previous estimates, the changes are accounted for as changes in accounting estimates.
Borrowing costs	Borrowing costs The Company capitalizes borrowing costs directly attributable to the acquisition, construction or production of a qualifying asset as part of the cost of that asset. Other borrowing costs are recognized in expense as incurred. A qualifying asset is an asset that requires a substantial period of time to get ready for its intended use or sale. Financial assets and inventories that are manufactured or otherwise produced over a short period of time are not qualifying assets. Assets that are ready for their intended use or sale when acquired are not qualifying assets. To the extent that the Company borrows funds specifically for the purpose of obtaining a qualifying asset, the Company determines the amount of borrowing costs eligible for capitalization as the actual borrowing costs incurred on that borrowing during the period less any investment income on the temporary investment of those borrowings. The Company immediately recognizes other borrowing costs as an expense. To the extent that the Company borrows funds generally and uses them for the purpose of obtaining a qualifying asset, the Company shall determine the amount of borrowing costs eligible for capitalization by applying a capitalization rate to the expenditures on that asset. The capitalization rate shall be the weighted average of the borrowing costs applicable to the borrowings of the Company that are outstanding during the period, other than borrowings made specifically for the purpose of obtaining a qualifying asset. The amount of borrowing costs that the Company capitalizes during a period shall not exceed the amount of borrowing costs incurred during that period.
Intangible assets	Intangible assets Intangible assets are measured initially at cost and, subsequently, are carried at cost less accumulated amortization and accumulated impairment losses. Amortization of intangible assets except for goodwill is calculated on a straight-line basis over the estimated useful lives of intangible assets from the date that they are available for use. The residual value of intangible assets is zero. However, as there are no foreseeable limits to the periods over which club memberships are expected to be available for use, this intangible asset is determined as having an indefinite useful life and not amortized. Intellectual property rights 4-25 Development expense 3-5 Port facilities usage rights 4-75 Other intangible assets 2-15 Amortization periods and the amortization methods for intangible assets with finite useful lives are reviewed at the end of each reporting period. The useful lives of intangible assets that are not being amortized are reviewed at the end of each reporting period to determine whether events and circumstances continue to support indefinite useful life assessments for those assets. Changes are accounted for as changes in accounting estimates. Expenditures on research activities, undertaken with the prospect of gaining new scientific or technical knowledge and understanding, are recognized in profit or loss as incurred. Development expenditures are capitalized only if development costs can be measured reliably, the product or process is technically and commercially feasible, future economic benefits are probable, and the Company intends to and has sufficient resources to complete development and to use or sell the asset. Other development expenditures are recognized in profit or loss as incurred. Subsequent expenditures are capitalized only when they increase the future economic benefits embodied in the specific asset to which they relate. All other expenditures, including expenditures on internally generated goodwill and brands, are recognized in profit or loss as incurred.
Exploration for and evaluation of mineral resources	Exploration for and evaluation of mineral resources POSCO is engaged in exploration projects for mineral resources through subsidiaries, associates and joint ventures or other contractual arrangements. Expenditures related to the development of mineral resources are recognized as exploration or development intangible assets. The nature of these intangible assets are as follows: (a) Exploration and evaluation assets Exploration and evaluation assets consist of expenditures for topographical studies, geophysical studies and trenching. These assets are reclassified as development assets when it is proved that the exploration has identified commercially viable mineral deposit. (b) Development assets When proved reserves are determined and development is sanctioned, development expenditures incurred are capitalized. These expenditures include evaluation of oil fields, construction of oil/gas wells, drilling for viability and others. On completion of development and inception of extraction for commercial production of developed proved reserves, the development assets are reclassified as either property, plant and equipment or as intellectual property rights (mining rights) under intangible assets based on the nature of the capitalized expenditure. The respective property, plant and equipment and intellectual property (mining rights) are each depreciated and amortized based on proved reserves on a unit of production basis.
Government grants	Government grants Government grants are not recognized unless there is reasonable assurance that the Company will comply with the grant’s conditions and that the grant will be received. (a) Grants related to assets Government grants whose primary condition is that the Company purchase, construct or otherwise acquire long-term assets are deducted from the carrying amount of the assets and recognized in profit or loss on a systematic and rational basis over the life of the depreciable assets. (b) Grants related to income Government grants which are intended to compensate the Company for expenses incurred are deducted from the related expenses.
Leases	Leases The Company classifies and accounts for leases as either a finance or operating lease, depending on the terms. Leases where the Company assumes substantially all of the risks and rewards of ownership are classified as finance leases. All other leases are classified as operating leases. (a) Finance leases At the commencement of the lease term, the Company recognizes as finance assets and finance liabilities the lower amount of the fair value of the leased property and the present value of the minimum lease payments, each determined at the inception of the lease. Any initial direct costs are added to the amount recognized as an asset. Minimum lease payments are apportioned between the finance charge and the reduction of the outstanding liability. The finance charge is allocated to each period during the lease term so as to produce a constant periodic rate of interest on the remaining balance of the liability. Contingent rents are charged as expenses in the periods in which they are incurred. The depreciable amount of a leased asset is allocated to each accounting period during the period of expected use on a systematic basis consistent with the depreciation policy the Company adopts for similar depreciable assets that are owned. If there is no reasonable certainty that the Company will obtain ownership by the end of the lease term, the asset is fully depreciated over the shorter of the lease term and its useful life. (b) Operating leases Lease obligations under operating leases are recognized as an expense on a straight-line basis over the lease term. Contingent rents are charged as expenses in the periods in which they are incurred. (c) Determining whether an arrangement contains a lease Determining whether an arrangement is, or contains, a lease is based on the substance of the arrangement and requires an assessment of whether fulfillment of the arrangement is dependent on the use of a specific asset or assets (the asset) and the arrangement conveys a right to use the asset. At inception or reassessment of the arrangement, management of the Company separates payments and other consideration required by such an arrangement into those for the lease and those for other elements on the basis of their relative fair values. If management of the Company concludes for a financial lease that it is impracticable to separate the payments reliably, the Company recognizes an asset and a liability at an amount equal to the fair value of the underlying asset that was identified as the subject of the lease. Subsequently, the liability shall be reduced as payments are made and an imputed finance charge on the liability recognized using the purchaser’s incremental borrowing rate of interest.
Impairment for financial assets	Impairment for financial assets — Policies applicable from January 1, 2018 The Company recognizes loss allowances for expected credit losses on: • financial assets measured at amortized cost • debt instruments measured at fair value through other comprehensive income • lease receivables, contractual assets, loan commitments, and financial guarantee contracts If credit risk has increased significantly since the initial recognition, a loss allowance for lifetime expected credit loss is required to be measured at the end of every reporting period. If credit risk has not increased significantly since the initial recognition, a loss allowance is measured based on 12-month If the financial instrument has low credit risk at the end of the reporting period, the Company may assume that the credit risk has not increased significantly since initial recognition. However, a loss allowance for lifetime expected credit losses is required for contract assets or trade receivables that do not contain a significant financing component. (a) Judgments on credit risk When determining whether the credit risk of a financial asset has increased significantly since initial recognition and when estimating expected credit losses, the Company considers reasonable and supportable information that is relevant and available without undue cost or effort. This includes both quantitative and qualitative information and analysis, based on the Company’s historical experience and informed credit assessment and including forward-looking information. The Company assumes that the credit risk on a financial asset has increased significantly if it is more than 30 days past due. The Company considers a financial asset to be in default when the borrower is unlikely to pay its credit obligations to the Company in full, without recourse by the Company to actions such as realizing security (if any is held). The Company considers a debt security to have low credit risk when its credit risk rating is equivalent to the globally understood definition of investment grade. (b) Measurement of expected credit losses Lifetime expected credit losses are the expected credit losses that result from all possible default events over the expected life of a financial instrument. 12-month Expected credit losses are a probability-weighted estimate of credit losses. Credit losses are measured as the present value of all cash shortfalls such as the difference between the cash flows due to the entity in accordance with the contract and the cash flows that the Company expects to receive. Expected credit losses for financial assets measured at amortized cost are recognized in profit or loss. Loss allowances for financial assets measured at amortized cost are deducted from carrying amount of the assets. For debt instruments measured at fair value through other comprehensive income, the loss allowance is charged to profit or loss and is recognized in other comprehensive income. (c) Credit-impaired financial assets At each reporting date, the Company assesses whether financial assets measured at amortized cost and debt instrument measured at fair value through other comprehensive income are credit-impaired. A financial asset is ‘credit-impaired’ when one or more events that have a detrimental impact on the estimated future cash flows of the financial asset have occurred. Objective evidence that a financial asset or group of financial assets are impaired includes: • significant financial difficulty of the issuer or borrower • a breach of contract, such as a default or delinquency in interest or principal payments • the lender, for economic or legal reasons relating to the borrower’s financial difficulty, granting to the borrower a concession that the lender would not otherwise consider • it becoming probable that the borrower will enter bankruptcy or other financial reorganization • the disappearance of an active market for that financial asset because of financial difficulties (d) Write-off The gross carrying amount of a financial asset is written off when the Company has no reasonable expectations of recovering a financial asset in entirety or a portion. The Company individually makes an assessment with respect to the timing and amount of write-off Impairment for financial assets — Policies applied before January 1, 2018 A financial asset not carried at fair value through profit or loss is assessed at each reporting date to determine whether there is objective evidence that it is impaired. A financial asset is impaired if objective evidence indicates that a loss event has occurred after the initial recognition of the asset, and that the loss event had a negative effect on the estimated future cash flows of that asset that can be estimated reliably. However, losses expected as a result of future events, regardless of likelihood, are not recognized. Objective evidence that a financial asset or group of financial assets are impaired includes: (a) significant financial difficulty of the issuer or obligor; (b) a breach of contract, such as a default or delinquency in interest or principal payments; (c) the lender, for economic or legal reasons relating to the borrower’s financial difficulty, granting to the borrower a concession that the lender would not otherwise consider; (d) it becoming probable that the borrower will enter bankruptcy or other financial reorganization; (e) the disappearance of an active market for that financial asset because of financial difficulties; or (f) observable data indicating that there is a measurable decrease in the estimated future cash flows from a group of financial assets since the initial recognition of those assets, although the decrease cannot yet be identified with the individual financial assets in the group. In addition, for an investment in an equity security, a significant or prolonged decline in its fair value below its cost is objective evidence of impairment. If there is objective evidence that financial assets are impaired, impairment losses are measured and recognized. (a) Financial assets measured at amortized cost An impairment loss in respect of a financial asset measured at amortized cost is calculated as the difference between its carrying amount and the present value of its estimated future cash flows discounted at the asset’s original effective interest rate. If it is not practicable to obtain the instrument’s estimated future cash flows, impairment losses would be measured by using prices from any observable current market transactions. The Company can recognize impairment losses directly or establish a provision to cover impairment losses. If, in a subsequent period, the amount of the impairment loss decreases and the decrease can be related objectively to an event occurring after the impairment was recognized, the previously recognized impairment loss shall be reversed either directly or by adjusting an allowance account. (b) Financial assets carried at cost If there is objective evidence that an impairment loss has occurred on an unquoted equity instrument that is not carried at fair value because its fair value cannot be reliably measured, or on a derivative asset that is linked to and must be settled by delivery of such an unquoted equity instrument, the amount of the impairment loss is measured as the difference between the carrying amount of the financial asset and the present value of estimated future cash flows discounted at the current market rate of return for a similar financial asset. Such impairment losses are not reversed. (c) Available-for-sale financial assets When a decline in the fair value of an available-for-sale financial asset has been recognized in other comprehensive income and there is objective evidence that the asset is impaired, the cumulative loss that had been recognized in other comprehensive income shall be reclassified from equity to profit or loss as a reclassification adjustment even though the financial asset has not been derecognized. Impairment losses recognized in profit or loss for an investment in an equity instrument classified as available-for-sale are not reversed through profit or loss. If, in a subsequent period, the fair value of a debt instrument classified as available-for-sale increases and the increase can be objectively related to an event occurring after the impairment loss was recognized in profit or loss, the impairment loss shall be reversed, with the amount of the reversal recognized in profit or loss.
Impairment for non-financial assets	Impairment for non-financial The carrying amounts of the Company’s non-financial non-current Management estimates the recoverable amount of an individual asset. If it is impossible to measure the individual recoverable amount of an asset, then management estimates the recoverable amount of cash-generating unit (“CGU”). A CGU is the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. The Company determined that individual operating entities are CGUs. The recoverable amount of an asset or CGU is the greater of its value-in-use value-in-use pre-tax An impairment loss is recognized if the carrying amount of an asset or a CGU exceeds its recoverable amount. Impairment losses are recognized in profit or loss. Goodwill acquired in a business combination is allocated to each CGU that is expected to benefit from the synergies arising from the goodwill acquired. Any impairment identified at the CGU level will first reduce the carrying amount of goodwill and then be used to reduce the carrying amount of the other assets in the CGU on a pro rata basis. Except for impairment losses in respect of goodwill which are never reversed, an impairment loss is reversed if there has been a change in the estimates used to determine the recoverable amount. An impairment loss is reversed only to the extent that the asset’s carrying amount does not exceed the carrying amount that would have been determined, net of depreciation or amortization, if no impairment loss had been recognized.
Derivative financial instruments, including hedge accounting	Derivative financial instruments, including hedge accounting Derivatives are initially recognized at fair value. Subsequent to initial recognition, derivatives are measured at fair value, and changes therein are recognized as describe below. (a) Hedge accounting The Company holds forward exchange contracts, currency swaps and commodity future contracts to manage foreign exchange risk and commodity fair value risk. The Company designated derivatives as hedging instruments to hedge the risk of changes in the fair value of assets, liabilities or firm commitments (a fair value hedge) and foreign currency risk of highly probable forecasted transactions or firm commitments (a cash flow hedge). On initial designation of the hedge, the Company formally documents the relationship between the hedging instruments and hedged items, including the risk management objectives and strategy in undertaking the hedge transaction, together with the methods that will be used to assess the effectiveness of the hedging relationship. ① Fair value hedge Changes in the fair value of a derivative hedging instrument designated as a fair value hedge are recognized in profit or loss. The gain or loss from remeasuring the hedging instrument at fair value for a derivative hedging instrument and the gain or loss on the hedged item attributable to the hedged risk are recognized in profit or loss in the same line item of the consolidated statement of comprehensive income. The Company discontinues fair value hedge accounting if the hedging instrument expires or is sold, terminated or exercised, or if the hedge no longer meets the criteria for hedge accounting. Any adjustment arising from gain or loss on the hedged item attributable to the hedged risk is amortized to profit or loss from the date the hedge accounting is discontinued. ② Cash flow hedge When a derivative is designated to hedge the variability in cash flows attributable to a particular risk associated with a recognized asset or liability or a highly probable forecasted transaction that could affect profit or loss, the effective portion of changes in the fair value of the derivative is recognized in other comprehensive income, net of tax, and presented in the hedging reserve in equity. Any ineffective portion of changes in the fair value of the derivative is recognized immediately in profit or loss. If the hedging instrument no longer meets the criteria for hedge accounting, expires or is sold, terminated, exercised, or the designation is revoked, then hedge accounting is discontinued prospectively. The cumulative gain or loss on the hedging instrument that has been recognized in other comprehensive income is reclassified to profit or loss in the periods during which the forecasted transaction occurs. If the forecasted transaction is no longer expected to occur, then the balance in other comprehensive income is recognized immediately in profit or loss. (b) Other derivatives Changes in the fair value of a derivative that is not designated as a hedging instrument are recognized immediately in profit or loss.
Non-derivative financial liabilities	Non-derivative The Company classifies non-derivative (a) Financial liabilities measured at fair value through profit or loss A financial liability is classified as at fair value through profit or loss if it is classified as held-for-trading, (b) Financial liabilities measured at amortized cost Non-derivative (c) Derecognition of financial liabilities The Company derecognizes a financial liability when its contractual obligations are discharged or canceled, or expire. The Company also derecognizes a financial liability when its terms are modified and the cash flows of the modified liability are substantially different, in which case a new financial liability based on the modified terms is recognized at fair value. On derecognition of a financial liability, the difference between the carrying amount extinguished and the consideration paid (including any non-cash
Construction work in progress	Construction work in progress The gross amount due from customers for contract work is presented for all contracts in which profits multiply cumulative percentage-of-completion percentage-of-completion, The Company accounts for the remaining rights and performance obligation on the contract with the customers on a net basis. Due from customers for contract work and due to customers for contract work for same contract are offset and presented on a net basis.
Employee benefits	Employee benefits (a) Short-term employee benefits Short-term employee benefits are employee benefits that are due to be settled within twelve months after the end of the period in which the employees render the related service. When an employee has rendered service to the Company during an accounting period, the Company recognizes the undiscounted amount of short-term employee benefits expected to be paid in exchange for that service as profit or loss. If the Company has a legal or constructive obligation which can be reliably measured, the Company recognizes the amount of expected payment for profit-sharing and bonuses payable as liabilities. (b) Other long-term employee benefits Other long-term employee benefits include employee benefits that are settled beyond twelve months after the end of the period in which the employees render the related service, and are calculated at the present value of the amount of future benefit that employees have earned in return for their service in the current and prior periods, less the fair value of any related assets. Any actuarial gains and losses are recognized in profit or loss in the period in which they arise. (c) Retirement benefits: Defined contribution plans For defined contribution plans, when an employee has rendered service to the Company during a period, the Company recognizes the contribution payable to a defined contribution plan in exchange for that service as an accrued expense, after deducting any contributions already paid. If the contributions already paid exceed the contribution due for service before the end of the reporting period, the Company recognizes that excess as an asset (prepaid expense) to the extent that the prepayment will lead to a reduction in future payments or a cash refund. (d) Retirement benefits: Defined benefit plans A defined benefit plan is a post-employment benefit plan other than a defined contribution plan. The Company’s net obligation in respect of defined benefit plans is calculated by estimating the amount of future benefit that employees have earned in return for their service in the current and prior periods; that benefit is discounted to determine its present value. The fair value of plan assets is deducted. The calculation is performed annually by an independent actuary using the projected unit credit method. The discount rate is the yield at the reporting date on corporate bonds that have maturity dates approximating the terms of the Company’s obligations and that are denominated in the same currency in which the benefits are expected to be paid. The Company recognizes all actuarial gains and losses arising from actuarial assumption changes and experiential adjustments in other comprehensive income when incurred. When the fair value of plan assets exceeds the present value of the defined benefit obligation, the Company recognizes an asset, to the extent of the present value of the total of cumulative any economic benefits available in the form of refunds from the plan or reduction in the future contributions to the plan. Remeasurements of net defined benefit liabilities, which comprise actuarial gains and losses, the return on plan assets (excluding interest) and the effect of the asset ceiling (if any, excluding interest), are recognized immediately in other comprehensive income. The Company determines the net interest expense (income) on the net defined benefit liability (asset) for the period by applying the discount rate used to measure the defined benefit obligation at the beginning of the annual period to the then-net When the benefits of a plan are changed or when a plan is curtailed, the resulting change in benefit that relates to past service or the gain or loss in curtailment is recognized immediately in profit or loss. The Company recognizes gains and losses on the settlement of a defined benefit plan when the settlement occurs.
Provisions	Provisions Provisions are recognized when the Company has a present legal or constructive obligation as a result of a past event, it is probable that an outflow of resources embodying economic benefits will be required to settle the obligation and a reliable estimate can be made of the amount of the obligation. The risks and uncertainties that inevitably surround many events and circumstances are taken into account in reaching the best estimate of a provision. Where the effect of the time value of money is material, provisions are determined at the present value of the expected future cash flows. Where some or all of the expenditures required to settle a provision are expected to be reimbursed by another party, the reimbursement shall be recognized when, and only when, it is virtually certain that reimbursement will be received if the entity settles the obligation. The reimbursement shall be treated as a separate asset. Provisions are reviewed at the end of each reporting period and adjusted to reflect the current best estimates. If it is no longer probable that an outflow of resources embodying economic benefits will be required to settle the obligation, the provision is reversed. A provision for warranties is recognized when the underlying products are sold. The provision is based on historical warranty. Regarding provision for construction warranties, warranty period starts from the completion of construction in accordance with construction contracts. If the Company has an obligation for warranties, provision for warranties which are estimated based on historical warranty data are recorded as cost of construction and provision for warranties during the construction period. If the estimated total contract cost of the construction contract exceeds the total contract revenue, the estimated contract cost exceeding the contract revenue is recognized as a provision for construction losses in the remaining contract for which construction has not proceeded. A provision for restoration regarding contamination of land is recognized in accordance with the Company’s announced Environment Policy and legal requirement as needed. A provision is used only for expenditures for which the provision was originally recognized.
Emission Rights	Emission Rights The Company accounts for greenhouse gases emission right and the relevant liability as follows pursuant to the Act on Allocation and Trading of Greenhouse Gas Emission (a) Greenhouse gasses Emission Right Greenhouse gasses Emission Right consists of emission allowances which are allocated from the government free of charge and those purchased from the market. The cost includes any directly attributable costs incurred during the normal course of business. Emission rights held for the purpose of performing the obligation are classified as intangible asset and initially measured at cost and subsequently carried at cost less accumulated impairment losses. Emission rights held for short-swing profits are classified as current asset and are measured at fair value with any changes in fair value recognized as profit or loss in the respective reporting period. The Company derecognizes an emission right asset when the emission allowance is unusable, disposed or submitted to government when the future economic benefits are no longer expected to be probable. (b) Emission liability Emission liability is a present obligation of submitting emission rights to the government with regard to emission of greenhouse gas. Emission liability is recognized when there is a high possibility of outflows of resources in performing the obligation and the costs required to perform the obligation are reliably estimable. Emission liability is an amount of estimated obligations for emission rights to be submitted to the government for the performing period. The emission liability is measured based on the expected quantity of emission for the performing period in excess of emission allowance in possession and the unit price for such emission rights in the market at the end of the reporting period.
Equity instruments	Equity instruments (a) Share capital Common stock is classified as equity and the incremental costs arising directly attributable to the issuance of common stock less their tax effects are deducted from equity. If the Company reacquires its own equity instruments, the amount of those instruments (“treasury shares”) are presented as a contra equity account. No gain or loss is recognized in profit or loss on the purchase, sale, issuance or cancelation of its own equity instruments. When treasury shares are sold or reissued subsequently, the amount received is recognized as an increase to equity, and the resulting surplus or deficit on the transaction is recorded in capital surplus. (b) Hybrid Bonds Debt and equity instruments issued by the Company are classified as either financial liabilities or as equity in accordance with the substance of the contractual arrangements and the definitions of financial liability and an equity instrument. When the Company has an unconditional right to avoid delivering cash or another financial asset to settle a contractual obligation, the instruments are classified as equity instruments.
Revenue from contracts with customers	Revenue from contracts with customers The Company has initially applied IFRS No. 15 “Revenue from Contracts with Customers” from January 1, 2018. Revenue is measured based on the consideration promised in the contract with the customer. The Company recognizes revenue when the control over a good or service is transferred to the customer. The following are the revenue recognition policies for performance obligations in the contracts with customers. (a) Sale of good The goods sold by the Company consist mainly of steel products from the steel segment and products such as steel, chemicals, auto parts and machinery in the trade segment. For domestic sales, the control of the product is usually transferred to the customer when the product is delivered to the customer, at which point in time revenue is recognized. Invoices are generally payable within 10 to 90 days. When a customer makes payment prior to the due date, they are offered a discount at certain percentage of the invoice amount. For export sales, revenue is recognized at the time when control of the product is transferred to the customer based on the “International Incoterms for Interpretation of Trade Terms” prescribed in the respective contracts, which is generally when the products are loaded to the transportation vessels. Invoices are usually issued at the date of bill of lading and payments are settled by the terms of Letter of Credit (L / C), Document against Acceptance (D / A), Document against Payment (D / P), Telegraphic Transfer (T / T) and others. The Company provides certain discount when the customer prepays according to the payment terms. The Company recognized revenue only to the extent that it is highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur when discount period expire. (b) Transportation service For the performance obligation for transportation services included in the Company’s product sales contracts, revenue is recognized over the period when in which the services are provided and the revenue is measured by reference to examining the degree to which the service has been completed so far. The billing date and payment terms for the service charge are the same as the billing date and payment terms for sale of goods. (c) Construction contracts In the case of construction contracts where the Company renders construction services for plants, etc., the customer controls the assets as they are being constructed. This is because under those contracts, the Company is able to perform construction or design services to meet the customer’s specifications, and if a contract is terminated by the customer, the Company is entitled to reimbursement of all costs incurred to date, including a reasonable margin. When the contract can be reliably estimated, the company recognizes the contract revenue and contract cost as revenue and costs based on the progress of the contract activity as of the end of the reporting period. The percentage of completion is determined based on the proportion that contract costs incurred for work performed excluding contract cost incurred that do not reflect the stage of completion to date bear to the estimated total contract costs. If the outcome of the contract cannot be reliably estimated, the revenue is recognized only to the extent of the contract costs that are probable to be recovered. If the total contract cost is likely to exceed the total contract revenue, expected losses are immediately recognized as a cost. The Company issues an invoice when the customer has completed a progress confirmation and generally the payment is made within 45 days from the invoice date. (d) Certain construction contracts for apartments For certain construction service contracts for apartments where the criterion of an enforceable right to payment for performance is met under IFRS No. 15, even if the legal ownership or physical occupancy of the incomplete construction is not transferred to the customer during the construction period, revenue is recognized based on percentage of completion by considering the terms and conditions described in the relevant law and contracts such as the guarantee for sale policy, government approval on business plan, payment and termination terms. For certain construction contracts for apartments and shopping centers where the criterion of an enforceable right to payment for performance is not met during the construction period, the Company recognizes revenue upon completion of construction when the control of the apartments and shopping centers are transferred to customers. The timing of the billing and the payment terms of the sales contracts are different according to the terms of the contracts.
Finance income and finance costs	Finance income and finance costs The Company’s finance income and finance costs include: • interest income; • interest expense; • dividend income; • the foreign currency gain or loss on financial assets and financial liabilities; • the net gain or loss on financial assets measured at fair value through profit or loss; • hedge ineffectiveness recognized in profit or loss; and • the net gain or loss on the disposal of investments in debt securities measured at fair value through other comprehensive income. Interest income or expense is recognized using the effective interest method. Dividend income is recognized in profit or loss on the date on which the Company’s right to receive payment is established. The ‘effective interest rate’ is the rate that exactly discounts estimated future cash payments or receipts through the expected life of the financial instrument to: • the gross carrying amount of the financial asset; or • the amortized cost of the financial liability. In calculating interest income and expense, the effective interest rate is applied to the gross carrying amount of the asset (when the asset is not credit-impaired) or to the amortized cost of the liability. However, for financial assets that have become credit-impaired subsequent to initial recognition, interest income is calculated by applying the effective interest rate to the amortized cost of the financial asset. If the asset is no longer credit-impaired, then the calculation of interest income reverts to the gross basis.
Income taxes	Income taxes Income tax expense comprises current and deferred tax. Current tax and deferred tax are recognized in profit or loss except to the extent that it relates to a business combination, or items recognized directly in equity or in other comprehensive income. The Company recognizes interest and penalties related to corporate tax as if it is applicable to the income taxes, the Company applies IAS No. 12 “Income Taxes”, if it is not applicable to the income taxes, the Company applies IAS No. 37 “Provisions Contingent Liabilities and Contingent Assets”. (a) Current income tax Current income tax is the expected income tax payable or receivable on the taxable profit or loss for the year, using tax rates enacted or substantively enacted at the end of the reporting period and any adjustment to tax payable in respect of previous years. The taxable profit is different from the accounting profit for the period since the taxable profit is calculated excluding the temporary differences, which will be taxable or deductible in determining taxable profit of future periods, and non-taxable non-deductible The Company offsets current tax assets and current tax liabilities if, and only if, the Company: • has a legally enforceable right to set off the recognized amounts, and • intends either to settle on a net basis, or to realize the asset and settle the liability simultaneously. (b) Deferred income tax The measurement of deferred income tax liabilities and deferred tax assets reflects the tax consequences that would follow from the manner in which the Company expects, at the end of the reporting period, to recover or settle the carrying amount of its assets and liabilities. The Company recognizes a deferred income tax liability for all taxable temporary differences associated with investments in subsidiaries, associates, and joint ventures, except to the extent that the Company is able to control the timing of the reversal of the temporary difference and it is probable that the temporary difference will not reverse in the foreseeable future. The Company recognizes a deferred income tax asset for deductible temporary differences arising from investments in subsidiaries, associates and joint ventures, to the extent that it is probable that the temporary difference will reverse in the foreseeable future and taxable profit will be available against which the temporary difference can be utilized. However, deferred tax is not recognized for the following temporary differences: taxable temporary differences arising on the initial recognition of goodwill, or the initial recognition of assets or liabilities in a transaction that is not a business combination and that affects neither accounting profit or loss nor taxable income. A deferred income tax asset is recognized for the carryforward of unused tax losses, tax credits and deductible temporary differences to the extent that it is probable that future taxable profit will be available against which the unused tax losses, tax credits and deductible temporary differences can be utilized. The future taxable profit depends on reversing taxable temporary differences. When there are insufficient taxable temporary differences, the probability of future taxable profit (including the reversal of temporary differences) should be considered. The carrying amount of a deferred income tax asset is reviewed at the end of each reporting period and is reduced to the extent that it is no longer probable that sufficient taxable profit will be available to allow the benefit of part or all of that deferred income tax asset to be utilized. Deferred income tax assets and liabilities are measured at the tax rates that are expected to apply to the period when the asset is realized or the liability is settled, based on tax rates (and tax laws) that have been enacted or substantively enacted by the end of the reporting period. Deferred income tax assets and liabilities are offset only if there is a legally enforceable right to offset the related current income tax liabilities and assets, and they relate to income taxes levied by the same tax authority and they intend to settle current income tax liabilities and assets on a net basis.
Earnings per share	Earnings per share Management calculates basic earnings per share (“EPS”) data for POSCO’s ordinary shares, which is presented at the end of the statement of comprehensive income. Basic EPS is calculated by dividing profit attributable to ordinary shareholders of POSCO by the weighted average number of ordinary shares outstanding during the period, adjusted for own shares held.
Operating segments	Operating segments An operating segment is a component of the Company that : a) engages in business activities from which it may earn revenues and incur expenditures, including revenues and expenses that relate to transactions with any of the Company’s other components, b) whose operating results are regularly reviewed by the Company’s chief operating decision maker (“CODM”) to make decisions about resources to be allocated to the segment and assess its performance and for which discrete financial information is available. Management has determined that the CODM of the Company is the CEO. With regard to construction segment, segment profit and loss is determined in the same way that consolidated profit after tax for the period is generally determined under IFRS except that revenues and expenses from the development and sale of certain residential real estate are determined by reference to the stage of completion of the contact activity at the end of the reporting period, while in the consolidated financial statements, they are recognized when an individual unit of residential real estate is delivered to the buyer. No adjustments are made for corporate allocations to segment profit and loss. In addition, segment assets and liabilities are generally measured based on total assets and liabilities in accordance with IFRS without any adjustment for corporate allocations, except that assets and liabilities in connection with the construction and sale of residential real estate are determined by reference to the stage of completion of the contract activity at the end of each period. For the other segments, segment profit and loss is determined the same way that consolidated net after tax profit for the period is generally determined under IFRS without any adjustment for corporate allocations. The accounting policies used by each segment are consistent with the accounting policies used in the preparation of the consolidated financial statements. Segment assets and liabilities are generally measured based on total assets and liabilities in accordance with IFRS without any adjustment for corporate allocations. Also, segment assets and liabilities are based on the separate financial statements of the entities instead of on consolidated basis. In addition, there are varying levels of transactions amongst the reportable segments. These transactions include sales of property, plant and assets, and rendering of construction service and so on. Segment results that are reported to the CEO include items directly attributable to a segment and items allocated on a reasonable basis. Segment capital expenditure is the total cost incurred during the period to acquire property, plant and equipment, and intangible assets other than goodwill.
New standards and interpretations not yet adopted	New standards and interpretations not yet adopted The following new standard has been published but is not mandatory for the Company for annual period beginning on January 1, 2018, and the Company has not early adopted them. (a) IFRS No. 16 “Leases” The Company will apply IFRS No. 16 “Leases” for the year beginning on January 1, 2019. The Company is evaluating analysis of financial impact resulting from adoption of new standards and the estimated effect on the consolidated financial statements at the date of initial application based on current situation as of December 31, 2018. However, a reasonable estimation of financial impact is not determined since the analysis of financial impact is not completed. IFRS No. 16 “Leases” replaces existing leases guidance, including IAS No. 17 “Leases”, IFRIC No. 4 “Determining whether an Arrangement contains a Lease”, SIC No. 15 “Operating Leases-Incentives” and SIC No. 27 “Evaluating the Substance of Transactions Involving the Legal Form of a Lease”. IFRS No. 16 introduces a single accounting model that requires a lessee to recognize lease related asset and liability in the financial statements. A lessee is required to recognize a right-of-use asset representing its right to use the underlying leased asset and a lease liability representing its obligation to make lease payments. The lessee may elect not to apply the requirements to short-term lease with a term of 12 months or less at the commencement date or low value assets. Accounting treatment for lessor is similar to the existing standard which classifies lease into finance and operating lease. 1) Leases in which the Company is a lessee Upon adoption of IFRS No. 16, the Company will recognize new assets and liabilities for its operating leases. The nature of expenses related to those leases will change because the Company will recognize a deprecation charge for right-of-use assets and interest expense on lease liabilities. Previously, the Company recognized operating lease expense on a straight-line basis over the term of the lease term. It is expected that there will be no significant impact on finance leases. As of the authorization date for issuance of these consolidated financial statements, the Company is still evaluating whether certain arrangements related to the use of vessels, land, warehouses and factory facilities contain leases that shall be accounted for in accordance with IFRS No. 16. The outcome of such evaluations may have significant impact on the Company’s consolidated financial statements upon adoption of IFRS No. 16. As a lessee, the Company shall apply IFRS No. 16 using one of the following two transition methods; (a) retrospectively to each prior reporting period presented in accordance with IAS No. 8 “Accounting Policies, Changes in Accounting Estimates and Errors”; or (b) retrospectively with the cumulative effect of initially applying this standard recognized at the date of initial application. The Company intends to apply the modified retrospective approach when initially applying IFRS No. 16 as of January 1, 2019, the date of initial application. Accordingly, the Company will recognize the accumulated effect resulting from initial application of IFRS No. 16 as retained earnings of the Company at the date of initial application and not restate the financial statements for comparative periods. The Company plans to apply the practical expedient to grandfather the definition of a lease on transition. This means that it will apply IFRS No. 16 to all contracts entered into before January 1, 2019 and identified as leases in accordance with IAS No. 17 and IFRIC No. 4. 2) Leases in which the Company is a lessor As a lessor, the Company expects to have no significant impact on its financial statements since the present lease accounting treatment is not significantly different from applying IFRS No. 16. (b) IFRIC No. 23 “Uncertainty over Tax Treatments” If there is an uncertainty on tax treatment such as dispute of a particular tax treatment by the taxation authority, the Company determines whether it is probable that the taxation authority will accept an uncertain tax treatment in determining taxable profit, tax bases, unused tax losses, unused tax credits or tax rates. If the Company concludes it is probable that the taxation authority will accept an uncertain tax treatment, the Company determines the taxable profit (tax loss), tax bases, unused tax losses, unused tax credits or tax rates consistently with the tax treatment used or planned to be used in its income tax filings. If the Company concludes it is not probable that the taxation authority will accept an uncertain tax treatment, the Company reflects the effect of uncertainty for each uncertain tax treatment by using either of the most likely amount or the expected value depending on which method the entity expects to better predict the resolution of the uncertainty. The application of IFRIC No. 23 “Uncertainty over Tax Treatments” is mandatory for the year beginning on January 1, 2019. The Company expects the adoption of the standard will not have significant impact on consolidated financial statements.

General Information (Tables)

General Information (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
POSCO's Shareholders	As of December 31, 2018, POSCO’s shareholders are as follows: Shareholder’s name Number of shares Ownership (%) National Pension Service 9,342,192 10.72 BlackRock Fund Advisors (*1,2,3) 4,549,553 5.22 Nippon Steel & Sumitomo Metal Corporation (*1) 2,894,712 3.32 GIC Private Limited 2,016,887 2.31 KB Financial Group Inc. and subsidiaries (*2) 2,001,820 2.30 Others 66,381,671 76.13 87,186,835 100.00 (*1) Includes American Depository Receipts (ADRs) of POSCO, each of which represents 0.25 share of POSCO’s common share which has par value of ￦ (*2) Includes shares held by subsidiaries and others. (*3) The number of shares held by the shareholder based on the information in the status report of large-scale shareholders filed with Korea Exchange on October 4, 2018.
Details of Consolidated Subsidiaries	As of December 31, 2018, the shares of POSCO are listed on the Korea Exchange, while its ADRs are listed on the New York Stock Exchange. (b) Consolidated subsidiaries Details of consolidated subsidiaries as of December 31, 2017 and 2018 are as follows: Principal operations Ownership (%) December 31, 2017 December 31, 2018 POSCO Subsidiaries Total POSCO Subsidiaries Total Region [Domestic] POSCO ENGINEERING & CONSTRUCTION., CO., LTD. Engineering and construction 52.80 — 52.80 52.80 — 52.80 Pohang POSCO Processing & Service Steel sales and trading 93.95 0.45 94.40 93.95 0.45 94.40 Seoul POSCO COATED & COLOR STEEL Co., Ltd. Coated steel manufacturing 56.87 — 56.87 56.87 — 56.87 Pohang POSCO ICT Computer hardware and software distribution 65.38 — 65.38 65.38 — 65.38 Pohang POSCO Research Institute Economic research and consulting 100.00 — 100.00 100.00 — 100.00 Seoul POSMATE Business facility maintenance 83.83 16.17 100.00 59.80 40.20 100.00 Seoul POSCO A&C Architecture and consulting 100.00 — 100.00 100.00 — 100.00 Seoul POSCO Venture Capital Co., Ltd. Investment in venture companies 95.00 — 95.00 95.00 — 95.00 Pohang eNtoB Corporation Electronic commerce 7.50 53.63 61.13 7.50 53.63 61.13 Seoul POSCO CHEMTECH Refractories manufacturing and sales 60.00 — 60.00 60.00 — 60.00 Pohang POSCO-Terminal Co., Ltd. Transporting and warehousing 51.00 — 51.00 51.00 — 51.00 Gwangyang POSCO M-TECH Packing materials manufacturing and sales 48.85 — 48.85 48.85 — 48.85 Pohang POSCO ENERGY CO., LTD. Generation of electricity 89.02 — 89.02 89.02 — 89.02 Seoul POSCO NIPPON STEEL RHF JOINT VENTURE.CO., Ltd. Steel byproduct manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Pohang MegaAsset Co., Ltd. Real estate rental and sales — 100.00 100.00 — 100.00 100.00 Incheon Future Creation Fund Postech Early Stage account Investment in venture companies — 40.00 40.00 — 40.00 40.00 Seoul POSCO WOMAN’S FUND Investment in venture companies — 40.00 40.00 — 40.00 40.00 Seoul SPH Co, Ltd. House manufacturing and management — 100.00 100.00 — 100.00 100.00 Incheon Posco Group University Education service and real estate business 100.00 — 100.00 100.00 — 100.00 Incheon HOTEL LAONZENA Hotel business — 100.00 100.00 — 100.00 100.00 Daegu Growth Ladder POSCO K-Growth Investment in venture companies — 50.00 50.00 — 50.00 50.00 Pohang 2015 POSCO New technology II Fund Investment in venture companies — 25.00 25.00 — 25.00 25.00 Pohang Posco e&c Songdo International Building Non-residential — 100.00 100.00 — 100.00 100.00 Seoul POSCO ES MATERIALS CO., Ltd. Secondary and storage battery manufacturing 75.32 — 75.32 90.00 — 90.00 Gumi POSCO Research & Technology Intellectual Property Services and consulting 100.00 — 100.00 100.00 — 100.00 Seoul Poscoene Refuse derived fuel and power generation — 100.00 100.00 — 100.00 100.00 Seoul POSCO Humans Construction 90.30 — 90.30 90.30 — 90.30 Pohang Mapo Hibroad Parking Co., Ltd. Construction — 71.00 71.00 — 71.00 71.00 Seoul BLUE O&M Co., Ltd. Engineering service — 100.00 100.00 — 100.00 100.00 Pohang Busan E&E Co., Ltd. Refuse derived fuel and power generation 70.00 — 70.00 70.00 — 70.00 Busan POSCO Family Strategy Fund Investment in venture companies 69.91 30.09 100.00 69.91 30.09 100.00 Pohang POSCO DAEWOO Corporation Trading, energy & resource development and others 62.90 0.04 62.94 62.90 0.04 62.94 Seoul Pohang Scrap Recycling Distribution Center Co., Ltd. Steel processing and sales — 51.00 51.00 — 51.00 51.00 Pohang PSC Energy Global Co., Ltd. Investment in energy industry — 100.00 100.00 — 100.00 100.00 Pohang Suncheon Eco Trans Co., Ltd Train manufacturing and management 100.00 — 100.00 100.00 — 100.00 Suncheon Songdo Development PMC (Project Management Company) LLC. Housing business agency — — — — 100.00 100.00 Incheon POSPower Co., Ltd. (*1) Generation of electricity — 100.00 100.00 — — — Samcheok POCA STEM Co., Ltd. Stem cell medicine development — 100.00 100.00 — — — Seoul Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 Private equity trust 97.47 — 97.47 — — — Seoul Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust Private equity trust 99.01 — 99.01 — — — Seoul Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 Private equity trust — 99.67 99.67 — — — Seoul [Foreign] POSCO America Corporation Steel trading 99.45 0.55 100.00 99.45 0.55 100.00 USA POSCO AUSTRALIA PTY LTD Raw material sales & mine development 100.00 — 100.00 100.00 — 100.00 Australia POSCO Canada Ltd. Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCAN Elkview Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCO Asia Co., Ltd. Steel and raw material trading 100.00 — 100.00 100.00 — 100.00 China POSCO-CTPC Co., Ltd. Steel manufacturing and sales 56.60 43.40 100.00 61.91 38.09 100.00 China POSCO E&C Vietnam Co., Ltd. Steel structure manufacturing and sales — 100.00 100.00 — 100.00 100.00 Vietnam Zhangjiagang Pohang Stainless Steel Co., Ltd. Stainless steel manufacturing and sales 58.60 23.88 82.48 58.60 23.88 82.48 China POSCO(Guangdong) Coated Steel Co., Ltd. Plating steel sheet manufacturing and sales 87.04 10.04 97.08 87.04 10.04 97.08 China POSCO (Thailand) Company Limited Steel manufacturing and sales 88.58 11.42 100.00 88.58 11.42 100.00 Thailand Myanmar POSCO Steel Co., Ltd Zinc relief manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Myanmar POSCO-MKPC SDN BHD Steel manufacturing and sales 44.69 25.31 70.00 44.69 25.31 70.00 Malaysia Qingdao Pohang Stainless Steel Co., Ltd. Stainless steel manufacturing and sales 70.00 30.00 100.00 70.00 30.00 100.00 China POSCO(Suzhou) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO-China Qingdao Processing Center Co., Ltd. Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 China POS-ORE Iron ore sales and sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-China Holding Corp. Holding company 100.00 — 100.00 100.00 — 100.00 China POSCO JAPAN Co., Ltd. Steel trading 100.00 — 100.00 100.00 — 100.00 Japan POS-CD Coal sales — 100.00 100.00 — 100.00 100.00 Australia POS-GC Coal sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-India Private Limited Steel manufacturing and sales 99.99 — 99.99 99.99 — 99.99 India POSCO-India Pune Processing Center. Pvt. Ltd. Steel manufacturing and sales 65.00 — 65.00 65.00 — 65.00 India POSCO Japan PC CO., LTD Steel manufacturing and sales — 86.12 86.12 — 86.12 86.12 Japan POSCO-CFPC Co., Ltd. Steel manufacturing and sales 39.60 60.40 100.00 39.60 60.40 100.00 China POSCO E&C CHINA Co., Ltd. Civil engineering and construction — 100.00 100.00 — 100.00 100.00 China POSCO MPPC S.A. de C.V. Steel manufacturing and sales 21.02 75.29 96.31 21.02 75.29 96.31 Mexico Zhangjigang Pohang Port Co., Ltd. Loading and unloading service — 100.00 100.00 — 100.00 100.00 China POSCO-VIETNAM Co., Ltd. Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Vietnam POSCO MEXICO S.A. DE C.V. Automotive steel sheet manufacturing and sales 84.84 15.16 100.00 83.28 14.88 98.16 Mexico POSCO-Poland Wroclaw Processing Center Sp. z o. o. Steel manufacturing and sales 60.00 — 60.00 60.00 — 60.00 Poland POS-NP Coal sales — 100.00 100.00 — 100.00 100.00 Australia POSCO DAEWOO WAIGAIQIAO SHANGHAI CO., LTD Intermediary trade & bonded warehouse operation — 100.00 100.00 — 100.00 100.00 China PT. Bio Inti Agrindo Forest resources development — 85.00 85.00 — 85.00 85.00 Indonesia POSCO ENGINEERING AND CONSTRUCTION AUSTRALIA Iron ore development and sales — 100.00 100.00 — 100.00 100.00 Australia POSCO-TISCO (JILIN) PROCESSING CENTER Co., Ltd. Steel manufacturing and sales 50.00 10.00 60.00 50.00 10.00 60.00 China POSCO Thainox Public Company Limited STS cold-rolled steel manufacturing and sales 84.88 — 84.88 84.66 — 84.66 Thailand Hunchun Posco Hyundai Logistics Logistics — 80.00 80.00 — 80.00 80.00 China POSCO DAEWOO VIETNAM CO., LTD Trading business — 100.00 100.00 — 100.00 100.00 Vietnam POSCO(Chongqing) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China SUZHOU POSCO-CORE TECHNOLOGY CO., LTD. Component manufacturing and sales — 100.00 100.00 — 100.00 100.00 China PT.Krakatau Posco Chemtech Calcination Quicklime manufacturing and sales — 80.00 80.00 — 80.00 80.00 Indonesia POSCO AFRICA (PROPRIETARY) LIMITED Mine development 100.00 — 100.00 100.00 — 100.00 South POSCO ICT BRASIL IT service and engineering — 100.00 100.00 — 100.00 100.00 Brazil LA-SRDC Scrap manufacturing — 100.00 100.00 — 100.00 100.00 USA POSCO Center Beijing Real estate development, rental and management — 100.00 100.00 — 100.00 100.00 China POSCO AMERICA COMERCIALIZADORA S DE RL DE CV Human resource service — 100.00 100.00 — 100.00 100.00 Mexico POSCO(Guangdong) Automotive Steel Co., Ltd. Steel manufacturing and sales 83.64 10.00 93.64 83.64 10.00 93.64 China POSCO-Malaysia SDN. BHD. Steel manufacturing and sales 81.79 13.63 95.42 81.79 13.63 95.42 Malaysia PT KRAKATAU BLUE WATER Wastewater treatment facilities operation and maintenance — 67.00 67.00 — 67.00 67.00 Indonesia POSCO DAEWOO MYANMAR CORPORATION LIMITED Trading business — 100.00 100.00 — 100.00 100.00 Myanmar POSCO-Italy Processing Center Stainless steel sheet manufacturing and sales 80.00 10.00 90.00 80.00 10.00 90.00 Italy POSCO DAEWOO E&P CANADA CORPORATION Crude oil and natural gas mining — 100.00 100.00 — 100.00 100.00 Canada Myanmar POSCO C&C Company, Limited. Steel manufacturing and sales — 70.00 70.00 — 70.00 70.00 Myanmar POSCO ICT VIETNAM IT service and electric control engineering — 100.00 100.00 — 100.00 100.00 Vietnam Daewoo Global Development. Pte., Ltd Real estate development — 81.51 81.51 — 81.51 81.51 Myanmar Myanmar POSCO Engineering & Construction Company, Limited. Construction and engineering service — 100.00 100.00 — 100.00 100.00 Myanmar POS-Minerals Mine development management and sales — 100.00 100.00 — 100.00 100.00 USA POSCO(Wuhu) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 68.57 31.43 100.00 68.57 31.43 100.00 China POSCO Engineering and Construction India Private Limited Civil engineering and construction — 100.00 100.00 — 100.00 100.00 India POSCO COATED STEEL (THAILAND) CO., LTD. Automotive steel sheet manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Thailand Daewoo Amara Company Limited Real estate development — 85.00 85.00 — 85.00 85.00 Myanmar Daewoo Power and Infra (PTY) Limited Electricity — 100.00 100.00 — 100.00 100.00 South Africa POSMATE-CHINA CO., LTD Business facility maintenance — 100.00 100.00 — 100.00 100.00 China Daewoo Precious Resources Co., Ltd. Resources development — 70.00 70.00 — 70.00 70.00 Myanmar POSCO-Mexico Villagran Wire-rod Steel manufacturing and sales 56.75 10.00 66.75 56.75 10.00 66.75 Mexico POSCO ChengDu Processing Center Steel manufacturing and sales 33.00 10.00 43.00 33.00 10.00 43.00 China POSCO SUZHOU PROCESSING CENTER CO., LTD. Steel manufacturing and sales 30.00 70.00 100.00 30.00 70.00 100.00 China POSCO E&C SMART S DE RL DE CV Civil engineering and construction — 100.00 100.00 — 100.00 100.00 Mexico POSCO Philippine Manila Processing Center, Inc. Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 Philippines POSCO E&C HOLDINGS CO., Ltd. Holding company — 100.00 100.00 — 100.00 100.00 Thailand POSCO E&C (THAILAND) CO., Ltd. Construction and engineering — 100.00 100.00 — 100.00 100.00 Thailand Daewoo Power PNG Ltd. Electricity production — 100.00 100.00 — 100.00 100.00 Papua New PT.Krakatau Posco Social Enterprise Social enterprise — 100.00 100.00 — 100.00 100.00 Indonesia Ventanas Philippines Construction Inc Construction — 100.00 100.00 — 100.00 100.00 Philippines POSCO E&C Mongolia Construction and engineering service — 100.00 100.00 — 100.00 100.00 Mongolia POSCO Gulf SFC LLC Steel manufacturing and sales — 97.76 97.76 — 65.72 65.72 United Arab SANPU TRADING Co., Ltd. Raw material trading — 70.04 70.04 — 70.04 70.04 China Zhangjiagang BLZ Pohang International Trading Steel Intermediate trade — 100.00 100.00 — 100.00 100.00 China POSCO RU Limited Liability Company Trade and business development 100.00 — 100.00 100.00 — 100.00 Russia Golden Lace DAEWOO Company Limited Rice processing — 60.00 60.00 — 60.00 60.00 Myanmar POSCO ICT - IT service and DVR business — 100.00 100.00 — 100.00 100.00 China Pos-Sea Steel Intermediate trade — 100.00 100.00 — 100.00 100.00 Singapore POSCO Europe Steel Distribution Center Logistics & Steel sales 50.00 20.00 70.00 50.00 20.00 70.00 Slovenia POSCO ENGINEERING (THAILAND) CO., LTD. Construction and engineering service — 100.00 100.00 — 100.00 100.00 Thailand POSCO VST CO., LTD. Stainless steel sheet manufacturing and sales 95.65 — 95.65 95.65 — 95.65 Vietnam POSCO DAEWOO UKRAINE LLC Grain sales — 100.00 100.00 — 100.00 100.00 Ukraine Zhangjiagang Pohang Refractories Co., Ltd. Refractory materials sales & furnace maintenance — 51.00 51.00 — 51.00 51.00 China POSCO Maharashtra Steel Private Limited Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 India POSCO INDIA HOLDINGS PRIVATE LIMITED Steel manufacturing and sales 93.34 1.98 95.32 93.34 1.98 95.32 India POSCO TNPC Otomotiv Celik San. Ve Tic. A.S Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Turkey POSCO VIETNAM HOLDINGS CO., LTD Steel manufacturing and sales 83.54 5.29 88.83 83.54 5.29 88.83 Vietnam POSCO(Liaoning) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO-Indonesia Jakarta Processing Center Steel manufacturing and sales 65.00 20.00 85.00 65.00 20.00 85.00 Indonesia PT.MRI Mine development 65.00 — 65.00 65.00 — 65.00 Indonesia POSCO TMC INDIA PRIVATE LIMITED Steel manufacturing and sales — 100.00 100.00 — 100.00 100.00 India POSCO-AAPC Steel manufacturing and sales — 97.80 97.80 — 97.80 97.80 USA POSCO(Yantai) Automotive Processing Center Co., Ltd. Steel manufacturing and sales 90.00 10.00 100.00 90.00 10.00 100.00 China POSCO India Steel Distribution Center Private Ltd. Steel logistics — 100.00 100.00 — 100.00 100.00 India POSCO China Dalian Plate Processing Center Co., Ltd. Plate manufacturing and sales 80.00 10.00 90.00 79.52 11.70 91.22 China POSCO-South Asia Company Limited Steel sales 100.00 — 100.00 100.00 — 100.00 Thailand POSCO SS VINA Co., Ltd Steel manufacturing and sales 100.00 — 100.00 100.00 — 100.00 Vietnam PT.POSCO ICT INDONESIA IT service and electric control engineering — 66.99 66.99 — 66.99 66.99 Indonesia POSCO NCR Coal Ltd. Coal sales — 100.00 100.00 — 100.00 100.00 Canada POSCO WA PTY LTD Iron ore sales & mine development 100.00 — 100.00 100.00 — 100.00 Australia POSCO AUSTRALIA GP PTY LIMITED Resource development — 100.00 100.00 — 100.00 100.00 Australia POSCO DAEWOO POWER (PNGPOM) LTD. Electricity production — 100.00 100.00 — 100.00 100.00 Papua New PT. KRAKATAU POSCO ENERGY Electricity production construction and operation — 90.00 90.00 — 90.00 90.00 Indonesia POSCO DAEWOO AMERICA CORP. Trading business — 100.00 100.00 — 100.00 100.00 USA POSCO DAEWOO DEUTSCHLAND GMBH Trading business — 100.00 100.00 — 100.00 100.00 Germany POSCO DAEWOO JAPAN Corp Trading business — 100.00 100.00 — 100.00 100.00 Japan POSCO DAEWOO SINGAPORE PTE LTD. Trading business — 100.00 100.00 — 100.00 100.00 Singapore POSCO DAEWOO ITALIA S.R.L. Trading business — 100.00 100.00 — 100.00 100.00 Italy POSCO DAEWOO CHINA CO., LTD Trading business — 100.00 100.00 — 100.00 100.00 China Daewoo Textile LLC Textile manufacturing — 100.00 100.00 — 100.00 100.00 Uzbekistan POSCO DAEWOO AUSTRALIA HOLDINGS PTY. LTD. Resource development — 100.00 100.00 — 100.00 100.00 Australia POSCO MAURITIUS LIMITED Coal development and sales — 100.00 100.00 — 100.00 100.00 Mauritius PT. KRAKATAU POSCO Steel manufacturing and sales 70.00 — 70.00 70.00 — 70.00 Indonesia POSCO DAEWOO MEXICO S.A. de C.V. Trading business — 100.00 100.00 — 100.00 100.00 Mexico Daewoo International Guangzhou Corp. Trading business — 100.00 100.00 — 100.00 100.00 China POSCO DAEWOO MALAYSIA SDN BHD Trading business — 100.00 100.00 — 100.00 100.00 Malaysia PT.POSCO INDONESIA INTI Mine development 99.99 — 99.99 99.99 — 99.99 Indonesia POSCO DAEWOO SHANGHAI CO., LTD. Trading business — 100.00 100.00 — 100.00 100.00 China PGSF, L.P. Investment in bio tech Industry — 100.00 100.00 — 100.00 100.00 USA POSCO DAEWOO INDIA PVT., LTD. Trading business — 100.00 100.00 — 100.00 100.00 India POSCO(Dalian) IT Center Development Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 China PT. POSCO E&C INDONESIA Civil engineering and construction — 100.00 100.00 — 100.00 100.00 Indonesia HUME COAL PTY LTD Raw material manufacturing — 100.00 100.00 — 100.00 100.00 Australia Brazil Sao Paulo Steel Processing Center Steel manufacturing and sales — 76.00 76.00 — 76.00 76.00 Brazil DAESAN (CAMBODIA) Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 Cambodia POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. Construction — 100.00 100.00 — 100.00 100.00 Brazil POSCO ASSAN TST STEEL INDUSTRY Steel manufacturing and sales 60.00 10.00 70.00 60.00 10.00 70.00 Turkey HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd. Real estate development and investment — 100.00 100.00 — 100.00 100.00 Hongkong POS-LT Lithium mining investment — — — — 100.00 100.00 Australia POSCO SINGAPORE LNG TRADING PTE. LTD. LNG trading — — — 50.00 50.00 100.00 Singapore ZHEJIANG POSCO-HUAYOU Anode material manufacturing — — — 100.00 — 100.00 China POSCO Argentina S.A.U. Mineral exploration/manufacturing/sales — — — 100.00 — 100.00 Argentina POSCO RUS LLC Trading and business development 90.00 10.00 100.00 — — — Russia POSCO-CDSFC Steel structure manufacturing 50.20 49.80 100.00 — — — China POSCO MESDC S.A. DE C.V. Logistics & Steel sales — 56.80 56.80 — — — Mexico KIS Devonian Canada Corporation Petroleum gas extraction — 100.00 100.00 — — — Canada POSCO E&C VENEZUELA C.A. Civil engineering and construction — 100.00 100.00 — — — Venezuela PT PEN INDONESIA Construction — 100.00 100.00 — — — Indonesia POSCO Engineering and Construction — UZ Civil engineering and construction — 100.00 100.00 — — — Uzbekistan (*1) Reclassified to associate from subsidiary during the year ended December 31, 2018.
Details of Non-controlling Interest	(c) Details of non-controlling 1) December 31, 2016 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 4,038,313 460,376 397,370 5,163,436 713,039 9,696,140 20,468,674 Non-current 4,510,085 3,304,292 243,401 1,710,398 3,038,665 7,749,277 20,556,118 Current liabilities (3,662,811 ) (1,120,077 ) (109,016 ) (3,284,090 ) (937,668 ) (9,669,053 ) (18,782,715 ) Non-current (1,681,182 ) (2,337,612 ) (2,337 ) (855,791 ) (2,172,226 ) (2,856,498 ) (9,905,646 ) Equity 3,204,405 306,979 529,418 2,733,953 641,810 4,919,866 12,336,431 Non-controlling 1,271,750 92,094 211,767 1,290,450 514,200 945,962 4,326,223 Sales 15,417,550 1,244,711 1,076,455 5,352,395 1,657,890 23,251,563 48,000,564 Profit (loss) for the period 113,832 (187,151 ) 41,829 (760,187 ) (130,809 ) (461,034 ) (1,383,520 ) Profit (loss) attributable to non-controlling 45,177 (56,145 ) 16,732 (358,815 ) (14,357 ) (312,297 ) (679,705 ) Cash flows from operating activities 337,338 45,672 30,295 (211,182 ) 18,107 53,050 273,280 Cash flows from investing activities (35,054 ) (8,804 ) (42,021 ) (102,939 ) (1,047 ) (253,206 ) (443,071 ) Cash flows from financing activities (before dividends to non-controlling (295,226 ) (36,286 ) (1,250 ) (20,953 ) (2,875 ) 204,797 (151,793 ) Dividend to non-controlling (22,597 ) — (4,726 ) (14,800 ) (24,378 ) (7,349 ) (73,850 ) Effect of exchange rate fluctuation on cash held 10 67 1 760 — 1,687 2,525 Net increase (decrease) in cash and cash equivalents (15,529 ) 649 (17,701 ) (349,114 ) (10,193 ) (1,021 ) (392,909 ) 2) December 31, 2017 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 4,483,544 557,041 441,325 4,878,251 1,054,538 8,579,813 19,994,512 Non-current 4,590,394 2,771,504 316,724 2,444,616 2,859,824 6,676,559 19,659,621 Current liabilities (4,221,443 ) (1,237,255 ) (145,649 ) (3,896,680 ) (785,462 ) (8,313,902 ) (18,600,391 ) Non-current (1,549,013 ) (1,933,247 ) (970 ) (833,403 ) (2,200,065 ) (2,048,454 ) (8,565,152 ) Equity 3,303,482 158,043 611,430 2,592,784 928,835 4,894,016 12,488,590 Non-controlling 1,224,303 47,413 244,572 1,223,816 762,390 974,941 4,477,435 Sales 20,891,526 1,635,837 1,163,918 5,794,532 1,578,026 23,547,072 54,610,911 Profit (loss) for the period 115,321 (117,729 ) 101,019 169,011 70,795 258,053 596,470 Profit (loss) attributable to non-controlling 42,739 (35,318 ) 40,408 79,775 7,770 39,605 174,979 Cash flows from operating activities 128,875 (27,817 ) 20,042 (84,840 ) 30,295 140,418 206,973 Cash flows from investing activities (86,365 ) (5,502 ) (18,699 ) (171,924 ) (2,792 ) (63,621 ) (348,903 ) Cash flows from financing activities (before dividends to non-controlling (19,295 ) 31,782 8 150,801 220,317 (38,090 ) 345,523 Dividend to non-controlling (22,597 ) — (7,088 ) — (24,183 ) (12,777 ) (66,645 ) Effect of exchange rate fluctuation on cash held (459 ) (147 ) (6 ) (3,541 ) — (15,532 ) (19,685 ) Net increase (decrease) in cash and cash equivalents 159 (1,684 ) (5,743 ) (109,504 ) 223,637 10,398 117,263 3) December 31, 2018 POSCO PT. POSCO POSCO POSCO POSCO ENERGY CO., LTD. Others Total (in millions of Won) Current assets ￦ 5,311,596 615,491 416,284 4,100,967 825,241 9,137,798 20,407,377 Non-current 4,363,490 2,730,865 460,905 1,911,844 2,767,203 5,493,324 17,727,631 Current liabilities (4,724,056 ) (1,368,498 ) (140,268 ) (3,007,029 ) (1,197,845 ) (8,026,474 ) (18,464,170 ) Non-current (1,563,107 ) (1,754,797 ) (10,767 ) (608,089 ) (1,445,288 ) (1,925,084 ) (7,307,132 ) Equity 3,387,923 223,061 726,154 2,397,693 949,311 4,679,564 12,363,706 Non-controlling 1,255,728 66,918 290,461 1,131,733 335,203 929,506 4,009,549 Sales 23,314,595 1,871,634 1,340,984 6,799,292 1,841,187 24,721,939 59,889,631 Profit (loss) for the period 113,196 54,257 142,918 290,131 (73,948 ) (56,151 ) 470,403 Profit (loss) attributable to non-controlling 41,956 16,277 57,167 136,944 (8,116 ) (101,156 ) 143,072 Cash flows from operating activities (61,173 ) 89,131 29,865 207,729 16,211 14,869 296,632 Cash flows from investing activities (12,780 ) (6,432 ) (15,801 ) 272,230 35,460 (13,199 ) 259,478 Cash flows from financing activities (before dividends to non-controlling 99,496 (82,295 ) — (400,499 ) (71,378 ) (16,094 ) (470,770 ) Dividend to non-controlling (22,862 ) — (8,270 ) — (19,813 ) (6,906 ) (57,851 ) Effect of exchange rate fluctuation on cash held 807 21 (17 ) 1,257 — 1,682 3,750 Net increase (decrease) in cash and cash equivalents 3,488 425 5,777 80,717 (39,520 ) (19,648 ) 31,239
Details of Associates	(d) Details of associates and joint ventures 1) Associates Details of associates as of December 31, 2017 and 2018 are as follows: Ownership (%) Investee Category of business 2017 2018 Region [Domestic] New Songdo International City Development, LLC Real estate rental 29.90 29.90 Seoul Gale International Korea, LLC Real estate rental 29.90 29.90 Seoul SNNC Raw material manufacturing and sales 49.00 49.00 Gwangyang KONES, Corp. Technical service 41.67 41.67 Gyeongju CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd Real estate development 29.53 29.53 Chungju DAEHO GLOBAL MANAGEMENT CO., LTD. Investment advisory service 35.82 35.82 Pohang Mokpo Deayang Industrial Corporation Real estate development and rental 27.40 27.40 Mokpo Gunggi Green Energy (*1) Electricity generation 19.00 19.00 Hwaseong Pohang Special Welding Co., Ltd. Welding material and tools manufacturing and sales 50.00 50.00 Pohang KoFC POSCO HANWHA KB Shared Growth NO. 2. Private Equity Fund (*1) Investment in new technologies 12.50 12.50 Seoul EQP POSCO Global NO1 Natural Resources Private Equity Fund Investment in new technologies 31.14 31.27 Seoul KC Chemicals CORP. (*1) Machinery manufacturing 19.00 19.00 Hwaseong Garolim Tidal Power Plant Co., Ltd Tidal power plant construction and management 32.13 32.13 Seosan POSTECH Social Enterprise Fund (*1) Investment in new technologies 9.17 9.17 Seoul QSONE Co., Ltd. Real estate rental and facility management 50.00 50.00 Seoul Chun-cheon Energy Co., Ltd Electricity generation 45.67 45.67 Chuncheon Keystone NO. 1 Private Equity Fund Private equity financial 40.45 40.45 Seoul Noeul Green Energy (*1) Electricity generation 10.00 10.00 Seoul Posco-IDV (*1) Investment in new technologies 17.86 17.86 Seoul Daesung Steel (*1) Steel sales 17.54 17.54 Busan Pohang E&E Co., LTD Investment in waste energy 30.00 30.00 Pohang POSCO Energy Valley Fund Investment in new technologies 20.00 20.00 Pohang 2016 PoscoPlutus New technology Fund Investment in new technologies 25.17 25.17 Seoul Hyundai Invest Guggenheim CLO Qualified Private Special Asset Trust No.2 Investment in new technologies 38.47 38.47 Seoul PoscoPlutus Bio Fund (*1) Investment in new technologies 11.97 11.97 Seoul PoscoPlutus Project Fund (*1) Investment in new technologies 11.91 11.91 Seoul Posco Agri-Food Export Fund Investment in new technologies 30.00 30.00 Seoul PoscoPlutus Project 2nd Project Fund (*1) Investment in new technologies 0.61 0.61 Seoul Posco Culture Contents Fund Investment in new technologies 31.67 31.67 Seoul PCC_Centroid 1st Fund Investment in new technologies 24.10 24.10 Seoul PCC Amberstone Private Equity Fund 1 (*1) Investment in new technologies 9.71 8.80 Seoul UITrans LRT Co., Ltd. Transporting 38.19 38.19 Seoul POSCO Advanced Technical Staff Fund (*1) Investment in new technologies 15.87 15.87 Seoul POSCO 4th Industrial Revolution Fund (*1) Investment in new technologies 20.00 19.05 Seoul Clean Gimpo Co., Ltd. Construction 29.58 29.58 Gimpo Incheon-Gimpo Expressway Co., Ltd. (*1) Construction 18.26 18.26 Anyang Pureun Tongyeong Enviro Co., Ltd. Sewerage treatment 20.40 20.40 Tongyeong Pure Gimpo Co., Ltd. Construction 28.79 28.79 Seoul POSCO PLANTEC Co., Ltd. (*2) Construction of industrial plant 73.94 73.94 Ulsan Postech Early Stage Fund (*1) Investment in new technologies 10.00 10.00 Pohang Posgreen Co., Ltd. (*1) Lime and plaster manufacturing 19.00 19.00 Gwangyang Clean Iksan Co., Ltd. Construction 23.50 23.50 Iksan Innovalley Co., Ltd. Real estate development 28.77 28.77 Yongin Applied Science Corp. Machinery manufacturing 23.87 22.89 Paju Pohang Techno Valley PFV Corporation (*3) Real estate development, supply and rental 57.39 57.39 Pohang BLUE OCEAN Private Equity Fund Private equity financial 27.52 27.52 Seoul Western Inland highway CO., LTD. (*4) Construction — 27.50 Incheon Metropolitan Outer Ring Expressway co., ltd. (*4) Investment in Expressway — 47.58 Incheon IT ENGINEERING CO., LTD. (*1,4) Vehicle engineering — 10.84 Seoul PCC Bio 1ST Fund (*1,4) Investment in new technologies — 13.46 Seoul INNOPOLIS Job Creation Fund II (*1,4) Investment in new technologies — 6.43 Seoul POSPower Co., Ltd. (*5) Generation of electricity — 34.00 Samcheok INKOTECH, INC. (*1,4) Electricity generation and sales — 10.00 Seoul PCC Social Enterprise Fund II (*1,4) Investment in venture companies — 16.67 Seoul PCC Amberstone Private Equity Fund II (*1,4) Private equity trust — 19.70 Seoul Synapse Fund (*1,4) Investment in new technologies — 16.26 Seoul NEXTRAIN Co., Ltd (*4) Service maintenance and management — 32.00 Incheon TK CHEMICAL CORPORATION (*1,4) Chemical — 8.80 Daegu Hanil-Daewoo Cement Co., Ltd. (*1,4) Cement — 15.00 Incheon Pohang Techno Valley AMC (*6) Construction 29.50 — Pohang [Foreign] VSC POSCO Steel Corporation Steel processing and sales 50.00 50.00 Vietnam POSCHROME (PROPRIETARY) LIMITED Raw material manufacturing and sales 50.00 50.00 South CAML RESOURCES PTY LTD Raw material manufacturing and sales 33.34 33.34 Australia Nickel Mining Company SAS Raw material manufacturing and sales 49.00 49.00 New PT. Wampu Electric Power Construction and civil engineering 20.00 20.00 Indonesia POSK (Pinghu) Steel Processing Center Co., Ltd. Steel processing and sales 20.00 20.00 China PT.INDONESIA POS CHEMTECH CHOSUN Ref Refractory manufacturing and sales 30.19 30.19 Indonesia NS-Thainox Steel manufacturing and sales 49.00 49.00 Vietnam Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd Tinplate manufacturing and sales 34.00 34.00 China PT. Tanggamus Electric Power (*1) Construction and civil engineering 17.50 17.50 Indonesia LLP POSUK Titanium Titanium manufacturing and sales 36.83 36.83 Kazakhstan LI3 ENERGY INC Resource development 26.06 26.06 Peru IMFA ALLOYS FINLEASE LTD Raw material manufacturing and sales 24.00 24.00 India KRAKATAU POS-CHEM DONG-SUH (*1) Chemical by-product manufacturing and sales 19.00 19.00 Indonesia 7623704 Canada Inc. (*1) Investments management 10.40 10.40 Canada Hamparan Mulya Resource development 45.00 45.00 Indonesia POS-SEAH Steel manufacturing and sales 25.00 25.00 China Eureka Moly LLC Raw material manufacturing and sales 20.00 20.00 USA PT. Batutua Tembaga Raya Raw material manufacturing and sales 22.00 22.00 Indonesia KIRIN VIETNAM CO., LTD (*1) Panel manufacturing 19.00 19.00 Vietnam POSCO SeAH Steel Wire (Nantong) Co., Ltd. Steel processing and sales 25.00 25.00 China POS-SeAH Steel manufacturing and sales 25.00 25.00 Thailand Jupiter Mines Limited (*1) Resource development 17.06 6.93 Australia SAMHWAN VINA CO., LTD (*1) Steel manufacturing and sales 19.00 19.00 Vietnam JB CLARK HILLS Construction 25.00 25.00 Philippines Saudi-Korean Company for Maintenance Properties Management LLC (*1) Building management 19.00 19.00 Saudi Sebang Steel Scrap sales 49.00 49.00 Japan NCR LLC Coal sales 29.41 29.41 Canada AMCI (WA) PTY LTD Iron ore sales & mine development 49.00 49.00 Australia SHANGHAI LANSHENG DAEWOO CORP. Trading 49.00 49.00 China SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. Trading 49.00 49.00 China General Medicines Company Ltd. Medicine manufacturing and sales 33.00 33.00 Sudan KOREA LNG LTD. Gas production and sales 20.00 20.00 England AES-VCM Electricity generation 30.00 30.00 Vietnam KG Power(M) SDN. BHD Resource development 20.00 20.00 Malaysia South-East Asia Gas Pipeline Company Ltd. Pipeline construction and management 25.04 25.04 Myanmar GLOBAL KOMSCO Daewoo LLC Cotton celluloid manufacturing and sales 35.00 35.00 Uzbekistan POSCO-Poggenamp Electrical Steel Pvt. Ltd. Steel processing and sales 26.00 26.00 India Qingdao Pohang DGENX Stainless SteelPipeCo., Ltd (*4) Exhaust meter manufacturing — 40.00 China SHINPOONG DAEWOO PHARMA VIETNAM CO., LTD (*1,4) Medicine production — 3.42 Vietnam ERAE Automotive Systems Mexico, S. DE R.L. DE C.V (*1,4) Automobile parts manufacturing — 7.65 Mexico (*1) Considering the composition of board of directors, the Company is able to exercise significant influence even though the Company’s percentage of ownership is below 20%. (*2) On September 30, 2015, in order to improve its financial standing and normalize operation, the associates reached a workout agreement with its Creditor Financial Institutions Committee. As a result, the Company lost its control and classified its shares as investment in associate. (*3) Considering the composition of board of directors, the Company does not have control and classified its shares as investment in an associate, even though the Company’s percentage of ownership is over 50%. (*4) These associates were newly established or acquired in 2018. (*5) Reclassified to associate from subsidiary during the year ended December 31, 2018. (*6) Excluded from associates due to liquidation during the year ended December 31, 2018.
Details of Joint Ventures	Details of joint ventures as of December 31, 2017 and 2018 are as follows: Ownership (%) Investee Category of business 2017 2018 Region [Domestic] POSCO MITSUBISHI CARBON TECHNOLOGY Steel processing and sales 60.00 60.00 Gwangyang POSCO-SGI Investment in new technologies 24.55 24.55 Seoul POSCO-KB Investment in new technologies 18.75 18.75 Seoul POSCO-NSC Investment in new technologies 16.67 16.67 Seoul PoscoPlutus Project 3rd Project fund Investment in new technologies 5.96 5.96 Seoul PCC Bio 2nd Fund (*1) Investment in new technologies — 19.72 Seoul PCC Material 3rd Fund (*1) Investment in new technologies — 2.38 Seoul PCC L&K IST FUND (*2) Investment in new technologies 10.00 — Seoul [Foreign] KOBRASCO Steel materials manufacturing and sales 50.00 50.00 Brazil USS-POSCO Cold-rolled steel manufacturing and sales 50.00 50.00 USA PT. POSMI Steel Indonesia Steel processing and sales 36.69 36.69 Indonesia United Spiral Pipe, LLC Material manufacturing and sales 35.00 35.00 USA CSP — Compania Siderurgica do Pecem Steel manufacturing and sales 20.00 20.00 Brazil BX STEEL POSCO Cold Rolled Sheet Co., Ltd. Steel processing and sales 25.00 25.00 China POSCO-SAMSUNG-Slovakia Processing Center Steel processing and sales 30.00 30.00 Slovakia VNS-DAEWOO Steel scrap processing and sales 40.00 50.00 Vietnam YULCHON MEXICO S.A. DE C.V. Tube for automobile manufacturing 19.00 19.00 Mexico Hyunson Engineering & Construction HYENCO Construction 4.90 4.89 Algeria POSCO E&C Saudi Arabia Civil engineering and construction 40.00 40.00 Saudi Pos-Austem Automotive parts manufacturing 19.90 19.90 China POS-InfraAuto Automotive parts manufacturing 16.20 16.20 China POS-AUSTEM Automotive parts manufacturing 11.10 11.10 China POS-AUSTEM Automotive parts manufacturing 13.00 13.00 China Kwanika Copper Corporation Energy & resource development 35.00 35.00 Canada DMSA/AMSA Energy & resource development 4.00 4.00 Madagascar Roy Hill Holdings Pty Ltd Energy & resource development 12.50 12.50 Australia POSCO-NPS Mine development 50.00 50.00 USA Korea Siberia Wood CJSC (*3) Forest resource development 50.00 — Russia (*1) These joint ventures were newly established in 2018. (*2) Excluded from joint ventures due to liquidation during the year ended December 31, 2018. (*3) Excluded from joint ventures due to the disposal of shares during the year ended December 31, 2018.
Consolidated Subsidiaries Acquired or Newly Established	(e) Newly included subsidiaries Consolidated subsidiaries acquired or newly established during the year ended December 31, 2018 are as follows: Company Date of addition Ownership (%) Reason POS-LT PTY LTD March 2018 100.00 New establishment POSCO SINGAPORE LNG TRADING PTE. LTD. June 2018 100.00 New establishment ZHEJIANG POSCO-HUAYOU ESM CO., LTD June 2018 100.00 New establishment POSCO Argentina S.A.U. October 2018 100.00 New establishment Songdo Development PMC (Project Management Company) LLC. October 2018 100.00 New establishment
Subsidiaries That Were Excluded From Consolidation	(f) Excluded subsidiaries Subsidiaries that were excluded from consolidation during the year ended December 31, 2018 are as follows: Company Date of exclusion Reason KIS Devonian Canada Corporation February 2018 Merged into POSCO DAEWOO E&P CANADA CORPORATION POSCO-CDSFC February 2018 Merged into POSCO China Dalian Plate Processing Center Co., Ltd. POCA STEM Co., Ltd. March 2018 Liquidation POSCO E&C VENEZUELA C.A. March 2018 Liquidation PT PEN INDONESIA March 2018 Merged into PT. POSCO E&C INDONESIA Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 April 2018 Disposal Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust May 2018 Disposal Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 May 2018 Disposal POSCO RUS LLC May 2018 Liquidation POSPower Co., Ltd. July 2018 Reclassification to an associate upon loss of control due to a decline in ownership POSCO MESDC S.A. DE C.V. August 2018 Merged into POSCO MEXICO S.A. DE C.V. POSCO Engineering and Construction — UZ November 2018 Liquidation

Statement of Compliance (Tables

Statement of Compliance (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Impact on Net of Tax on Transition to New Update on Retained Earnings and Non-controlling Interests	The following table summarizes the impact, net of tax, of transition to IFRS No. 15 on retained earnings and non-controlling Retained earnings Non-controlling interests (in millions of Won) Shipping services included in the sales contract ￦ (949 ) (156 ) Separate construction contract determined to be a single performance obligation 452 628 Variable consideration for sales discounts and price adjustments based on performance (2,613 ) 172 Change in revenue recognition method for contracts without enforceable right to payment (1,189 ) (1,115 ) Change in percentage of completion due to excessive use of materials (2,855 ) (1,512 ) Recognize prepaid contract cost as an expense (63,753 ) (56,993 ) ￦ (70,907 ) (58,976 )
Summary of Effects of Adoption of IFRS No. 15 to Company's Consolidated Statements of Financial Position and Consolidated Statements of Comprehensive Income	The effects of adoption of IFRS No. 15 to the Company’s consolidated statements of financial position and consolidated statements of comprehensive income as of and for the year ended December 31, 2018 are as follows. There is no material impact on the Company’s consolidated statement of cash flows for the year ended December 31, 2018. As reported Adjustments of IFRS No. 15 Amounts without IFRS No. 15 (in millions of Won) Consolidated financial statements of financial position Current assets ￦ 34,151,972 193,400 34,345,372 Trade accounts and notes receivable 9,130,204 86,293 9,216,497 Inventories 12,153,303 6,584 12,159,887 Other current assets 684,464 100,523 784,987 Non-current 44,625,019 (41,589 ) 44,583,430 Deferred tax assets 1,408,787 (41,589 ) 1,367,198 Current liabilities 19,430,577 21,605 19,452,182 Others payables 1,720,097 17,809 1,737,906 Current income tax liabilities 948,166 (640 ) 947,526 Provisions 298,453 (28,748 ) 269,705 Other current liabilities 2,090,307 33,184 2,123,491 Retained earnings 44,160,659 68,182 44,228,841 Non-controlling 3,347,257 62,024 3,409,281 Consolidated statements of comprehensive income Revenue ￦ 65,154,636 135 65,154,771 Cost of sales (57,129,060 ) 1,206,973 (55,922,087 ) Selling and administrative expenses (2,429,781 ) (1,204,764 ) (3,634,545 ) Finance costs (2,244,416 ) 178 (2,244,238 ) Profit before income taxes 3,616,016 2,522 3,618,538 Income tax expense (1,683,630 ) (2,198 ) (1,685,828 ) Profit 1,932,386 324 1,932,710
Summary of Impact, Net of Tax, of Transition to IFRS No. 9 on Reserves, Retained Earnings and Non-Controlling Interests	The following table summarizes the impact, net of tax, of transition to IFRS No. 9 on reserves, retained earnings and non-controlling Reserves Retained Non-controlling interests (in millions of Won) Classification to fair value through profit or loss in securities and select to fair value through other comprehensive income in equity securities (*1) ￦ (498,517 ) 498,517 — Recognition of expected credit losses — (51,450 ) (34,754 ) ￦ (498,517 ) 447,067 (34,754 ) (*1) Includes a decrease in reserve (capital adjustment arising from investments in equity-accounted investees) of ￦ ￦
Summary of Initial Application, Measurement Categories and Carrying Amounts of Financial Assets in Accordance with IAS No. 39 and IFRS No. 9	Original classification under IAS No. 39 Original amounts IAS No. 39 New classification under IFRS No. 9 New carrying amounts IFRS No. 9 (in millions of Won) Derivative assets Financial assets at fair value through ￦ 65,051 Fair value through ￦ 65,051 Hedging instrument 3,239 Hedging instrument 3,239 Cash and cash equivalents Loans and receivables 2,612,530 Amortized cost 2,612,530 Trade accounts and notes receivable (*1) Loans and receivables 8,901,867 Amortized cost 8,799,161 Other receivables (*1) Loans and receivables 2,195,466 Fair value through 1,898 Amortized cost 2,188,820 Equity securities (*2) Available-for-sale 1,421,295 Fair value through 17,812 Fair value through 1,403,483 Debt securities (*2) Available-for-sale 190,579 Fair value through 188,276 Held-to-maturity Fair value through 2,303 5,211 Amortized cost 5,211 Other Securities (*2) Available-for-sale 366,241 Fair value through 366,241 Deposit instruments Loans and receivables 1,358,311 Amortized cost 1,358,311 Short-term financial instruments Financial assets at 1,970 Fair value through 5,547,637 Loans and receivables 5,545,667 (*1) As a result of the adoption of IFRS No. 9, as of January 1, 2018, the date of initial application, loss allowance was increased by ￦ non-controlling ￦ ￦ (*2) As a result of the adoption of IFRS No. 9, as of January 1, 2018, the date of initial application, with respect to securities classified as fair value through profit or loss and equity securities determined fair value through other comprehensive income, reserves were decreased by ￦ ￦

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Estimated Useful Lives of Property, Plant and Equipment	The estimated useful lives for the current and comparative periods are as follows: Buildings 5-50 Structures 4-50 Machinery and equipment 4-25 Vehicles 3-20 Tools 3-10 Furniture and fixtures 3-20 Lease assets 3-30 Bearer plants 20 years
Estimated Useful Lives of Intangible Assets	Amortization of intangible assets except for goodwill is calculated on a straight-line basis over the estimated useful lives of intangible assets from the date that they are available for use. The residual value of intangible assets is zero. However, as there are no foreseeable limits to the periods over which club memberships are expected to be available for use, this intangible asset is determined as having an indefinite useful life and not amortized. Intellectual property rights 4-25 Development expense 3-5 Port facilities usage rights 4-75 Other intangible assets 2-15

Financial risk management (Tabl

Financial risk management (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Net Borrowing-to-Equity Ratio	Net borrowing-to-equity 2017 2018 (in millions of Won) Total borrowings ￦ 21,063,657 20,209,270 Less: Cash and cash equivalents 2,612,530 2,643,865 Net borrowings 18,451,127 17,565,405 Total equity 47,326,725 46,672,614 Net borrowings-to-equity 38.99 % 37.64 %

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Cash and Cash Equivalents	Cash and cash equivalents as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Cash ￦ 1,896 1,668 Demand deposits and checking accounts 1,259,813 1,471,891 Time deposits 360,985 538,130 Other cash equivalents 989,836 632,176 ￦ 2,612,530 2,643,865

Other Receivables (Tables)

Other Receivables (Tables)	12 Months Ended
	Dec. 31, 2018
Other receivables [member]
Statement [LineItems]
Summary of Financial Assets	Other receivables as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Loans ￦ 617,696 236,782 Other accounts receivable 960,543 954,030 Accrued income 179,971 220,066 Deposits 107,137 108,640 Others 18,925 16,201 Less: Allowance for doubtful accounts (248,266 ) (150,090 ) ￦ 1,636,006 1,385,629 Non-current Loans ￦ 874,158 731,344 Other accounts receivable 92,939 155,936 Accrued income 1,663 1,855 Deposits 122,485 152,072 Less: Allowance for doubtful accounts (212,069 ) (177,967 ) ￦ 879,176 863,240
Others [member]
Statement [LineItems]
Summary of Financial Assets	Other financial assets as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Derivatives assets held for trading ￦ 63,912 47,288 Debt securities — 2,987 Financial assets held for trading 1,970 — Available-for-sale 136,141 — Current portion of held-to-maturity 421 — Deposit instruments (*1,2) 1,297,769 1,931,518 Short-term financial instruments (*2) 5,545,667 6,099,303 ￦ 7,045,880 8,081,096 Non-current Derivatives assets held for trading ￦ 4,378 1,795 Equity securities (*3) — 1,238,630 Debt securities — 34,327 Other securities (*3) — 338,106 Available-for-sale (*3) 1,730,753 — Available-for-sale 54,439 — Available-for-sale 56,782 — Held-to-maturity 4,790 — Deposit instruments (*2) 60,542 35,040 ￦ 1,911,684 1,647,898 (*1) As of December 31, 2017 and 2018, ￦ ￦ (*2) As of December 31, 2017 and 2018, financial instruments amounting to ￦ ￦ (*3) As of December 31, 2017 and 2018, ￦ ￦
Trade accounts and notes receivables, net [member]
Statement [LineItems]
Summary of Financial Assets	(a) Trade accounts and notes receivable as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Trade accounts and notes receivable ￦ 8,579,620 8,648,250 Finance lease receivables 10,469 57,487 Unbilled due from customers for contract work 728,007 810,655 Less: Allowance for doubtful accounts (493,533 ) (386,188 ) ￦ 8,824,563 9,130,204 Non-current Trade accounts and notes receivable ￦ 871,432 583,797 Finance lease receivables 734 45,873 Less: Allowance for doubtful accounts (140,596 ) (202,545 ) ￦ 731,570 427,125
Finance lease receivables [member]
Statement [LineItems]
Summary of Financial Assets	(b) Finance lease receivables are as follows: Customer Contents 2017 2018 (in millions of Won) Rental contractor (executives and employees) Songdo rental apartment contract ￦ — 103,360 Korea Electric Power Corporation Combined thermal power plant #3~4 10,469 — Hystech.Co. Ltd. Machinery and equipment 734 — ￦ 11,203 103,360

Trade Accounts and Notes Rece_2

Trade Accounts and Notes Receivable (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Gross Amount and Present Value of Minimum Lease Payments	(c) The gross amount and present value of minimum lease payments as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Less than 1 year ￦ 11,771 57,820 1 year – 5 years 828 49,678 Unrealized interest income (1,396 ) (4,138 ) Present value of minimum lease payment ￦ 11,203 103,360

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Inventories	Inventories as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Finished goods ￦ 1,526,628 1,886,040 Merchandise 930,558 1,131,416 Semi-finished goods 1,721,130 1,945,567 Raw materials 2,329,268 2,821,972 Fuel and materials 808,016 888,941 Construction inventories 1,692,092 1,372,259 Materials-in-transit 1,818,576 2,245,740 Others 103,144 68,150 10,929,412 12,360,085 Less: Allowance for inventories valuation (135,631 ) (206,782 ) ￦ 10,793,781 12,153,303
Changes of Allowance for Inventories Valuation	The changes of allowance for inventories valuation for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Beginning ￦ 231,378 203,164 135,631 Loss on valuation of inventories 152,249 78,560 141,799 Realization on disposal of inventories (161,458 ) (138,967 ) (69,426 ) Others (19,005 ) (7,126 ) (1,222 ) Ending ￦ 203,164 135,631 206,782

Assets Held for Sale (Tables)

Assets Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Details of Assets Held For Sale and Related Liabilities	Details of assets held for sale as of December 31, 2017 and 2018 are as follows: 2017 2018 Controlling Subsidiaries (*1) Total Subsidiaries (*2) (in millions of Won) Assets Other financial assets ￦ — — — 778 Property, plant and equipment 392 71,340 71,732 21,076 Others — 36 36 — ￦ 392 71,376 71,768 21,854 (*1) During the year ended December 2017, POSCO ENGINEERING & CONSTRUCTION CO., LTD., a subsidiary of the Company, determined to dispose of the office building, Seomyeon Fiesta, in Busan and classified the related property, plant and equipment amounting to ￦ (*2) During the year ended December 31, 2018, DAESAN (CAMBODIA) Co., Ltd., a subsidiary of the Company, determined to dispose of the land and classified the related property, plant and equipment amounting to ￦

Investments in Associates and_2

Investments in Associates and Joint ventures (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Investments in Associates and Joint Ventures	Investments in associates and joint ventures as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Investments in associates ￦ 1,520,441 1,738,692 Investments in joint ventures 2,037,491 1,911,311 ￦ 3,557,932 3,650,003
Details of Investments in Associates	Details of investments in associates as of December 31, 2017 and 2018 are as follows: Number of shares Ownership (%) Acquisition cost Book value Company 2017 2018 (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources 178,713,975,892 31.27 ￦ 178,787 ￦ 175,553 174,123 POSPower Co., Ltd (*1,2) 4,507,138 34.00 164,757 — 161,477 SNNC 18,130,000 49.00 90,650 110,424 116,922 QSONE Co., Ltd. 200,000 50.00 84,395 85,049 85,550 Chun-cheon Energy Co., Ltd (*2) 16,098,143 45.67 80,491 74,378 62,478 CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd 2,008,000 29.53 10,040 17,252 17,382 Daesung Steel (*4) 108,038 17.54 14,000 15,500 15,644 Incheon-Gimpo Expressway Co., Ltd. (*2,4) 9,032,539 18.26 45,163 31,660 13,329 Keystone NO. 1. Private Equity Fund 13,800,000 40.45 13,800 12,379 11,183 KoFC POSCO HANWHA KB Shared Growth (*4) 6,485 12.50 6,485 6,828 5,739 KONES, Corp. 3,250,000 41.67 6,893 2,827 2,849 BLUE OCEAN Private Equity Fund 333 27.52 33,300 19,620 — UITrans LRT Co., Ltd. (*2) 7,714,380 38.19 38,572 15,841 — Others (46 companies) (*2) 67,325 123,734 634,636 790,410 [Foreign] AES-VCM (*3) — 30.00 164,303 142,348 209,936 South-East Asia Gas Pipeline Company Ltd. 135,219,000 25.04 135,899 197,069 179,459 7623704 Canada Inc. (*4) 114,452,000 10.40 124,341 121,702 126,885 Eureka Moly LLC — 20.00 240,123 79,398 82,447 AMCI (WA) PTY LTD 49 49.00 209,664 63,378 71,086 KOREA LNG LTD. 2,400 20.00 135,205 33,422 43,554 Nickel Mining Company SAS 3,234,698 49.00 157,585 45,905 41,712 NCR LLC — 29.41 40,139 33,738 37,602 PT. Batutua Tembaga Raya 128,285 22.00 21,824 21,823 20,479 Zhongyue POSCO (Qinhuangdao) Tinplate 10,200,000 34.00 9,517 15,617 14,796 PT. Wampu Electric Power (*2) 8,708,400 20.00 10,054 13,391 14,120 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 50 25.00 4,723 6,517 6,478 Others (29 companies) (*2) 111,497 99,728 885,805 948,282 ￦ 1,520,441 1,738,692 (*1) During the year ended December 31, 2018, the Company disposed of 63.53% of shares in POSPower Co., Ltd, which resulted in the Company’s loss of control, and the Company classified the remaining investment as investment in an associate. (*2) As of December 31, 2017 and 2018, investments in associates amounting to ￦ ￦ (*3) As of December 31, 2017 and 2018, shares of PSC Energy Global Co., Ltd., a subsidiary of the Company, are provided as collateral in relation to the associates’ borrowings. (*4) As of December 31, 2018, it was classified as an associate even though the Company’s ownership percentage is less than 20% of ownership percentage since the Company has significant influence over the investee when considering its structure of the Board of Directors and others.
Details of Investments in Joint Ventures	Details of investments in joint ventures as of December 31, 2017 and 2018 are as follows: Number of shares Ownership (%) Acquisition cost Book value Company 2017 2018 (in millions of Won) [Domestic] POSCO MITSUBISHI CARBON TECHNOLOGY 11,568,000 60.00 ￦ 115,680 ￦ 110,760 180,192 Others (6 companies) 6,094 9,124 116,854 189,316 [Foreign] Roy Hill Holdings Pty Ltd (*1) 13,117,972 12.50 1,528,672 1,125,133 1,041,600 POSCO-NPS 325,050,000 50.00 364,609 348,836 363,506 KOBRASCO 2,010,719,185 50.00 32,950 108,485 133,449 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — 25.00 61,961 88,305 88,391 DMSA/AMSA (*1) — 4.00 322,596 56,735 26,709 CSP — Compania Siderurgica do Pecem 1,108,696,532 20.00 558,821 146,427 24,832 Others (13 companies) 46,716 43,508 1,920,637 1,721,995 ￦ 2,037,491 1,911,311 (*1) As of December 31, 2017 and 2018, the investments in joint ventures are provided as collateral in relation to the joint ventures’ borrowings.
Movements of Investments in Associates and Joint Ventures	The movements of investments in associates and joint ventures for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Company December 31, Book value Acquisition Dividends Share of Other (decrease) (*1) December 31, Book value (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources Private Equity Fund ￦ 175,690 — — 418 (555 ) 175,553 SNNC 107,859 — — 2,370 195 110,424 QSONE Co., Ltd. 84,799 — (368 ) 618 — 85,049 Chun-cheon Energy Co., Ltd 45,077 27,791 — 1,510 — 74,378 CHUNGJU ENTERPRISE CITY DEVELOPMENT Co., Ltd 12,551 — — 4,701 — 17,252 BLUE OCEAN Private Equity Fund 35,752 — — (8,154 ) (7,978 ) 19,620 Daesung Steel 12,302 — — 3,198 — 15,500 Incheon-Gimpo Expressway Co., Ltd. 37,372 — — (6,463 ) 751 31,660 Keystone NO. 1. Private Equity Fund 13,314 — — (886 ) (49 ) 12,379 UITrans LRT Co., Ltd. 17,851 — — (2,010 ) — 15,841 KoFC POSCO HANWHA KB Shared Growth 11,890 — — (197 ) (4,865 ) 6,828 KONES, Corp. 5,641 — — (2,774 ) (40 ) 2,827 POSCO MITSUBISHI CARBON TECHNOLOGY 83,113 — — 27,582 65 110,760 Others (40 companies) 55,061 28,348 (137 ) (7,995 ) (1,858 ) 73,419 698,272 56,139 (505 ) 11,918 (14,334 ) 751,490 [Foreign] AES-VCM 167,141 — (30,798 ) 19,644 (13,639 ) 142,348 South-East Asia Gas Pipeline Company Ltd. 215,996 — (37,016 ) 42,896 (24,807 ) 197,069 7623704 Canada Inc. 137,512 — (7,563 ) 7,468 (15,715 ) 121,702 Eureka Moly LLC 89,601 — — (35 ) (10,168 ) 79,398 AMCI (WA) PTY LTD 70,501 — — (4,299 ) (2,824 ) 63,378 Nickel Mining Company SAS 45,138 — — 424 343 45,905 KOREA LNG LTD. 63,058 — (6,466 ) (70,180 ) 47,010 33,422 NCR LLC 36,738 276 — (60 ) (3,216 ) 33,738 PT. Batutua Tembaga Raya 22,723 — — 260 (1,160 ) 21,823 PT. Wampu Electric Power 8,706 — — 5,927 (1,242 ) 13,391 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 18,008 — — (1,268 ) (1,123 ) 15,617 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,840 — — 303 (626 ) 6,517 Roy Hill Holdings Pty Ltd 1,186,859 — — 46,020 (107,746 ) 1,125,133 POSCO-NPS 393,570 — (17,277 ) 17,173 (44,630 ) 348,836 KOBRASCO 88,308 — (22,135 ) 56,445 (14,133 ) 108,485 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 97,369 — (5,542 ) 1,555 (5,077 ) 88,305 DMSA/AMSA 74,935 13,712 — (22,339 ) (9,573 ) 56,735 CSP - Compania Siderurgica do Pecem 330,463 — — (147,847 ) (36,189 ) 146,427 Others (40 companies) 130,651 22,209 (4,408 ) 46,535 (36,774 ) 158,213 3,184,117 36,197 (131,205 ) (1,378 ) (281,289 ) 2,806,442 ￦ 3,882,389 92,336 (131,710 ) 10,540 (295,623 ) 3,557,932 (*1) Other increase or decrease represents the changes in investments in associates and joint ventures due to disposals, change in capital adjustments effect from translations of financial statements of foreign investees and others. 2) For the year ended December 31, 2018 Company December 31, Acquisition Dividends Share of Other (*1) December 31, (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 175,553 — — (1,430 ) — 174,123 POSPower Co., Ltd — 176,731 — (3,198 ) (12,056 ) 161,477 SNNC 110,424 — — 6,624 (126 ) 116,922 QSONE Co., Ltd. 85,049 — (550 ) 1,051 — 85,550 Chun-cheon Energy Co., Ltd 74,378 — — (11,900 ) — 62,478 CHUNGJU ENTERPRISE CITY 17,252 — — 130 — 17,382 BLUE OCEAN Private Equity Fund 19,620 — — (17,930 ) (1,690 ) — Daesung Steel 15,500 — — 144 — 15,644 Incheon-Gimpo Expressway Co., Ltd. 31,660 — — (18,331 ) — 13,329 Keystone NO. 1. Private Equity Fund 12,379 — — (1,295 ) 99 11,183 UITrans LRT Co., Ltd. 15,841 — — (15,841 ) — — KoFC POSCO HANWHA KB Shared Growth 6,828 — — (1,089 ) — 5,739 KONES, Corp. 2,827 — — 29 (7 ) 2,849 POSCO MITSUBISHI CARBON TECHNOLOGY 110,760 — — 69,594 (162 ) 180,192 Others (52 companies) 73,419 44,629 (784 ) 18,942 (3,348 ) 132,858 751,490 221,360 (1,334 ) 25,500 (17,290 ) 979,726 [Foreign] AES-VCM 142,348 — (26,108 ) 30,096 63,600 209,936 South-East Asia Gas Pipeline Company Ltd. 197,069 — (29,301 ) 17,709 (6,018 ) 179,459 7623704 Canada Inc. 121,702 — (4,509 ) 4,373 5,319 126,885 Eureka Moly LLC 79,398 — — (406 ) 3,455 82,447 AMCI (WA) PTY LTD. 63,378 — — (3,412 ) 11,120 71,086 KOREA LNG LTD. 33,422 — (10,544 ) 10,542 10,134 43,554 Nickel Mining Company SAS 45,905 — — (4,268 ) 75 41,712 NCR LLC 33,738 2,505 — (5,909 ) 7,268 37,602 PT. Batutua Tembaga Raya 21,823 — — (1,817 ) 473 20,479 Zhongyue POSCO (Qinhuangdao) Tinplate 15,617 — — (735 ) (86 ) 14,796 PT. Wampu Electric Power 13,391 — — 177 552 14,120 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,517 — — 23 (62 ) 6,478 Roy Hill Holdings Pty Ltd 1,125,133 — — 59,095 (142,628 ) 1,041,600 POSCO-NPS 348,836 — (22,254 ) 21,536 15,388 363,506 KOBRASCO 108,485 — (37,710 ) 75,170 (12,496 ) 133,449 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 88,305 — — 540 (454 ) 88,391 DMSA/AMSA 56,735 17,973 — (48,802 ) 803 26,709 CSP - Compania Siderurgica do Pecem 146,427 — — (109,714 ) (11,881 ) 24,832 Others (42 companies) 158,213 2,771 (22,588 ) 42,937 (38,097 ) 143,236 2,806,442 23,249 (153,014 ) 87,135 (93,535 ) 2,670,277 ￦ 3,557,932 244,609 (154,348 ) 112,635 (110,825 ) 3,650,003 (*1) Other increase or decrease represents the changes in investments in associates and joint ventures due to disposals, change in capital adjustments effect from translations of financial statements of foreign investees and others.
Summarized Financial Information of Associates and Joint Ventures	Summarized financial information of associates and joint ventures as of and for the years ended December 31, 2017 and 2018 are as follows: 1) December 31, 2017 Company Assets Liabilities Equity Sales Net (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 562,698 866 561,832 — 1,261 SNNC 705,975 459,519 246,456 576,023 2,417 QSONE Co., Ltd. 248,779 78,680 170,099 15,297 1,236 Chun-cheon Energy Co., Ltd 700,079 539,137 160,942 164,294 (8,250 ) Daesung Steel 169,774 112,795 56,979 70,434 18,230 Incheon-Gimpo Expressway Co., Ltd. 1,132,233 922,338 209,895 — (23,221 ) CHUNGJU ENTERPRISE CITY 76,184 48,072 28,112 77,093 15,921 BLUE OCEAN Private Equity Fund 311,129 188,512 122,617 445,238 (3,345 ) Keystone NO. 1. Private Equity Fund 170,155 133,033 37,122 5,391 (2,070 ) UITrans LRT Co., Ltd. 464,074 384,202 79,872 3,689 (13,263 ) KoFC POSCO HANWHA KB Shared Growth 55,936 1,315 54,621 10,212 (1,578 ) KONES, Corp. 2,766 1,616 1,150 5,379 139 POSCO MITSUBISHI CARBON TECHNOLOGY 478,847 295,052 183,795 154,312 46,138 [Foreign] South-East Asia Gas Pipeline Company Ltd. 1,911,942 1,121,783 790,159 445,682 171,303 7623704 Canada Inc. 1,182,376 9 1,182,367 — 82,344 KOREA LNG LTD. 179,269 86 179,183 34,640 32,446 Nickel Mining Company SAS 465,700 324,687 141,013 179,683 (4,450 ) PT. Batutua Tembaga Raya 336,085 272,542 63,543 195,520 49,091 Zhongyue POSCO (Qinhuangdao) Tinplate 70,437 18,722 51,715 85,850 (3,736 ) PT. Wampu Electric Power 212,095 148,177 63,918 779 29,634 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 70,701 43,588 27,113 84,973 1,210 Roy Hill Holdings Pty Ltd 10,148,416 6,600,900 3,547,516 2,988,372 797,008 POSCO-NPS 697,470 — 697,470 — 32,481 KOBRASCO 252,813 35,843 216,970 179,453 112,890 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 717,472 391,871 325,601 1,245,178 5,978 DMSA/AMSA 5,586,171 4,167,906 1,418,265 630,229 (475,958 ) CSP - Compania Siderurgica do Pecem 4,805,353 4,223,392 581,961 1,290,767 (740,591 ) 2) December 31, 2018 Company Assets Liabilities Equity Sales Net (in millions of Won) [Domestic] EQP POSCO Global NO1 Natural Resources ￦ 552,760 783 551,977 — 10,249 POSPower Co., Ltd 425,632 35,761 389,871 — (4,536 ) SNNC 645,013 384,586 260,427 656,320 14,229 QSONE Co., Ltd. 249,384 78,285 171,099 16,597 2,101 Chun-cheon Energy Co., Ltd 667,454 525,308 142,146 320,950 (18,796 ) CHUNGJU ENTERPRISE CITY 63,554 35,003 28,551 16,237 439 BLUE OCEAN Private Equity Fund 305,876 174,640 131,236 459,491 (5,294 ) Daesung Steel 169,305 111,502 57,803 75,474 824 Incheon-Gimpo Expressway Co., Ltd. 1,049,629 931,937 117,692 — (92,202 ) Keystone NO. 1. Private Equity Fund 177,024 144,186 32,838 15,507 (3,962 ) UITrans LRT Co., Ltd. 430,227 435,699 (5,472 ) 12,929 (85,344 ) KoFC POSCO HANWHA KB Shared Growth 59,464 1,061 58,403 2,401 (12,313 ) KONES, Corp. 2,618 1,414 1,204 5,167 70 POSCO MITSUBISHI CARBON TECHNOLOGY 537,138 237,563 299,575 300,986 116,049 [Foreign] South-East Asia Gas Pipeline Company Ltd. 1,726,410 1,009,731 716,679 343,471 70,717 7623704 Canada Inc. 1,232,208 1 1,232,207 — 44,320 KOREA LNG LTD. 217,883 110 217,773 54,357 52,720 Nickel Mining Company SAS 465,463 329,084 136,379 207,956 (4,569 ) PT. Batutua Tembaga Raya 332,305 274,580 57,725 128,609 (8,451 ) Zhongyue POSCO (Qinhuangdao) Tinplate 73,515 24,264 49,251 121,104 (2,231 ) PT. Wampu Electric Power 223,009 155,407 67,602 13,461 887 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 61,782 34,740 27,042 85,619 78 Roy Hill Holdings Pty Ltd 9,666,619 6,043,492 3,623,127 3,259,256 497,469 POSCO-NPS 726,810 — 726,810 — 41,812 KOBRASCO 317,842 50,945 266,897 229,340 150,550 BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 710,518 384,572 325,946 1,341,849 2,159 DMSA/AMSA 5,562,877 4,171,896 1,390,981 731,127 (529,844 ) CSP - Compania Siderurgica do Pecem 4,194,242 4,192,867 1,375 1,860,198 (542,865 )

Joint Operations (Tables)

Joint Operations (Tables)	12 Months Ended
	Dec. 31, 2018
Investments accounted for using equity method [abstract]
Details of Significant Joint Operations	Details of significant joint operations that the Company is participating in as a party to a joint arrangement as of December 31, 2018 are as follows: Joint operations Operation Ownership Location Myanmar A-1/A-3 Mineral development and gas production 51.00 Myanmar Offshore midstream Gas transportation facility 51.00 Myanmar Greenhills mine Mine development 20.00 Canada Arctos Anthracite coal project Mine development 50.00 Canada Mt. Thorley J/V Mine development 20.00 Australia POSMAC J/V Mine development 20.00 Australia RUM J/V Mine development 10.00 Australia Hanam-Gamil package public housing project Construction 7.70 Korea Hanam-Gamil district B6, C2, C3 block Public Construction 27.00 Korea Sejong 2-1 Construction 37.00 Korea Yongin-Giheung Station area city development project Construction 61.00 Korea Korean wave world complex land multi-purpose building development project Construction 33.30 Korea Sejong 4-1 Construction 60.00 Korea

Investment Property, Net (Table

Investment Property, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Investment Property	Investment property as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition cost Accumulated depreciation and impairment loss Book value Acquisition cost Accumulated depreciation and impairment loss Book value (in millions of Won) Land ￦ 360,402 — 360,402 295,328 (16,743 ) 278,585 Buildings 727,022 (92,982 ) 634,040 681,518 (110,183 ) 571,335 Structures 7,717 (1,436 ) 6,281 3,327 (1,919 ) 1,408 Construction-in-progress 64,191 — 64,191 101,665 (24,378 ) 77,287 ￦ 1,159,332 (94,418 ) 1,064,914 1,081,838 (153,223 ) 928,615
Changes in Carrying Amount of Investment Property	Changes in the carrying amount of investment property for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Disposals Depreciation Others (*1) Ending (in millions of Won) Land ￦ 392,723 20,941 (37,725 ) — (15,537 ) 360,402 Buildings 671,539 38,831 (9,506 ) (23,450 ) (43,374 ) 634,040 Structures 2,147 — — (591 ) 4,725 6,281 Construction-in-progress 51,311 17,648 — — (4,768 ) 64,191 ￦ 1,117,720 77,420 (47,231 ) (24,041 ) (58,954 ) 1,064,914 (*1) Includes reclassification resulting from changing purpose of use, adjustment of foreign currency translation difference and others. 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Depreciation (*1) Others (*2) Ending (in millions of Won) Land ￦ 360,402 1,327 (26,826 ) (16,743 ) (39,575 ) 278,585 Buildings 634,040 727 (32,807 ) (28,358 ) (2,267 ) 571,335 Structures 6,281 — — (603 ) (4,270 ) 1,408 Construction-in-progress 64,191 42,052 — (24,948 ) (4,008 ) 77,287 ￦ 1,064,914 44,106 (59,633 ) (70,652 ) (50,120 ) 928,615 (*1) Includes impairment loss on investment property recognized by each of the consolidated subsidiaries, including the office for rent of POSCO(Dalian) IT Center Development Co., Ltd. amounting to ￦ (*2) Includes reclassification resulting from changing purpose of use, adjustment of foreign currency translation difference and others.

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition Accumulated Government Book value Acquisition cost Accumulated loss Government grants Book value (in millions of Won) Land ￦ 2,534,102 (6,452 ) — 2,527,650 2,553,957 (5,955 ) — 2,548,002 Buildings 9,311,426 (4,433,996 ) (412 ) 4,877,018 9,146,294 (4,743,449 ) (393 ) 4,402,452 Structures 5,452,713 (2,686,802 ) (59 ) 2,765,852 5,884,277 (2,966,304 ) (49 ) 2,917,924 Machinery and equipment 46,669,612 (27,301,410 ) (245 ) 19,367,957 47,610,225 (29,091,754 ) (342 ) 18,518,129 Vehicles 296,815 (263,884 ) (70 ) 32,861 302,767 (271,381 ) (45 ) 31,341 Tools 380,144 (315,446 ) (1,058 ) 63,640 399,638 (333,387 ) (87 ) 66,164 Furniture and fixtures 643,779 (498,192 ) (148 ) 145,439 638,553 (502,215 ) (51 ) 136,287 Finance lease assets 243,160 (97,903 ) — 145,257 213,873 (76,309 ) — 137,564 Bearer plants 70,031 (4,516 ) — 65,515 88,773 (8,002 ) — 80,771 Construction-in- 1,897,885 — (5,539 ) 1,892,346 1,964,267 (778,373 ) (6,255 ) 1,179,639 ￦ 67,499,667 (35,608,601 ) (7,531 ) 31,883,535 68,802,624 (38,777,129 ) (7,222 ) 30,018,273
Changes in Carrying Amount of Property, Plant and Equipment	Changes in the carrying amount of property, plant and equipment for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Disposals Depreciation Impairment (*1) Others (*2) Ending (in millions of Won) Land ￦ 2,601,208 3,477 (18,226 ) — — (58,809 ) 2,527,650 Buildings 4,995,631 53,961 (5,782 ) (347,419 ) (14,112 ) 194,739 4,877,018 Structures 2,908,480 18,943 (2,558 ) (212,643 ) (33,586 ) 87,216 2,765,852 Machinery and equipment 20,318,390 194,653 (93,210 ) (2,189,624 ) (27,811 ) 1,165,559 19,367,957 Vehicles 46,699 9,982 (1,623 ) (17,363 ) (4,977 ) 143 32,861 Tools 71,380 16,424 (976 ) (28,516 ) (23 ) 5,351 63,640 Furniture and fixtures 132,406 61,597 (1,296 ) (48,400 ) (16 ) 1,148 145,439 Finance lease assets 159,013 4,760 (453 ) (14,810 ) — (3,253 ) 145,257 Bearer plants — — — (4,830 ) — 70,345 65,515 Construction-in- 2,537,132 1,894,067 (817 ) — (36,706 ) (2,501,330 ) 1,892,346 ￦ 33,770,339 2,257,864 (124,941 ) (2,863,605 ) (117,231 ) (1,038,891 ) 31,883,535 (*1) As of December 31, 2017, due to the existence of indicators for impairment such as continuous operating loss on Suncheon Bay Personal Rapid Transit business of the Suncheon Eco Trans Co., Ltd, a subsidiary of the Company, the Company performed impairment test and recognized impairment loss of ￦ ￦ (*2) Represents assets transferred from construction-in-progress 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Depreciation Impairment (*1,2) Others (*3) Ending (in millions of Won) Land ￦ 2,527,650 28,998 (26,157 ) — 6,399 11,112 2,548,002 Buildings 4,877,018 46,129 (21,501 ) (331,688 ) (73,523 ) (93,983 ) 4,402,452 Structures 2,765,852 18,749 (2,834 ) (220,218 ) (6,652 ) 363,027 2,917,924 Machinery and equipment 19,367,957 145,220 (62,135 ) (2,224,000 ) (143,293 ) 1,434,380 18,518,129 Vehicles 32,861 8,538 (1,149 ) (14,835 ) (56 ) 5,982 31,341 Tools 63,640 21,337 (1,867 ) (26,421 ) (206 ) 9,681 66,164 Furniture and fixtures 145,439 32,258 (577 ) (51,835 ) (1,494 ) 12,496 136,287 Finance lease assets 145,257 28,466 (420 ) (19,224 ) — (16,515 ) 137,564 Bearer plants 65,515 — — (3,636 ) — 18,892 80,771 Construction-in-progress 1,892,346 1,884,125 (23,814 ) — (778,373 ) (1,794,645 ) 1,179,639 ￦ 31,883,535 2,213,820 (140,454 ) (2,891,857 ) (997,198 ) (49,573 ) 30,018,273 (*1) During 2018, the Controlling Company evaluated future economic performance of its Synthetic Natural Gas (SNG) facility that was still in trial run stage. Considering the continuous decline in LNG price, increase in coal prices and the need for additional capital investment in the SNG facility, the Controlling Company concluded that the profitability for the SNG facility is unlikely to be sustainable and decided to terminate the operation of SNG facility as of December 31, 2018. The property, plant and equipment in the SNG facility are primarily comprised of machinery and equipment, among which assets with a carrying value of ￦ re-used
Borrowing Costs Capitalized and Capitalized Interest Rate	Borrowing costs capitalized and the capitalized interest rate for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Weighted average expenditure ￦ 1,180,563 628,595 Borrowing costs capitalized 37,261 22,619 Capitalization rate (%) 1.74 ~ 3.45 2.51 ~ 3.90
Property, Plant and Equipment and Investment Property Pledged as Collateral	Property, plant and equipment and investment property pledged as collateral as of December 31, 2017 and 2018 are as follows: Book value Collateral right holder 2017 2018 (*2) (in millions of Won) Land (*1) Korean Development Bank and others ￦ 822,057 769,843 Buildings and structures (*1) Korean Development Bank and others 1,678,403 1,522,129 Machinery and equipment Korean Development Bank and others 3,527,420 3,419,528 Construction-in-progress Korean Development Bank and others 15,389 — ￦ 6,043,269 5,711,500 (*1) Investment property and other assets (land-use (*2) As of December 31, 2018, the pledged amount is ￦

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Goodwill and Other Intangible Assets	Goodwill and other intangible assets as of December 31, 2017 and 2018 are as follows: 2017 2018 Acquisition Accumulated Government Book value Acquisition Accumulated Government Book value (in millions of Won) Goodwill ￦ 1,604,288 (254,450 ) — 1,349,838 1,603,308 (478,159 ) — 1,125,149 Intellectual property rights 3,140,159 (690,966 ) — 2,449,193 3,300,638 (901,113 ) — 2,399,525 Premium in rental 139,873 (21,563 ) — 118,310 158,338 (23,545 ) — 134,793 Development expense 397,129 (316,892 ) (19 ) 80,218 445,752 (346,589 ) — 99,163 Port facilities usage rights 705,692 (396,319 ) — 309,373 724,375 (419,294 ) — 305,081 Exploration and evaluation assets 296,320 (90,376 ) — 205,944 285,845 (93,715 ) — 192,130 Customer relationships 857,624 (390,679 ) — 466,945 860,951 (439,178 ) — 421,773 Power generation permit 539,405 — — 539,405 — — — — Other intangible assets 1,006,219 (573,152 ) (24 ) 433,043 1,115,742 (622,417 ) (114 ) 493,211 ￦ 8,686,709 (2,734,397 ) (43 ) 5,952,269 8,494,949 (3,324,010 ) (114 ) 5,170,825
Changes in Carrying Amount of Goodwill and Other Intangible Assets	The changes in carrying amount of goodwill and other intangible assets for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Acquisitions Business Disposals Amortization Impairment Others (*2) Ending (in millions of Won) Goodwill ￦ 1,375,131 — — — — (21,750 ) (3,543 ) 1,349,838 Intellectual property rights 2,521,171 167,580 47,625 (450 ) (217,932 ) (74,524 ) 5,723 2,449,193 Premium in rental (*1) 119,039 6,006 — (3,666 ) (611 ) (1,661 ) (797 ) 118,310 Development expense 117,012 3,479 — (1,179 ) (66,847 ) (694 ) 28,447 80,218 Port facilities usage rights 256,617 — — — (19,912 ) — 72,668 309,373 Exploration and evaluation assets 162,268 91,548 — — — (56,519 ) 8,647 205,944 Customer relationships 514,245 — — — (46,508 ) — (792 ) 466,945 Power generation permit 539,405 — — — — — — 539,405 Other intangible assets 483,841 84,502 — (1,641 ) (57,964 ) (11,829 ) (63,866 ) 433,043 ￦ 6,088,729 353,115 47,625 (6,936 ) (409,774 ) (166,977 ) 46,487 5,952,269 (*1) Premium in rental includes memberships with indefinite useful lives. (*2) Represents assets transferred from construction-in-progress 2) For the year ended December 31, 2018 Beginning Acquisitions Disposals Amortization Impairment Others (*3) Ending (in millions of Won) Goodwill ￦ 1,349,838 — — — (223,709 ) (980 ) 1,125,149 Intellectual property rights 2,449,193 334,667 (18,619 ) (198,282 ) (96,475 ) (70,959 ) 2,399,525 Premium in rental (*1) 118,310 36,196 (15,675 ) (330 ) (4,218 ) 510 134,793 Development expense 80,218 4,248 (32 ) (37,305 ) (411 ) 52,445 99,163 Port facilities usage rights 309,373 — — (22,975 ) — 18,683 305,081 Exploration and evaluation assets 205,944 2,654 — — (3,339 ) (13,129 ) 192,130 Customer relationships 466,945 — — (48,499 ) — 3,327 421,773 Power generation permit 539,405 — — — — (539,405 ) — Other intangible assets 433,043 164,594 (1,644 ) (49,190 ) (8,844 ) (44,748 ) 493,211 ￦ 5,952,269 542,359 (35,970 ) (356,581 ) (336,996 ) (594,256 ) 5,170,825 (*1) Premium in rental includes memberships with indefinite useful lives. (*2) During the year ended December 31, 2018, the Company disposed of a portion of shares of its subsidiary, POSPower Co., Ltd, which resulted in the Company’s loss of control, and derecognition of corresponding intangible assets. (*3) Represents assets transferred from construction-in-progress
Allocation of Goodwill to Individually Operating Entities Which are Determined to be CGUs	For the purpose of impairment testing, goodwill is allocated to individually operating entities which are determined to be CGUs. The goodwill amounts as of December 31, 2017 and 2018 are as follows: Reportable segments Total number of CGUs 2017 2018 CGUs 2017 2018 (in millions of Won) Steel 7 7 POSCO VST CO., LTD. ￦ 36,955 36,955 Others 12,494 12,484 Trading 2 2 POSCO DAEWOO Corporation (*1) 1,165,030 1,006,879 PT. Bio Inti Agrindo 7,099 6,902 Others — 16 E&C 2 2 POSCO ENGINEERING (*2) 90,426 24,868 POSCO Center Beijing 157 155 POSCO ENERGY CO., LTD. 26,471 26,471 Others 5 5 Others 11,206 10,419 16 16 ￦ 1,349,838 1,125,149 (*1) Recoverable amounts of POSCO DAEWOO Corporation are determined based on its value in use. As of December 31, 2018, value in use is estimated by applying a 7.84% discount rate and a 2.0% terminal growth rate after 5 years, based on management’s business plan. The terminal growth rate does not exceed long-term average growth rate of its industry. Impairment loss on goodwill of ￦ Value in use of the CGU was affected by the assumptions such as discount rate and terminal growth used in discount cash flow model. When the discount rate increases by 0.25%, value in use will be decreased by ￦ ￦ (*2) Recoverable amounts of POSCO ENGINEERING & CONSTRUCTION CO., LTD are determined based on its value in use. As of December 31, 2018, value in use is estimated by applying a 9.1% discount rate within 5 years, the period for the estimated future cash flows, based on management’s business plan and by no applying a terminal growth rate. Impairment loss on goodwill of ￦ Value in use of the CGU was affected by the assumptions such as discount rate and terminal growth used in discount cash flow model. When the discount rate increases by 0.25%, value in use will be decreased by 2.72% and when the terminal growth rate decreases by 0.25%, value in use will be decreased by 1.76%.

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Other Current Assets and Other Non-Current Assets	Other current assets and other non-current 2017 2018 (in millions of Won) Current Advance payment ￦ 661,779 539,894 Prepaid expenses 143,032 123,770 Firm commitment asset 15,115 11,246 Others 1,316 9,554 821,242 684,464 Non-current Long-term advance payment 24,201 24,280 Long-term prepaid expenses 333,153 334,918 Others (*1) 131,657 149,566 ￦ 489,011 508,764 (*1) As of December 31, 2017 and 2018, the Company recognized tax assets amounting to ￦ ￦

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Summary of Assets Pledges as Collateral	Assets pledged as collateral in regards to the borrowings as of December 31, 2018 are as follows: Bank Book value Pledged (in millions of Won) Cash and cash equivalents Shinhan Bank ￦ 8,296 8,296 Property, plant and equipment and Investment (*1) Korea Development Bank and others 5,592,627 5,304,861 Trade accounts and notes receivable Korea Development Bank and others 157,617 157,617 Inventories Export-Import Bank of Korea and others 205,433 163,233 Financial instruments Kookmin Bank and others 40,664 40,664 ￦ 6,004,637 5,674,671 (*1) Includes other assets such as right to use land.
Short-term borrowings and current portion of long-term borrowings [member]
Statement [LineItems]
Summary of Borrowings	Short-term borrowings and current portion of long-term borrowings as of December 31, 2017 and 2018 are as follows: Bank Issuance date Maturity date Interest 2017 2018 (in millions of Won) Short-term borrowings Bank overdrafts JP Morgan and January, 2017~ January, 2019~ 2.7~8.9 ￦ 217,879 294,364 Short-term borrowings HSBC and others January, 2018~ January, 2019~ 0.3~10.1 7,956,939 7,193,416 8,174,818 7,487,780 Current portion of long-term liabilities Current portion of long-term borrowings Export-Import bank of Korea and others September, 2011~ February, 2019~ 0.5~8.8 1,407,123 1,234,915 Current portion of debentures Korea Development August, 2009~ February, 2019~ 1.8~6.3 1,693,974 1,568,108 Less: Current portion of discount on debentures issued (1,399 ) (1,184 ) 3,099,698 2,801,839 ￦ 11,274,516 10,289,619
Long-term borrowings [member]
Statement [LineItems]
Summary of Borrowings	Long-term borrowings, excluding current portion as of December 31, 2017 and 2018 are as follows: Bank Issuance date Maturity date Interest 2017 2018 (in millions of Won) Long-term borrowings Export-Import bank of Korea and others September, 2001~ March, 2020~ 0.2~8.8 ￦ 4,839,199 4,499,199 Less: Present value discount (36,459 ) (30,526 ) Bonds KB Securities and others October, 2010~ April, 2020~ 1.9~5.3 4,999,575 5,469,580 Less: Discount on debentures issued (13,174 ) (18,602 ) ￦ 9,789,141 9,919,651

Other Payables (Tables)

Other Payables (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Summary of Financial Liabilities	Other financial liabilities as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Derivatives liabilities ￦ 69,872 27,328 Financial guarantee liabilities 59,940 50,472 ￦ 129,812 77,800 Non-current Derivatives liabilities ￦ 85,638 46,429 Financial guarantee liabilities 28,467 17,733 ￦ 114,105 64,162
Other payables [member]
Statement [LineItems]
Summary of Financial Liabilities	Other payables as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Accounts payable ￦ 800,374 783,562 Accrued expenses 653,923 720,773 Dividend payable 7,213 8,673 Finance lease liabilities 17,763 10,152 Withholdings 274,188 196,937 ￦ 1,753,461 1,720,097 Non-current Accounts payable ￦ 4,632 1,624 Accrued expenses 14,234 19,021 Finance lease liabilities 75,255 84,602 Long-term withholdings 53,629 43,621 ￦ 147,750 148,868

Provisions (Tables)

Provisions (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Provisions	Provisions as of December 31, 2017 and 2018 are as follows: 2017 2018 Current Non-current Current Non-current (in millions of Won) Provision for bonus payments ￦ — 46,514 26,964 Provision for construction warranties 11,804 106,232 11,842 130,391 Provision for legal contingencies and claims (*1) 495 36,269 16,981 55,716 Provision for the restoration (*2) 12,273 121,917 9,379 79,789 Others (*3,4) 37,203 212,754 213,737 138,176 ￦ 477,172 298,453 431,036 (*1) The Company recognized probable outflow of resources amounting to ￦ ￦ (*2) Due to contamination of lands near the Company’s magnesium smelting plant located in Gangneung province and others, the Company recognized present values of estimated costs for recovery, ￦ (*3) As of December 31, 2017 and 2018, POSCO ENERGY CO., LTD., a subsidiary of the Company, recognized ￦ ￦ (*4) As of December 31, 2017 and 2018, the amount includes a provision of ￦ ￦
Changes in Provisions	Changes in provisions for the years ended December 31, 2017 and 2018 were as follows: 1) For the year ended December 31, 2017 Beginning Increase Utilization Reversal Others (*1) Ending (in millions of Won) Provision for bonus payments ￦ 42,986 74,728 (64,319 ) (3,035 ) (1,189 ) 49,171 Provision for construction warranties 96,709 40,916 (18,006 ) (2,502 ) 919 118,036 Provision for legal contingencies and claims 84,846 27,459 (70,156 ) (1,749 ) (3,636 ) 36,764 Provision for the restoration 62,594 63,438 (8,530 ) — 16,688 134,190 Others 165,469 161,054 (64,850 ) (20,199 ) 8,483 249,957 ￦ 452,604 367,595 (225,861 ) (27,485 ) 21,265 588,118 (*1) Includes adjustments of foreign currency translation differences and others. 2) For the year ended December 31, 2018 Beginning Increase Utilization Reversal Others (*1) Ending (in millions of Won) Provision for bonus payments ￦ 49,171 88,879 (60,723 ) (3,856 ) 7 73,478 Provision for construction warranties 118,036 56,560 (24,608 ) (7,660 ) (95 ) 142,233 Provision for legal contingencies and claims 36,764 45,789 (6,066 ) (3,399 ) (391 ) 72,697 Provision for the restoration 134,190 14,912 (9,212 ) (47,682 ) (3,040 ) 89,168 Others 249,957 367,332 (118,388 ) (216,668 ) 69,680 351,913 ￦ 588,118 573,472 (218,997 ) (279,265 ) 66,161 729,489 (*1) Includes adjustments of foreign currency translation differences and others.

Employee Benefits (Tables)

Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Expense Related to Post-employment Benefit Plans under Defined Contribution Plans	The expenses related to post-employment benefit plans under defined contribution plans for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Expense related to post-employment benefit plans under defined contribution plans ￦ 30,344 35,538 42,825
Amounts Recognized in Relation to Net Defined Benefit Liabilities in Statements of Financial Position	The amounts recognized in relation to net defined benefit liabilities in the statements of financial position as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Present value of funded obligations ￦ 1,826,907 2,117,829 Fair value of plan assets (*1) (1,714,166 ) (1,997,717 ) Present value of non-funded 16,228 19,332 Net defined benefit liabilities ￦ 128,969 139,444 (*1) As of December 31, 2017 and 2018, the Company recognized net defined benefit assets amounting to ￦ ￦
Changes in Present Value of Defined Benefit Obligations and Fair Value of Plan Assets	Changes in present value of defined benefit obligations for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Defined benefit obligations at the beginning of period ￦ 1,733,020 1,843,135 Current service costs 209,612 212,323 Interest costs 35,830 54,950 Remeasurements : 51,994 212,678 — Gain from change in financial assumptions (50,218 ) 173,084 — Loss (gain) from change in demographic assumptions 15,952 526 — Others 86,260 39,068 Benefits paid (185,220 ) (189,165 ) Others (2,101 ) 3,240 Defined benefit obligations at the end of period ￦ 1,843,135 2,137,161 Changes in fair value of plan assets for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Fair value of plan assets at the beginning of period ￦ 1,693,118 1,714,166 Interest on plan assets 45,516 50,784 Remeasurement of plan assets (17,190 ) (19,761 ) Contributions to plan assets 164,828 408,326 Benefits paid (168,643 ) (163,112 ) Others (3,463 ) 7,314 Fair value of plan assets at the end of period ￦ 1,714,166 1,997,717
Fair Value of Plan Assets	The fair value of plan assets as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Equity instruments ￦ 41,218 3,151 Debt instruments 367,027 692,825 Deposits 1,254,571 1,244,802 Others 51,350 56,939 ￦ 1,714,166 1,997,717
Amounts Recognized in Consolidated Statements of Comprehensive Income	The amounts recognized in consolidated statements of comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Current service costs ￦ 285,706 209,612 212,323 Net interest costs (*1) 1,901 (9,686 ) 4,166 ￦ 287,607 199,926 216,489 (*1) The actual return on plan assets amounted to ￦ ￦ ￦ The above expenses by function were as follows: 2016 2017 2018 (in millions of Won) Cost of sales ￦ 161,810 131,724 150,822 Selling and administrative expenses 124,994 67,424 64,505 Others 803 778 1,162 ￦ 287,607 199,926 216,489
Accumulated Actuarial Gains (Losses), Net of Tax Recognized in Other Comprehensive Income	Accumulated actuarial gains (losses), net of tax recognized in other comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Beginning ￦ (272,152 ) (251,612 ) (299,155 ) Current actuarial gains (losses) 20,540 (47,543 ) (173,489 ) Ending ￦ (251,612) (299,155 ) (472,644 )
Principal Actuarial Assumptions	The principal actuarial assumptions as of December 31, 2017 and 2018 are as follows: 2017 2018 (%) Discount rate 2.70~7.75 2.24~10.03 Expected future increase in salaries (*1) 1.04~10.00 2.54~10.00 (*1) The expected future increase in salaries is based on the average salary increase rate for the past 3~5 years.
Changes to Defined Benefit Obligation Due to Reasonably Possible Changes to one of the Relevant Actuarial Assumptions	Reasonably possible changes at the reporting date to one of the relevant actuarial assumptions, holding the other assumptions constant, would have affected the defined benefit obligation by the amounts shown below: 1% Increase 1% Decrease Amount Percentage (%) Amount Percentage (%) (in millions of Won) Discount rate ￦ (143,793 ) (6.7 ) 166,225 7.8 Expected future increase in salaries 167,278 7.8 (147,232 ) (6.9 )
Maturity of Expected Benefit Payments	As of December 31, 2018 the maturity of the expected benefit payments are as follows: Within 1 year - 5 years - 10 years - After Total (in millions of Won) Benefits paid ￦ 110,168 735,172 836,318 795,347 491,384 2,968,389

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Other Liabilities	Other liabilities as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Current Due to customers for contract work ￦ 782,968 641,064 Advances received 1,183,108 1,130,910 Unearned revenue 7,121 49,805 Withholdings 221,940 233,981 Firm commitment liability 12,192 24,373 Others 33,590 10,174 ￦ 2,240,919 2,090,307 Non-current Advances received 357,981 148,081 Unearned revenue 18,440 42,992 Others 10,010 59,359 ￦ 386,431 250,432

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Summary of Carrying Amount and Fair Values of Financial Assets and Financial Liabilities by Fair value	The carrying amount and the fair values of financial assets and financial liabilities by fair value hierarchy as of December 31, 2017 and 2018 are as follows: ① December 31, 2017 Fair value Book value Level 1 Level 2 Level 3 Total (in millions of Won) Financial assets Financial assets at fair value through profit or loss Financial assets held for trading ￦ 1,970 — 1,970 — 1,970 Derivatives assets held for trading 65,051 — 65,051 — 65,051 Derivative hedging instruments 3,239 — 3,239 — 3,239 Available-for-sale 1,978,115 1,080,291 17,812 880,012 1,978,115 Held-to-maturity 5,211 — — — — Loans and receivables (*1) Cash and cash equivalents 2,612,530 — — — — Trade accounts and notes receivable 8,898,176 — — — — Loans and other receivables 9,099,444 — — — — ￦ 22,663,736 1,080,291 88,072 880,012 2,048,375 Financial liabilities Financial liabilities at fair value through profit or loss Derivative liabilities held for trading ￦ 142,280 — 142,280 — 142,280 Derivative hedging instruments 13,230 — 13,230 — 13,230 Financial liabilities measured at amortized cost (*1) Trade accounts and notes payable 3,477,678 — — — — Borrowings 21,063,657 — 21,217,415 — 21,217,415 Financial guarantee liabilities 88,407 — — — — Others 1,865,683 — — — — ￦ 26,650,935 — 21,372,925 — 21,372,925 (*1) Fair value of financial assets and liabilities measured at amortized cost except borrowings approximates carrying amounts. ② December 31, 2018 Fair value Book value Level 1 Level 2 Level 3 Total (in millions of Won) Financial assets Fair value through profit or loss Derivative assets ￦ 16,662 — 16,662 — 16,662 Short-term financial instruments 6,099,303 — 6,099,303 — 6,099,303 Debt securities 27,229 — — 27,229 27,229 Other securities 338,106 1,224 5,205 331,677 338,106 Other receivables 2,000 — — 2,000 2,000 Derivative hedging instruments (*2) 32,421 — 32,421 — 32,421 Fair value through other comprehensive income Equity securities 1,238,630 891,514 — 347,116 1,238,630 Debt securities 1,638 — — 1,638 1,638 Financial assets measured at amortized cost (*1) Cash and cash equivalents 2,643,865 — — — — Trade accounts and notes receivable 8,819,617 — — — — Other receivables 1,843,381 — — — — Debt securities 8,447 — — — — Deposit instruments 1,966,558 — — — — ￦ 23,037,857 892,738 6,153,591 709,660 7,755,989 Financial liabilities Fair value through profit or loss Derivative liabilities ￦ 60,047 — 60,047 — 60,047 Derivative hedging instruments (*2) 13,710 — 13,710 — 13,710 Financial liabilities measured at amortized cost (*1) Trade accounts and notes payable 4,035,960 — — — — Borrowings 20,209,270 — 20,377,105 — 20,377,105 Financial guarantee liabilities 68,205 — — — — Others 1,803,353 — — — — ￦ 26,190,545 — 20,450,862 — 20,450,862 (*1) Fair value of financial assets and liabilities measured at amortized cost except borrowings approximates carrying amounts. (*2) The Company applies hedge accounting which uses forward contracts as hedging instrument in order to hedge the risk of changes in fair value of product prices regarding firm commitments or purchase commitments. Also, the Company applies cash flow accounting which uses currency swap as hedging instrument in order to hedge the risk of changes in foreign currency which influences cash flow from borrowings.
Value Measurement Method and Significant but not Observable Inputs for the Financial Assets Classified as Fair Value Hierarchy Level 3	① Value measurement method and significant but not observable inputs for the financial assets classified as fair value hierarchy Level 3 as of December 31, 2018 are as follows: Fair value Valuation technique Inputs Range of inputs Effect on fair value (in millions of Won) Financial assets at fair value ￦ 303,377 Discounted cash flows Growth rate 0% ~ 0.5% As growth rate increases, fair value increases Discount rate 6.4% ~ 13.8% As discount rate increases, fair value decreases 23,747 Proxy firm valuation method Price multiples 1.085 ~ 5.245 As price multiples increases, fair value increases 382,536 Asset value approach — — —
Sensitivity Analysis of Financial Assets and Financial Liabilities Classified as Level 3 of Fair Value Hierarchy	② Sensitivity analysis of financial assets and financial liabilities classified as Level 3 of fair value hierarchy If other inputs remain constant as of December 31, 2018 and one of the significant but not observable input is changed, the effect on fair value measurement is as follows: Input variable Favorable Unfavorable (in millions of Won) Financial assets at fair value Fluctuation 0.5% of growth rate ￦ 1,563 958 Fluctuation 0.5% of discount rate 17,332 15,715
Finance Income and Costs by Category of Financial Instruments	Finance income and costs by category of financial instrument for the years ended December 31, 2016, 2017 and 2018 were as follows: ① For the year ended December 31, 2016 Finance income and costs Other Interest Gain and Gain and Gain and Impairment Others Total (in millions of Won) Derivatives assets ￦ — 57,411 — 310,625 — — 368,036 — Available-for-sale 431 — — 127,524 (248,404 ) 41,000 (79,449 ) 310,608 Held-to-maturity 266 — — — — 38 304 — Loans and receivables 181,778 — 140,751 (17,854 ) — (172 ) 304,503 — Derivatives liabilities — (72,976 ) — (332,415 ) — — (405,391 ) — Financial liabilities measured at (658,726 ) — (283,059 ) (61 ) — (28,367 ) (970,213 ) — ￦ (476,251 ) (15,565 ) (142,308 ) 87,819 (248,404 ) 12,499 (782,210 ) 310,608 ② Finance income and costs Interest Gain and Gain and Gain and Impairment Others Total Other (in millions of Won) Financial assets held for trading ￦ — 16 — — — — 16 — Derivatives assets — (99,942 ) — 206,362 — — 106,420 (143 ) Available-for-sale 60 — — 418,789 (123,214 ) 92,961 388,596 (31,389 ) Held-to-maturity 236 — — — — 7 243 — Loans and receivables 212,155 — (607,837 ) (32,456 ) — (304 ) (428,442 ) — Derivatives liabilities — (61,809 ) — (231,908 ) — — (293,717 ) — Financial liabilities measured (653,115 ) — 777,935 — — (9,546 ) 115,274 — ￦ (440,664 ) (161,735 ) 170,098 360,787 (123,214 ) 83,118 (111,610 ) (31,532 ) ③ Finance income and costs Interest Gain and Gain and Gain and Others Total Other comprehensive (in millions of Won) Financial assets at fair value through profit or loss ￦ 140,116 (43,293 ) — 11,919 3,644 112,386 — Derivative assets — 47,720 — 233,187 — 280,907 — Financial assets at fair value through other comprehensive income — — — — 59,701 59,701 (149,188 ) Financial assets measured at amortized cost 197,142 — 234,606 (39,970 ) (370 ) 391,408 — Derivative liabilities — 8,592 — (194,446 ) — (185,854 ) (212 ) Financial liabilities measured at amortized cost (741,296 ) — (438,708 ) — (16,990 ) (1,196,994 ) — ￦ (404,038 ) 13,019 (204,102 ) 10,690 45,985 (538,446 ) (149,400 )
Maximum Exposure to Credit Risk	The carrying amount of financial assets represents the Company’s maximum exposure to credit risk. The maximum exposure to credit risk as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Cash and cash equivalents ￦ 2,612,530 2,643,865 Derivative assets 68,290 49,083 Short-term financial instrument 5,545,667 6,099,303 Debt securities — 37,314 Other securities — 338,106 Financial assets held for trading 1,970 — Available-for-sale 192,866 — Held-to-maturity 5,211 — Other receivables 2,195,466 1,845,381 Trade accounts and notes receivable 8,898,176 8,819,617 Deposit instruments 1,358,311 1,966,558 ￦ 20,878,487 21,799,227
Allowance for Doubtful Accounts	① 2017 2018 (in millions of Won) Trade accounts and notes receivable ￦ 634,129 588,733 Other accounts receivable 187,706 160,729 Loans 258,957 147,980 Other assets 13,672 19,348 ￦ 1,094,464 916,790
Impairment Losses on Financial Assets	② 2017 2018 (in millions of Won) Bad debt expenses ￦ 173,694 74,781 Other bad debt expenses (*1) 100,920 81,353 Impairment loss on available-for-sale 123,214 — Less: Recovery of allowance for other bad debt accounts (2,743 ) (18,261 ) Less: Recovery of impairment loss on held-to-maturity (20 ) — ￦ 395,065 137,873 (*1) Other bad debt expenses are mainly related to loans and other accounts receivable.
Aging and Impairment Losses of Trade Accounts and Notes Receivable and Other Receivables	③ 2017 2018 Trade accounts Allowance for Trade accounts Allowance for (in millions of Won) Not due ￦ 7,736,092 65,314 8,021,110 70,418 Overdue less than 1 month 445,390 12,546 632,082 14,434 1 month – 3 months 170,682 742 226,082 4,116 3 months – 12 months 384,313 21,030 118,094 11,774 Over 12 months 1,453,785 534,497 1,148,694 487,991 ￦ 10,190,262 634,129 10,146,062 588,733 ④ 2017 2018 Loans and Allowance for Loans and Allowance for (in millions of Won) Not due ￦ 1,888,726 9,672 1,754,293 140,072 Overdue less than 1 month 235,559 35,539 100,102 4,307 1 month – 3 months 69,372 54,335 28,351 851 3 months – 12 months 96,942 64,467 59,946 12,411 Over 12 months 365,202 296,322 230,746 170,416 ￦ 2,655,801 460,335 2,173,438 328,057
Changes in Allowance for Doubtful Accounts	⑤ 2016 2017 2018 (in millions of Won) Beginning ￦ 999,678 977,771 1,094,464 Initial application of IFRS No.9 — — 107,454 Bad debt expenses 165,150 173,694 74,781 Other bad debt expenses 37,567 98,177 63,092 Others (*1) (224,624 ) (155,178 ) (423,001 ) Ending ￦ 977,771 1,094,464 916,790 (*1) Others for the year ended December 31, 2016, 2017 and 2018, included decreases mainly due to write-off ￦ ￦ ￦
Contractual Maturities for Non-derivative Financial Liabilities	1) Contractual maturities for non-derivative Book value Contractual Within 1 year - After (in millions of Won) Trade accounts and notes payable ￦ 4,035,960 4,037,863 4,006,942 30,921 — Borrowings 20,209,270 24,319,619 12,912,399 10,452,389 954,831 Financial guarantee liabilities (*1) 68,205 3,147,280 3,147,280 — — Other financial liabilities 1,803,353 1,817,014 1,668,937 148,077 — ￦ 26,116,788 33,321,776 21,735,558 10,631,387 954,831 (*1) For issued financial guarantee contracts, the maximum amount of the guarantee is allocated to the earliest period in which the guarantee could be called.
Contractual Maturities Analysis of Derivative Financial Liabilities	2) Contractual maturities for derivative financial liabilities are as follows: Within 1 year 1 year - After Total (in millions of Won) Currency forward ￦ 11,364 34,743 — 46,107 Currency swap 1,707 5,849 4,369 11,925 Interest swap — 1,467 — 1,467 Others 14,258 — — 14,258 ￦ 27,329 42,059 4,369 73,757
Currency risk [member]
Statement [LineItems]
Market Risk Exposure	1) The Company has exposure to the risk that the fair value or future cash flows of a financial instrument will fluctuate because of the changes in foreign exchange rates. The exposure to currency risk as of December 31, 2017 and 2018 are as follows: 2017 2018 Assets Liabilities Assets Liabilities (in millions of Won) USD ￦ 4,215,151 5,940,380 4,346,481 6,389,276 EUR 552,630 454,072 657,690 509,437 JPY 165,356 709,318 97,722 389,625 Others 220,723 117,632 259,949 142,868
Sensitivity Analysis for Market Risk	2) As of December 31, 2017 and 2018, provided that functional currency against foreign currencies other than functional currency hypothetically strengthens or weakens by 10%, the changes in gain or loss for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 10% increase 10% decrease 10% increase 10% decrease (in millions of Won) USD ￦ (172,523 ) 172,523 (204,280 ) 204,280 EUR 9,856 (9,856 ) 14,825 (14,825 ) JPY (54,396 ) 54,396 (29,190 ) 29,190
Interest rate risk [member]
Statement [LineItems]
Market Risk Exposure	1) The carrying amount of interest-bearing financial instruments as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Fixed rate Financial assets ￦ 10,943,300 11,565,519 Financial liabilities (11,179,635 ) (11,781,701 ) (236,335 ) (216,182 ) Variable rate Financial liabilities ￦ (9,977,040) (8,522,323 )
Sensitivity Analysis for Market Risk	As of December 31, 2017 and 2018, provided that other factors remain the same and the interest rate of borrowings with floating rates increases or decreases by 1%, the changes in interest expense for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 1% increase 1% decrease 1% increase 1% decrease (in millions of Won) Variable rate financial instruments ￦ (99,770) 99,770 (85,223 ) 85,223
Level 3 [member]
Statement [LineItems]
Fair Values of Financial Assets and Financial Liabilities	③ Changes in fair value of financial assets and financial liabilities classified as Level 3 for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 (in millions of Won) Beginning ￦ 349,090 880,012 Acquisition and others 658,359 134,325 Gain (loss) on valuations of derivatives (10,346 ) (34,555 ) Other comprehensive income (loss) 35,126 26,771 Impairment (107,934 ) — Disposal and others (44,283 ) (296,893 ) Ending ￦ 880,012 709,660

Share Capital and Capital Sur_2

Share Capital and Capital Surplus (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Share Capital	(a) Share capital as of December 31, 2017 and 2018 are as follows: 2017 2018 (Share, in Won) Authorized shares 200,000,000 200,000,000 Par value ￦ 5,000 5,000 Issued shares (*1) 87,186,835 87,186,835 Shared capital (*2) ￦ 482,403,125,000 482,403,125,000 (*1) As of December 31, 2018, total shares of ADRs of 36,860,288 outstanding in overseas stock market are equivalent to 9,215,072 of common stock. (*2) As of December 31, 2018, the difference between the ending balance of common stock and the par value of issued common stock is ￦
Changes in Issued Common Stock	(b) The changes in issued common stock for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Issued Treasury Number of Issued Treasury Number of (share) Beginning 87,186,835 (7,189,170 ) 79,997,665 87,186,835 (7,187,231 ) 79,999,604 Disposal of treasury shares — 1,939 1,939 — 1,528 1,528 Ending 87,186,835 (7,187,231 ) 79,999,604 87,186,835 (7,185,703 ) 80,001,132
Summary of Capital Surplus	(c) Capital surplus as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Share premium ￦ 463,825 463,825 Gain on disposal of treasury shares 783,914 784,047 Other capital deficit 174,282 172,135 ￦ 1,422,021 1,420,007
Summary of Redeemable Convertible Preferred Shares	(d) POSCO Energy Co., Ltd., a subsidiary of the Company, issued redeemable convertible preferred shares which are classified as non-controlling Redeemable Convertible Preferred Shares (Share, in Won) Issue date February 25, 2017 Number of shares issued 8,643,193 shares Price per share ￦ Voting rights No voting rights for 3 years from issue date Dividend rights Comparative, Non-participating Details about Redemption Issuer can demand redemption of all or part of redeemable convertible preferred shares every year after the issue date, for a period of 10 years from the issue date. Details about Conversion Stockholders of redeemable convertible preferred shares can convert them to common shares from 3 years after the issue date to the end of the redemption period (10 years).

Hybrid Bonds (Tables)

Hybrid Bonds (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Summary of Hybrid Bonds	(a) Hybrid bonds classified as equity as of December 31, 2017 and 2018 are as follows: Date of Date of maturity Interest rate (%) 2017 2018 (in millions of Won) Hybrid bond 1-1 (*1) — — — ￦ 800,000 — Hybrid bond 1-2 (*2) 2013-06-13 2043-06-13 4.60 200,000 200,000 Issuance cost (3,081 ) (616 ) ￦ 996,919 199,384 (*1) During the year ended December 31, 2018, the Company exercised the call option of the Hybrid bond. (*2) Details of issuance of hybrid bonds as of December 31, 2018 are as follows: Hybrid bond 1-2 Maturity date 30 years (POSCO has a right to extend the maturity date) Interest rate Issue date ~ 2023-06-12 Step-up Interest payments condition Quarterly (Optional deferral of interest payment is available to POSCO) Others POSCO can call the hybrid bond at year 10 and interest payment date afterwards
POSCO ENERGY CO., LTD. [member]
Statement [LineItems]
Summary of Hybrid Bonds	(b) POSCO ENERGY CO., LTD., a subsidiary of the Company, issued hybrid bonds, which are classified as non-controlling Date of issue Date of maturity Interest rate (%) 2017 2018 (in millions of Won) Hybrid bond 1-1 (*1) — — — ￦ 165,000 — Hybrid bond 1-2 (*1) — — — 165,000 — Hybrid bond 1-3 (*1) — — — 30,000 — Hybrid bond 1-4 (*2) 2013-08-29 2043-08-29 5.21 140,000 140,000 Issuance cost (1,532 ) (429 ) ￦ 498,468 139,571 (*1) During the year ended December 31, 2018, the Company exercised the call option for the Hybrid bond. (*2) Details of issuance of hybrid bonds of POSCO ENERGY Co., Ltd .as of December 31, 2018 are as follows: Hybrid bond 1-4 Maturity date 30 years (The Company has a right to extend the maturity date) Interest rate Issue date ~ 2023-08-29 Step-up Interest payments condition Quarterly (Optional deferral of interest payment is available to the issuer) Others The issuer can call the hybrid bond at year 10 and interest payment date afterwards

Reserves (Tables)

Reserves (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Summary of Reserves	(a) Reserves as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Accumulated comprehensive loss of investments in associates and joint ventures ￦ (516,528 ) (670,435 ) Changes in fair value of equity investments at fair value through other comprehensive income — (295,300 ) Changes in the unrealized fair value of available-for-sale 230,190 — Foreign currency translation differences (372,166 ) (417,817 ) Gain or losses on valuation of derivatives (136 ) (352 ) Others (23,916 ) (20,464 ) ￦ (682,556 ) (1,404,368 )
Unrealized fair value of available-for-sale investments [member]
Statement [LineItems]
Summary of Reserves	(b) Changes in unrealized fair value of available-for-sale 2017 2018 (in millions of Won) Beginning balance ￦ 276,143 230,190 Initial application of IFRS No. 9 — (421,525 ) Changes in unrealized fair value of equity investments 183,761 (139,226 ) Reclassification upon disposal (299,862 ) 45,737 Impairment of available-for-sale 96,083 — Others (25,935 ) (10,476 ) Ending balance ￦ 230,190 (295,300 )

Treasury Shares (Tables)

Treasury Shares (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Changes in Treasury Shares	The changes in treasury shares for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Number of shares Amount Number of shares Amount (shares, in millions of Won) Beginning 7,189,170 ￦ 1,533,468 7,187,231 ￦ 1,533,054 Disposal of treasury shares (1,939 ) (414 ) (1,528 ) (326 ) Ending 7,187,231 ￦ 1,533,054 7,185,703 ￦ 1,532,728

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Revenue Disaggregated by Types of Revenue and Timing of Revenue Recognition	1) Details of revenue disaggregated by types of revenue and timing of revenue recognition for the years ended December 31, 2016, 2017 and 2018 were as follows: ① For the year ended December 31, 2016 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 26,687,899 16,602,482 11,496 243,149 43,545,026 Revenue from services 102,657 24,703 50,189 2,237,129 2,414,678 Revenue from construction contract — — 6,474,192 23,087 6,497,279 Others 53,599 146,893 88,728 193,568 482,788 ￦ 26,844,155 16,774,078 6,624,605 2,696,933 52,939,771 Timing of revenue recognition Revenue recognized at a point in time ￦ 26,741,498 16,749,375 100,224 446,667 44,037,764 Revenue recognized over time 102,657 24,703 6,524,381 2,250,266 8,902,007 ￦ 26,844,155 16,774,078 6,624,605 2,696,933 52,939,771 ② For the year ended December 31, 2017 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 30,064,680 20,655,267 20,368 617,394 51,357,709 Revenue from services 111,494 28,793 48,408 1,876,179 2,064,874 Revenue from construction contract — — 6,262,038 37,154 6,299,192 Others 54,194 118,147 87,559 205,192 465,092 ￦ 30,230,368 20,802,207 6,418,373 2,735,919 60,186,867 Timing of revenue recognition Revenue recognized at a point in time ￦ 30,118,874 20,773,414 107,927 832,369 51,832,584 Revenue recognized over time 111,494 28,793 6,310,446 1,903,550 8,354,283 ￦ 30,230,368 20,802,207 6,418,373 2,735,919 60,186,867 ③ For the year ended December 31, 2018 Steel Trading Construction Others Total (in millions of Won) Types of revenue Revenue from sales of goods ￦ 31,733,609 21,632,183 3,568 605,206 53,974,566 Revenue from services 583,359 611,752 63,922 2,274,606 3,533,639 Revenue from construction contract — — 6,860,995 272,778 7,133,773 Others 41,041 163,782 17,784 290,051 512,658 ￦ 32,358,009 22,407,717 6,946,269 3,442,641 65,154,636 Timing of revenue recognition Revenue recognized at a point in time ￦ 31,774,650 21,795,965 127,182 906,120 54,603,917 Revenue recognized over time 583,359 611,752 6,819,087 2,536,521 10,550,719 ￦ 32,358,009 22,407,717 6,946,269 3,442,641 65,154,636
Summary of Contract Assets and Liabilities From Contracts With Customers	(b) Details of contract assets and liabilities from contracts with customers as of December 31, 2018 and January 1, 2018, the initial application date of IFRS No. 15 “Revenue from Contracts with Customers” and IFRS No. 9 “Financial Instruments”, are as follows; The date of initial 2018 (in millions of Won) Receivables Account receivables ￦ 8,795,470 8,819,617 Contract assets Due from customers for contract work 647,385 737,712 Contract liabilities Advance received 1,547,247 1,278,731 Due to customers for contract work 751,933 641,064 Unearned revenue 77,657 91,872

Revenue - Contract Balances (Ta

Revenue - Contract Balances (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of In-Progress Contracts	(a) Details of in-progress 2017 2018 (in millions of Won) Accumulated cost ￦ 21,404,321 26,153,452 Accumulated contract profit 1,524,208 1,848,718 Accumulated contract loss (718,593 ) (804,538 ) Accumulated contract revenue 22,209,936 27,197,632
Summary of Due From Customers for Contract Work and Due to Customers for Contract Work	(b) Details of due from customers for contract work and due to customers for contract work as of December 31, 2017 and 2018 are as follows: 2017 2018 (in millions of Won) Unbilled due from customers for contract work ￦ 728,007 810,655 Due to customers for contract work (782,968 ) (641,064 ) ￦ (54,961 ) 169,591
Summary of Changes in Estimated Total Contract Costs and Impact on Profit or Loss	Due to the factors causing the variation of costs for the years ended December 31, 2017 and 2018, the estimated total contract costs have changed. Details of changes in estimated total contract costs and the impact on profit before income taxes for the years ended December 31, 2017, 2018 and future periods are as follows: 2017 2018 (in millions of Won) Changes in estimated total contract costs ￦ 164,812 427,812 Changes in profit before income taxes of construction contract : - Current period (69,656 ) (38,720 ) - Future periods (6,041 ) 69,428
Summary of Significant Assumptions Including Uncertainty of Estimate of Total Contract Costs	The significant assumptions including uncertainty of the estimate of total contract costs are as follows: Method of significant assumption Material cost Assumption based on recent purchasing price and quoted market price Labor cost Assumption based on standard monthly and daily labor cost Outsourcing cost Assumption based on the past experience rate of similar project and market price

Selling and Administrative Ex_2

Selling and Administrative Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Other Administrative Expenses	Other administrative expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Wages and salaries ￦ 769,589 774,900 813,467 Expenses related to post-employment benefits 200,956 78,654 73,290 Other employee benefits 176,794 159,920 176,240 Travel 40,828 39,790 40,929 Depreciation 103,442 97,261 101,274 Amortization 139,569 146,314 112,418 Communication 11,186 11,740 10,616 Electricity expenses 7,527 7,050 8,309 Taxes and public dues 78,895 72,826 71,973 Rental 82,005 69,976 69,516 Repairs 11,316 9,859 15,291 Entertainment 13,157 11,582 11,816 Advertising 86,141 119,724 106,875 Research & development 120,608 125,795 108,352 Service fees 201,129 193,387 165,938 Vehicles maintenance 10,090 8,211 8,942 Industry association fee 13,468 10,140 9,571 Conference 13,108 14,494 14,510 Increase to provisions 6,532 10,990 14,433 Others 40,050 40,493 51,995 ￦ 2,126,390 2,003,106 1,985,755
Summary of Selling Expenses	Selling expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Freight and custody expenses (*1) ￦ 1,342,009 1,336,969 184,675 Operating expenses for distribution center 10,315 10,503 10,614 Sales commissions 94,377 115,925 79,080 Sales advertising 5,117 3,800 4,821 Sales promotion 10,670 12,414 13,792 Sample 2,335 1,989 2,716 Sales insurance premium 31,379 36,546 37,251 Contract cost 49,480 23,061 16,992 Others 8,004 16,070 19,304 ￦ 1,553,686 1,557,277 369,245 (*1) During the year ended December 31, 2018, the Company recognized the freight expenses included in selling expenses incurred for the delivery of transportation services identified as a separate performance obligations in cost of sales.

Research and Development Expe_2

Research and Development Expenditures Recognized as Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Research and Development Expenditures Recognized as Expenses	Research and development expenditures recognized as expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Administrative expenses ￦ 120,608 125,795 108,352 Cost of sales 324,190 361,093 418,250 ￦ 444,798 486,888 526,602

Other Operating Income and Ex_2

Other Operating Income and Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Details of Other Operating Income and Expenses	Details of other operating income and expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Other operating income Gain on disposals of assets held for sale ￦ 23,112 1,180 27,171 Gain on disposals of investment in subsidiaries, associates and joint ventures 23,305 81,794 45,241 Gain on disposals of property, plant and equipment 23,826 32,145 53,139 Gain on disposals of intangible assets 671 23,391 117,139 Gain on valuation of firm commitment — 56,301 39,028 Gain on insurance proceeds 22,400 5,878 14,034 Others (*1,2) 109,164 247,792 227,834 ￦ 202,478 448,481 523,586 Other operating expenses Impairment loss on assets held for sale ￦ (24,890 ) — (50,829 ) Loss on disposals of investments in subsidiaries, associates and joint ventures (22,499 ) (19,985 ) (5,226 ) Loss on disposals of property, plant and equipment (86,622 ) (151,343 ) (117,614 ) Impairment loss on property, plant and equipment (196,882 ) (117,231 ) (1,004,704 ) Impairment loss on investment property (318 ) — (51,461 ) Loss on disposals of investment property (21 ) (1,966 ) (9,154 ) Impairment loss on intangible assets (127,875 ) (167,995 ) (337,519 ) Increase to provisions (53,058 ) (33,964 ) (134,632 ) Loss on valuation of firm commitment — (43,164 ) (66,281 ) Donations (43,810 ) (51,424 ) (52,074 ) Idle tangible asset expenses (6,437 ) (10,490 ) (9,257 ) Others (*3) (143,083 ) (93,814 ) (175,711 ) ￦ (705,495 ) (691,376 ) (2,014,462 ) (*1) During the year ended December 31, 2018, the Controlling Company recognized ￦ (*2) The Company has recognized the refund of VAT and others amounting to ￦ (*3) During the year ended December 31, 2018, the Controlling Company recognized ￦

Finance Income and Costs (Table

Finance Income and Costs (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Details of Finance Income and Costs	Details of finance income and costs for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Finance income Interest income (*1) ￦ 182,475 212,451 337,258 Dividend income 41,000 92,962 63,345 Gain on foreign currency transactions 1,032,552 785,616 716,060 Gain on foreign currency translations 377,723 564,016 212,443 Gain on derivatives transactions 316,524 210,727 247,513 Gain on valuations of derivatives 147,111 64,735 96,986 Gain on disposals of available-for-sale 130,830 425,684 — Gain on valuations of financial assets at fair value through profit or loss — — 16,149 Others 3,765 16,476 16,216 ￦ 2,231,980 2,372,667 1,705,970 Finance costs Interest expenses ￦ (658,726 ) (653,115 ) (741,296 ) Loss on foreign currency transactions (1,147,192 ) (756,654 ) (810,857 ) Loss on foreign currency translations (405,391 ) (422,880 ) (321,748 ) Loss on derivatives transactions (338,314 ) (236,273 ) (208,772 ) Loss on valuation of derivatives (162,676 ) (226,487 ) (40,674 ) Impairment loss on available-for-sale (248,404 ) (123,214 ) — Loss on valuations of financial assets at fair value through profit or loss — — (59,442 ) Others (53,487 ) (65,654 ) (61,627 ) ￦ (3,014,190 ) (2,484,277 ) (2,244,416 ) (*1) Interest income calculated using the effective interest method for the years ended December 31, 2016, 2017, and 2018 were ￦ ￦ ￦

Expenses by Nature (Tables)

Expenses by Nature (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Expenses by Nature	Expenses that are recorded by nature as cost of sales, selling and administrative expenses, impairment loss on other receivables and other operating expenses in the statements of comprehensive income for the years ended December 31, 2016, 2017 and 2018 were as follows (excluding finance costs and income tax expense): 2016 2017 2018 (in millions of Won) Raw material used, changes in inventories and others ￦ 30,177,732 35,584,184 38,884,690 Employee benefits expenses (*2) 3,444,276 3,357,861 3,639,192 Outsourced processing cost 7,678,055 7,074,948 7,462,656 Electricity expenses 1,018,429 933,045 949,435 Depreciation (*1) 2,835,843 2,887,646 2,911,048 Amortization 378,004 409,774 356,581 Freight and custody expenses 1,342,009 1,336,969 1,414,940 Sales commissions 94,377 115,925 79,080 Loss on disposal of property, plant and equipment 86,622 151,343 117,614 Impairment loss on property, plant and equipment 196,882 117,231 1,004,704 Impairment loss on goodwill and intangible assets 127,875 167,995 337,519 Donations 43,810 51,424 52,074 Other expenses 3,448,497 4,253,625 4,445,124 ￦ 50,872,411 56,441,970 61,654,657 (*1) Includes depreciation expense of investment property. (*2) The details of employee benefits expenses for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Wages and salaries ￦ 3,016,488 3,105,364 3,372,831 Expenses related to post-employment benefits 427,788 252,497 266,361 ￦ 3,444,276 3,357,861 3,639,192

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Summary of Income Tax Expense	(a) Income tax expense for the years ended December 31, 2016, 2017 and 2018 was as follows: 2016 2017 2018 (in millions of Won) Current income taxes (*1) ￦ 699,269 864,143 1,577,581 Deferred income tax due to temporary differences (209,706 ) 300,037 (38,851 ) Items recorded directly in equity (110,019 ) 21,560 144,900 Income tax expense ￦ 379,544 1,185,740 1,683,630 (*1) Refund (additional payment) of income taxes when filing a final corporation tax return credited (charged) directly to current income taxes.
Income Tax Credit (Charged) Directly to Equity	(b) The income taxes credited (charged) directly to equity for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in millions of Won) Net changes in fair value of equity investments at fair value through other comprehensive income ￦ (100,550 ) 1,271 47,423 Remeasurements of defined benefit plans (11,722 ) 22,208 56,289 Gain on sale of treasury shares (10 ) (40 ) (50 ) Others 2,263 (1,879 ) 41,238 ￦ (110,019 ) 21,560 144,900
Reconciliation Of Calculated Income Tax Expense Based on the Statutory Rate to Actual Amount of Taxes Recorded	(c) The following table reconciles the calculated income tax expense based on POSCO’s statutory rate (27.5%) to the actual amount of taxes recorded by the Company for the years ended December 31, 2016, 2017 and 2018. 2016 2017 2018 (in millions of Won) Profit before income tax expense ￦ 1,411,609 4,095,051 3,616,016 Income tax expense computed at statutory rate 341,148 990,540 982,287 Adjustments: Tax credits (30,124 ) (40,757 ) (32,103 ) Additional Income tax expense for prior years (11,829 ) (20,912 ) 44,336 Tax effect from tax audit — — 130,196 Investment in subsidiaries, associates and joint ventures 76,751 55,113 114,856 Tax effects due to permanent differences (9,962 ) 4,798 64,708 Effect of tax rate change (*1) — 175,647 — Others (*2) 13,560 21,311 379,350 38,396 195,200 701,343 Income tax expense ￦ 379,544 1,185,740 1,683,630 Effective tax rate (%) 26.89 % 28.96 % 46.56 % (*1) During the year ended December 31, 2017, the statutory rate changed from 24.2% to 27.5% for taxable income in excess of ￦ (*2) Includes the effect of undeductible impairment loss related to Synthetic Natural Gas (SNG) facility for the year ended December 31, 2018.
Movements in Deferred Tax Assets (Liabilities)	(d) The movements in deferred tax assets (liabilities) for the years ended December 31, 2017 and 2018 were as follows: 2017 2018 Beginning Inc. (Dec.) Ending Beginning Inc. (Dec.) Ending (in millions of Won) Deferred income tax due to temporary differences Allowance for doubtful accounts (*1) ￦ 213,119 60,875 273,994 273,994 (92,851 ) 181,143 Reserve for technology developments (91,960 ) 53,973 (37,987 ) (37,987 ) 37,987 — PP&E — Depreciation (11,639 ) 26,280 14,641 14,641 (4,804 ) 9,837 Share of profit or loss of equity-accounted investees 70,259 125,783 196,042 196,042 31,552 227,594 Allowance for inventories valuation 15,651 (4,871 ) 10,780 10,780 (104 ) 10,676 PP&E — Revaluation (1,524,149 ) (304,015 ) (1,828,164 ) (1,828,164 ) (33,548 ) (1,861,712 ) Prepaid expenses 19,665 335 20,000 20,000 (2,741 ) 17,259 PP&E — Impairment loss 5,295 245 5,540 5,540 (927 ) 4,613 Gain or loss on foreign currency translation (5,957 ) (42,515 ) (48,472 ) (48,472 ) 10,462 (38,010 ) Defined benefit obligations 361,838 68,279 430,117 430,117 70,334 500,451 Plan assets (355,661 ) (41,960 ) (397,621 ) (397,621 ) (66,940 ) (464,561 ) Provision for construction losses 997 (556 ) 441 441 6,964 7,405 Provision for construction warranty 24,322 4,395 28,717 28,717 41,601 70,318 Accrued income (9,441 ) (3,474 ) (12,915 ) (12,915 ) (179 ) (13,094 ) Others (*1) 750,151 (55,834 ) 694,317 694,317 (233,026 ) 461,291 (537,510 ) (113,060 ) (650,570 ) (650,570 ) (236,220 ) (886,790 ) Deferred income taxes recognized directly to equity Net changes in fair value of equity investments at fair value through other comprehensive income (*1) (50,507 ) 1,271 (49,236 ) (49,236 ) 206,121 156,885 Others 51,832 20,329 72,161 72,161 58,111 130,272 1,325 21,600 22,925 22,925 264,232 287,157 Deferred tax from tax credit Tax credit carry-forward and others 307,335 (189,303 ) 118,032 118,032 (2,443 ) 115,589 Investments in subsidiaries, associates and joint ventures Investments in subsidiaries, associates and joint ventures 86,130 (17,704 ) 68,426 68,426 135,512 203,938 ￦ (142,720 ) (298,467 ) (441,187 ) (441,187 ) 161,081 (280,106 ) (*1) These changes includes the cumulative impact of initial application of IFRS No. 15 and IFRS No. 9.
Summary of Deferred Tax Assets And Liabilities	(e) Deferred tax assets and liabilities for the years ended December 31, 2017 and 2018 are as follows: 2017 2018 Assets Liabilities Net Assets Liabilities Net (in millions of Won) Deferred income tax due to temporary differences Allowance for doubtful accounts ￦ 273,994 — 273,994 181,143 — 181,143 Reserve for technology developments — (37,987 ) (37,987 ) — — — PP&E — Depreciation 59,912 (45,271 ) 14,641 55,354 (45,517 ) 9,837 Share of profit or loss of equity-accounted investees 236,637 (40,595 ) 196,042 278,466 (50,872 ) 227,594 Allowance for inventories valuation 10,780 — 10,780 10,676 — 10,676 PP&E — Revaluation — (1,828,164 ) (1,828,164 ) — (1,861,712 ) (1,861,712 ) Prepaid expenses 20,000 — 20,000 17,259 — 17,259 PP&E — Impairment loss 5,639 (99 ) 5,540 5,240 (627 ) 4,613 Gain or loss on foreign currency translation 113,760 (162,232 ) (48,472 ) 121,797 (159,807 ) (38,010 ) Defined benefit obligations 430,117 — 430,117 500,451 — 500,451 Plan assets — (397,621 ) (397,621 ) — (464,561 ) (464,561 ) Provision for construction losses 441 — 441 7,405 — 7,405 Provision for construction warranty 28,717 — 28,717 70,318 — 70,318 Accrued income — (12,915 ) (12,915 ) — (13,094 ) (13,094 ) Others 746,367 (52,050 ) 694,317 857,583 (396,292 ) 461,291 1,926,364 (2,576,934 ) (650,570 ) 2,105,692 (2,992,482 ) (886,790 ) Deferred income taxes recognized directly to equity Net changes in fair value of equity investments at fair value through other comprehensive income 110,865 (160,101 ) (49,236 ) 247,921 (91,036 ) 156,885 Others 92,981 (20,820 ) 72,161 153,609 (23,337 ) 130,272 203,846 (180,921 ) 22,925 401,530 (114,373 ) 287,157 Deferred tax from tax credit Tax credit carry-forward and others 118,032 — 118,032 115,589 — 115,589 Investments in subsidiaries, associates and joint ventures Investments in subsidiaries, associates and joint ventures 563,406 (494,980 ) 68,426 547,662 (343,724 ) 203,938 ￦ 2,811,648 (3,252,835 ) (441,187 ) 3,170,473 (3,450,579 ) (280,106 )

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Basic And Diluted Earnings Per Share	Basic and diluted earnings per share for the years ended December 31, 2016, 2017 and 2018 were as follows: 2016 2017 2018 (in Won, except per share information) Profit attribute to controlling interest ￦ 1,354,806,734,940 2,756,230,487,872 1,711,901,875,666 Interests of hybrid bonds (33,225,163,081 ) (33,048,799,997 ) (17,720,986,299 ) Weighted-average number of common shares outstanding (*1) 79,996,389 79,998,600 80,000,606 Basic and diluted earnings per share ￦ 16,521 34,040 21,177 (*1) The weighted-average number of common shares used to calculate basic and diluted earnings per share are as follows: 2016 2017 2018 (shares) Total number of common shares issued 87,186,835 87,186,835 87,186,835 Weighted-average number of treasury shares (7,190,446 ) (7,188,235 ) (7,186,229 ) Weighted-average number of common shares outstanding 79,996,389 79,998,600 80,000,606

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Statement [LineItems]
Significant Financial Transactions Between the Company, Excluding the Controlling Company, and Related Parties	(e) Significant financial transactions between the Company, excluding the controlling company, and related companies for the years ended December 31, 2017 and 2018 were as follows: 1) December 31, 2017 Beginning Lend Collect Others (*4) Ending (in millions of Won) Associates and joint ventures METAPOLIS Co., Ltd. (*1) ￦ 13,270 — — (13,270 ) — New Songdo International City Development, LLC — 484,644 (201,869 ) — 282,775 GALE International Korea, LLC — 2,000 — — 2,000 DMSA/AMSA (*2) 90,638 2,956 — (23,881 ) 69,713 South-East Asia Gas Pipeline Company Ltd. 276,605 28,967 (46,252 ) (29,440 ) 229,880 PT. Batutua Tembaga Raya 38,120 — — (9,072 ) 29,048 PT. Tanggamus Electric Power 3,606 — — (409 ) 3,197 PT. Wampu Electric Power 5,761 — — (654 ) 5,107 PT. POSMI Steel Indonesia 4,834 — — (548 ) 4,286 Nickel Mining Company SAS 60,425 — — (757 ) 59,668 AN KHANH NEW CITY DEVELOPMENT J.V CO., LTD. (*1) 60,425 — — (60,425 ) — Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 6,647 — (577 ) (713 ) 5,357 KRAKATAU POS-CHEM DONG-SUH 7,251 — — (823 ) 6,428 Hamparan Mulya 3,626 — (3,626 ) — — POS-SEAH 5,438 — (5,438 ) — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 8,460 — (2,262 ) (841 ) 5,357 POS-SeAH 7,251 — (1,142 ) 319 6,428 AMCI (WA) PTY LTD 91,775 4,327 — (4,041 ) 92,061 POS-AUSTEM (*3) — — — 5,357 5,357 POS-AUSTEM (*3) — — — 8,571 8,571 SAMHWAN VINA CO., LTD (*3) — — — 1,071 1,071 ￦ 684,132 522,894 (261,166 ) (129,556 ) 816,304 (*1) During the year ended December 31, 2017, it was excluded from associates. (*2) During the year ended December 31, 2017, loans amounting to ￦ (*3) During the year ended December 31, 2017, it was newly classified to associates and joint ventures. (*4) Includes adjustments of foreign currency translation differences and others. 2) December 31, 2018 Beginning Lend Collect Others (*2) Ending (in millions of Won) Associates and joint ventures New Songdo International City Development, LLC ￦ 282,775 150 (252,759 ) (30,166 ) — GALE International Korea, LLC 2,000 8,500 (10,500 ) — — UITrans LRT Co., Ltd. — 5,695 — — 5,695 DMSA/AMSA (*1) 69,713 9,965 (342 ) (15,039 ) 64,297 South-East Asia Gas Pipeline Company Ltd. 229,880 — (47,569 ) 8,796 191,107 PT. Batutua Tembaga Raya 29,048 4,678 — 1,374 35,100 PT. Tanggamus Electric Power 3,197 — — 1,226 4,423 PT. Wampu Electric Power 5,107 — — 223 5,330 PT. POSMI Steel Indonesia 4,286 — (2,200 ) 150 2,236 Nickel Mining Company SAS 59,668 — — (4 ) 59,664 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 5,357 — (5,357 ) — — KRAKATAU POS-CHEM DONG-SUH 6,428 — — 281 6,709 POSCO SeAH Steel Wire (Nantong) Co., Ltd. 5,357 4,451 (6,454 ) — 3,354 POS-SeAH 6,428 — — 281 6,709 AMCI (WA) PTY LTD 92,061 3,795 — (5,376 ) 90,480 POS-AUSTEM 5,357 5,564 (5,357 ) 26 5,590 POS-AUSTEM 8,571 8,902 (8,571 ) 43 8,945 SAMHWAN VINA CO., LTD 1,071 — (1,071 ) — — ￦ 816,304 51,700 (340,180 ) (38,185 ) 489,639 (*1) During the year ended December 31, 2018, loans amounting to ￦ (*2) Includes adjustments of foreign currency translation differences and others.
Details of Compensation to Key Management Officers	(f) For the years ended December 31, 2016, 2017 and 2018, details of compensation to key management officers were as follows: 2016 2017 2018 (in millions of Won) Short-term benefits ￦ 90,916 112,688 115,618 Long-term benefits 17,905 8,632 13,400 Retirement benefits 17,870 20,422 21,658 ￦ 126,691 141,742 150,676
Posco [member]
Statement [LineItems]
Significant Transactions With Related Parties	(a) Significant transactions between the controlling company and related companies for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) For the year ended December 31, 2016 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 29,511 16,661 8 183,768 — 24,511 POSCO Processing & Service 1,212,220 5,778 549,803 2,896 22,704 2,445 POSCO COATED & COLOR STEEL Co., Ltd. 326,078 2,560 — — 12,232 126 POSCO ICT (*3) 1,224 727 — 219,301 32,456 171,107 eNtoB Corporation — 5 278,016 9,836 212 19,436 POSCO CHEMTECH 319,164 33,784 502,448 14,847 290,427 5,139 POSCO ENERGY CO., LTD. 187,311 1,382 — — — 7 POSCO TMC Co., Ltd. (*4) 219,489 — 2 — 863 1,177 POSCO AST (*4) 152,098 1 — — 19,695 922 POSCO DAEWOO Corporation 3,227,716 34,341 92,203 — 343 — POSCO Thainox Public Company Limited 237,471 2,915 9,593 — 19 548 POSCO America Corporation 469,543 — 284 — — 1,103 POSCO Canada Ltd. 275 — 148,528 — — — POSCO Asia Co., Ltd. 1,758,080 1,373 403,174 247 939 3,602 Qingdao Pohang Stainless Steel Co., Ltd. 135,405 — — — — 525 POSCO JAPAN Co., Ltd. 1,112,489 128 23,217 3,744 345 3,841 POSCO-VIETNAM Co., Ltd. 226,063 445 — — — — POSCO MEXICO S.A. DE C.V. 274,210 462 — — — — POSCO Maharashtra Steel Private Limited 355,829 2,613 — — — 93 POSCO(Suzhou) Automotive Processing Center Co., Ltd. 149,911 — — — — — Others 766,263 22,717 207,601 62,202 212,344 145,562 11,160,350 125,892 2,214,877 496,841 592,579 380,144 Associates and joint ventures SeAH Changwon Integrated Special Steel 28 — 1,095 — 627 — POSCO PLANTEC Co., Ltd. 2,245 48 3,533 244,898 16,812 8,146 SNNC 6,004 1,042 487,395 — — 2 POSCO-SAMSUNG-Slovakia Processing center 44,686 — — — — — KOBRASCO — 29,297 — — — — Others 26,625 13,122 175,246 — — — 79,588 43,509 667,269 244,898 17,439 8,148 ￦ 11,239,938 169,401 2,882,146 741,739 610,018 388,292 (*1) Sales and others mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System. (*4) During the year ended December 31, 2016, it was merged into POSCO Processing & Service. 2) For the year ended December 31, 2017 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 3,328 71 — 151,639 32 18,352 POSCO Processing & Service 298,781 1 113,628 4,595 8,309 404 POSCO COATED & COLOR STEEL Co., Ltd. 417,369 3,533 — — 8,483 106 POSCO ICT (*3) 1,697 5,097 — 315,748 29,773 183,226 eNtoB Corporation 1 30 330,921 8,215 139 26,023 POSCO CHEMTECH 359,862 33,076 479,896 23,043 296,296 6,860 POSCO ENERGY CO., LTD. 179,966 1,456 — — — 2 POSCO DAEWOO Corporation 5,214,127 35,182 550,258 221 44,108 1,948 POSCO Thainox Public Company Limited 218,005 9,780 10,168 — — — POSCO America Corporation 345,225 — 90 — — 1,776 POSCO Canada Ltd. 439 690 278,915 — — — POSCO Asia Co., Ltd. 1,949,354 1,454 365,025 337 1,625 4,982 Qingdao Pohang Stainless Steel Co., Ltd. 161,803 — — — — 176 POSCO JAPAN Co., Ltd. 1,436,159 20 26,256 621 — 44,829 POSCO-VIETNAM Co., Ltd. 212,883 — — — — 7 POSCO MEXICO S.A. DE C.V. 276,387 — — — — 1,749 POSCO Maharashtra Steel Private Limited 467,206 — — — — 65 POSCO (Suzhou) Automotive Processing Center Co., Ltd. 192,467 — — — — — Others 932,048 10,073 262,828 25,270 240,687 118,665 12,667,107 100,463 2,417,985 529,689 629,452 409,170 Associates and joint ventures POSCO PLANTEC Co., Ltd. 2,947 112 5,487 300,041 20,718 19,763 SNNC 6,734 712 554,151 — — 4 POSCO-SAMSUNG-Slovakia Processing Center 52,779 — — — — — Roy Hill Holdings Pty Ltd — — 697,096 — — — CSP — Compania Siderurgica do Pecem 7,384 — 159,501 — — — Others 14,943 52,583 79,103 — — 3 84,787 53,407 1,495,338 300,041 20,718 19,770 ￦ 12,751,894 153,870 3,913,323 829,730 650,170 428,940 (*1) Sales and others mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System 3) For the year ended December 31, 2018 Sales and others (*1) Purchase and others (*2) Sales Others Purchase of Purchase of Outsourced Others (in millions of Won) Subsidiaries (*3) POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 7,827 97 — 322,924 47 36,428 POSCO COATED & COLOR STEEL Co., Ltd. 476,105 2,725 — — 9,211 1,434 POSCO ICT (*4) 2,624 7,479 — 341,472 34,376 196,252 eNtoB Corporation 12 60 377,198 27,508 390 31,455 POSCO CHEMTECH 417,957 35,762 531,452 21,730 319,868 2,802 POSCO ENERGY CO., LTD. 206,638 1,445 — — — — POSCO DAEWOO Corporation 5,835,226 42,888 690,345 — 57,624 4,318 POSCO Thainox Public Company Limited 299,450 5,335 10,115 — — 71 POSCO America Corporation 336,366 — — — — 2,486 POSCO Canada Ltd. — 2,155 300,982 — — — POSCO Asia Co., Ltd. 1,857,665 253 536,280 650 2,449 6,524 Qingdao Pohang Stainless Steel Co., Ltd. 188,252 7 — — — 34 POSCO JAPAN Co., Ltd. 1,353,313 6 25,773 4,204 — 5,411 POSCO-VIETNAM Co., Ltd. 273,573 156 — — — 8 POSCO MEXICO S.A. DE C.V. 299,276 17 — — — 35 POSCO Maharashtra Steel Private Limited 563,618 584 — — — 156 POSCO (Suzhou) Automotive Processing Center Co., Ltd. 196,095 — 2,616 — — 5 Others (*5) 1,158,122 44,098 456,804 31,787 264,060 140,869 13,472,119 143,067 2,931,565 750,275 688,025 428,288 Associates and joint ventures (*3) POSCO PLANTEC Co., Ltd. 10,904 240 3,166 215,023 24,192 10,257 SNNC 5,105 4,108 558,425 — — 80 POSCO-SAMSUNG-Slovakia Processing Center 61,981 — — — — — Roy Hill Holdings Pty Ltd — — 810,196 — — — Others 14,199 54,747 64,335 — — 6 92,189 59,095 1,436,122 215,023 24,192 10,343 ￦ 13,564,308 202,162 4,367,687 965,298 712,217 438,631 (*1) Sales and others are mainly consist of sales of steel products to subsidiaries, associates and joint ventures. (*2) Purchases and others are mainly consist of subsidiaries’ purchases of construction services and purchases of raw materials to manufacture steel products. (*3) As of December 31, 2018, the Company provided guarantees to related parties (Note 38). (*4) Others (purchase) mainly consist of service fees related to maintenance and repair of ERP System. (*5) During the year ended December 31, 2018, the Company made loans of ￦
Related Account Balances With Related Parties	(b) The related account balances of significant transactions between the controlling company and related companies as of December 31, 2017 and 2018 are as follows: 1) December 31, 2017 Receivables Payables Trade accounts and Others Total Trade accounts and Accounts Others Total (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 2 2,908 2,910 — 21,965 674 22,639 POSCO COATED & COLOR STEEL Co., Ltd. 58,184 324 58,508 — 5 504 509 POSCO ICT 55 217 272 1,458 72,586 27,009 101,053 eNtoB Corporation — — — 12,252 31,899 20 44,171 POSCO CHEMTECH 61,810 3,589 65,399 51,774 20,313 17,568 89,655 POSCO ENERGY CO., LTD. 33,239 1,673 34,912 — — 1,425 1,425 POSCO DAEWOO Corporation 483,915 12,739 496,654 10,213 2,145 5,794 18,152 POSCO Thainox Public Company Limited 57,826 — 57,826 1,204 — — 1,204 POSCO America Corporation 5,365 — 5,365 — — — — POSCO Asia Co., Ltd. 404,857 541 405,398 9,811 24 — 9,835 Qingdao Pohang Stainless Steel Co., Ltd. 31,693 — 31,693 — — — — POSCO MEXICO S.A. DE C.V. 55,695 530 56,225 — — — — POSCO Maharashtra Steel Private Limited 392,630 5,733 398,363 — — — — Others 384,385 49,403 433,788 15,038 59,575 31,118 105,731 1,969,656 77,657 2,047,313 101,750 208,512 84,112 394,374 Associates and joint ventures POSCO PLANTEC Co., Ltd. 1,946 9 1,955 3,842 15,723 — 19,565 SNNC 648 61 709 49,506 3 — 49,509 Others 8,350 904 9,254 824 — — 824 10,944 974 11,918 54,172 15,726 — 69,898 ￦ 1,980,600 78,631 2,059,231 155,922 224,238 84,112 464,272 2) December 31, 2018 Receivables Payables Trade accounts and Others Total Trade accounts and Accounts Others Total (in millions of Won) Subsidiaries POSCO ENGINEERING & CONSTRUCTION CO., LTD. ￦ 57 5,181 5,238 — 52,775 438 53,213 POSCO COATED & COLOR STEEL Co., Ltd. 55,598 317 55,915 — 25 1,194 1,219 POSCO ICT — 229 229 1,572 112,960 8,717 123,249 eNtoB Corporation — — — 10,860 22,072 11 32,943 POSCO CHEMTECH 40,258 3,883 44,141 19,911 58,725 19,012 97,648 POSCO ENERGY CO., LTD. 22,163 1,700 23,863 — — 1,425 1,425 POSCO DAEWOO Corporation 437,554 1,056 438,610 161 1,881 5,304 7,346 POSCO Thainox Public Company Limited 71,189 — 71,189 467 71 — 538 POSCO America Corporation 14,338 — 14,338 — 221 — 221 POSCO Asia Co., Ltd. 480,205 1,047 481,252 7,839 — — 7,839 Qingdao Pohang Stainless Steel Co., Ltd. 52,037 — 52,037 — — — — POSCO MEXICO S.A. DE C.V. 101,179 218 101,397 — — — — POSCO Maharashtra Steel Private Limited 390,413 1,428 391,841 — — — — Others 379,950 54,407 434,357 33,183 36,591 85,745 155,519 2,044,941 69,466 2,114,407 73,993 285,321 121,846 481,160 Associates and joint ventures POSCO PLANTEC Co., Ltd. 249 10 259 3,275 34,803 — 38,078 SNNC 541 61 602 22,188 — — 22,188 Roy Hill Holdings Pty Ltd — — — 22,997 — — 22,997 Others 918 910 1,828 217 76 — 293 1,708 981 2,689 48,677 34,879 — 83,556 ￦ 2,046,649 70,447 2,117,096 122,670 320,200 121,846 564,716
Company, excluding the controlling company [member]
Statement [LineItems]
Significant Transactions With Related Parties	(c) Significant transactions between the Company, excluding the controlling company, and related companies for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) December 31, 2016 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures SeAH Changwon integrated Special Steel ￦ 16,294 — 22,029 — POSCO PLANTEC Co., Ltd. 21,659 5 3,335 5,912 New Songdo International City Development, LLC 226,042 — — 14 SNNC 29,330 — 21,479 9,494 Posco e&c Songdo International Building 4,245 — — 16,219 Chun-cheon Energy Co., Ltd 288,307 — — — Noeul Green Energy 107,268 — — — Incheon-Gimpo Expressway Co., Ltd. 102,183 — — — VSC POSCO Steel Corporation 43,650 47 479 — USS-POSCO 287,072 — 1,195 — CSP — Compania Siderurgica do Pecem 157,814 — — — Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 61,844 — 57,179 — LLP POSUK Titanium — — 14,575 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — — 24,365 — POS-SEAH 15,759 — — — PT. Batutua Tembaga Raya — — 13,079 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 31,711 — 65 — Zhangjiagang Pohang Refractories Co., Ltd. 250 14 364 2,472 Sebang Steel — — 26,276 — SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. 157,886 — 3,535 — DMSA/AMSA — — 72,582 — South-East Asia Gas Pipeline Company Ltd. — 87,973 — — Others 195,139 11,184 16,664 1,801 ￦ 1,746,453 99,223 277,201 35,912 2) December 31, 2017 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 19,513 — 98 8,113 New Songdo International City Development, LLC 223,567 13,207 — 49 SNNC 26,288 — 3,578 17,985 Chun-cheon Energy Co., Ltd 42,147 — — — Noeul Green Energy 11,863 — — 2,178 VSC POSCO Steel Corporation 19,404 — 188 — USS-POSCO 26,899 107 2,222 — CSP — Compania Siderurgica do Pecem 241,299 — 101,018 21,154 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 38,484 — 47,241 — LLP POSUK Titanium — — 3,972 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. 4 — 20,145 — POS-SEAH 20,004 — — — PT. Batutua Tembaga Raya — — 21,024 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 34,088 — 192 — Zhangjiagang Pohang Refractories Co., Ltd. — — 87 1,632 Sebang Steel 441 — 23,778 — SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN’L TRADING CO., LTD. 43,764 — — — DMSA/AMSA — 99 47,092 — South-East Asia Gas Pipeline Company Ltd. — 62,423 — — Others 272,107 43,126 19,520 19,483 ￦ 1,019,872 118,962 290,155 70,594 3) December 31, 2018 Sales and others Purchase and others Sales Others Purchase of Others (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 19,394 — 83 24,103 New Songdo International City Development, LLC 30,997 53,316 — 97 SNNC 66,075 128 2,395 71,421 Chun-cheon Energy Co., Ltd 25,693 — — — Noeul Green Energy 6,444 — — 587 VSC POSCO Steel Corporation 12,504 — 2,314 — USS-POSCO — — 2,595 — CSP — Compania Siderurgica do Pecem 239,922 9,678 346,602 26,324 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 46,538 — 62,851 — LLP POSUK Titanium — — 944 — BX STEEL POSCO Cold Rolled Sheet Co., Ltd. — — 10,572 — POS-SEAH 12,244 — — — PT. Batutua Tembaga Raya — 168 15,663 — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 30,417 — 249 — Sebang Steel — — 13,571 — DMSA/AMSA — — 46,293 — South-East Asia Gas Pipeline Company Ltd. — 50,789 — — Others 359,124 62,375 19,192 50,918 ￦ 849,352 176,454 523,324 173,450
Related Account Balances With Related Parties	(d) The related account balances of significant transactions between the Company, excluding the controlling company, and related companies as of December 31, 2017 and December 31, 2018 are as follows: 1) December 31, 2017 Receivables (*1) Payables Trade accounts and Loan Others Total Trade accounts and Others Total (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 2,287 — 5 2,292 3,442 5,595 9,037 New Songdo International City Development, LLC 484,038 282,775 1,696 768,509 — 7,146 7,146 Chun-cheon Energy Co., Ltd — — 21 21 — 9,617 9,617 Nickel Mining Company SAS — 59,668 118 59,786 — — — CSP — Compania Siderurgica do Pecem 380,180 — 13,443 393,623 — 29,700 29,700 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 2,108 5,357 6 7,471 2,449 — 2,449 PT. Batutua Tembaga Raya 24 29,048 — 29,072 — — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 8,067 5,357 32 13,456 107 — 107 DMSA/AMSA — 69,713 4,443 74,156 — — — South-East Asia Gas Pipeline Company Ltd. — 229,880 — 229,880 — — — Others 135,128 134,506 6,889 276,523 1,873 2,531 4,404 ￦ 1,011,832 816,304 26,653 1,854,789 7,871 54,589 62,460 (*1) As of December 31, 2017, the Company recognizes bad-debt ￦ 2) December 31, 2018 Receivables (*1) Payables Trade accounts and Loan Others Total Trade accounts and Others Total (in millions of Won) Associates and joint ventures POSCO PLANTEC Co., Ltd. ￦ 3,593 — 6 3,599 6,160 217 6,377 New Songdo International City Development, LLC 233,157 — — 233,157 — — — Chun-cheon Energy Co., Ltd — — — — — 1,758 1,758 POSPower Co., Ltd 13,703 — — 13,703 — 66,856 66,856 Nickel Mining Company SAS — 59,664 118 59,782 — — — CSP — Compania Siderurgica do Pecem 364,190 — 9,669 373,859 62,578 — 62,578 Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd 10,836 — — 10,836 2,101 — 2,101 PT. Batutua Tembaga Raya — 35,100 171 35,271 — — — POSCO SeAH Steel Wire (Nantong) Co., Ltd. 6,274 3,354 27 9,655 66 — 66 DMSA/AMSA — 64,297 — 64,297 — — — South-East Asia Gas Pipeline Company Ltd. — 191,107 — 191,107 — — — Others 75,382 136,117 13,071 224,570 7,768 5,363 13,131 ￦ 707,135 489,639 23,062 1,219,836 78,673 74,194 152,867 (*1) As of December 31, 2018, the Company recognizes bad-debt ￦

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Contingent liabilities on outstanding guarantees [member]
Statement [LineItems]
Summary of Contingent Liabilities	Contingent liabilities on outstanding guarantees and others provided by the Company as of December 31, 2018 are as follows. Guarantee limit Guarantee amount Guarantor Guarantee beneficiary Financial institution Foreign currency Won Foreign Won (in millions of Won) [The Company] POSCO POSCO Asia Co., Ltd. BOC and others USD 100,000,000 111,810 100,000,000 111,810 POSCO ASSAN TST STEEL INDUSTRY SMBC and others USD 146,527,500 163,832 131,874,750 147,449 POSCO COATED STEEL (THAILAND) CO., LTD. The Great & CO Co., Ltd. (SPC) THB 5,501,000,000 188,959 5,501,000,000 188,959 POSCO Maharashtra Steel Private Limited Export-Import Bank of Korea and others USD 506,853,000 566,712 168,397,800 188,285 POSCO MEXICO S.A. DE C.V. BOA and others USD 160,000,000 178,896 160,000,000 178,896 POSCO SS VINA Co., Ltd. Export-Import Bank of Korea and others USD 354,351,050 396,200 274,570,077 306,996 POSCO-VIETNAM Co., Ltd. SMBC and others USD 156,000,000 174,424 156,000,000 174,424 PT. KRAKATAU POSCO Export-Import Bank of Korea and others USD 1,350,300,000 1,509,770 1,097,236,405 1,226,821 POSCO DAEWOO Corporation Daewoo Global Development. Pte., Ltd Export-Import Bank of Korea and others USD 196,017,000 219,167 196,017,000 219,167 Daewoo Power PNG Ltd. Export-Import Bank of Korea USD 47,600,000 53,222 47,600,000 53,222 POSCO ASSAN TST STEEL INDUSTRY ING and others USD 14,652,750 16,383 14,652,750 16,383 POSCO DAEWOO INDIA PVT., LTD. Shinhan Bank and others USD 149,400,000 167,044 77,990,903 87,203 PT. Bio Inti Agrindo Export-Import Bank of Korea and others USD 125,125,000 139,902 125,125,000 139,902 KEB Hana Bank IDR 150,000,000,000 11,520 150,000,000,000 11,520 Golden Lace DAEWOO Company Limited Shinhan Bank USD 9,000,000 10,063 6,000,000 6,708 POSCO DAEWOO CHINA CO., LTD Mizuho USD 8,000,000 8,945 7,290,000 8,151 Songdo Posco family Housing SHINYOUNG SECURITIES CO., LTD. KRW 10,000 10,000 — — POSCO ENGINEERING & CONSTRUCTION CO., LTD. POSCO E&C Vietnam Co., Ltd. Export-Import Bank of Korea and others USD 47,000,000 52,551 47,000,000 52,551 HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd. Woori bank and others USD 148,000,000 165,479 142,000,000 158,770 POSCO Engineering and Construction India Private Limited Woori bank USD 2,100,000 2,348 2,100,000 2,348 KEB Hana Bank INR 104,000,000 1,663 9,000,000 144 PT. POSCO E&C INDONESIA POSCO Asia Co., Ltd. and others USD 10,900,000 12,187 10,900,000 12,187 Daewoo Global Development. Pte., Ltd SMBC and others USD 163,633,000 182,958 163,633,000 182,958 Songdo Posco family Housing SHINYOUNG SECURITIES CO., LTD. KRW 10,000 10,000 — — POSCO ICT PT.POSCO ICT INDONESIA POSCO Asia Co., Ltd. USD 1,500,000 1,677 1,500,000 1,677 POSCO CHEMTECH PT.Krakatau Posco Chemtech Calcination POSCO Asia Co., Ltd. USD 15,200,000 16,995 14,400,000 16,101 POSCO COATED & COLOR STEEL Co., Ltd. Myanmar POSCO C&C Company, Limited. POSCO Asia Co., Ltd. USD 13,986,947 15,639 13,986,947 15,639 POSCO ENERGY CO., LTD. PT. KRAKATAU POSCO ENERGY Export-Import Bank of Korea and others USD 193,900,000 216,800 121,231,918 135,549 POSCO Asia Co., Ltd. POSCO SINGAPORE LNG TRADING PTE. LTD. SMBC USD 40,000,000 44,724 40,000,000 44,724 [Associates and joint ventures] POSCO CSP — Compania Siderurgica do Pecem Export-Import Bank of Korea and others USD 420,000,000 469,602 392,956,955 439,365 BNDES BRL 464,060,000 133,686 462,554,370 133,253 LLP POSUK Titanium SMBC USD 15,000,000 16,772 15,000,000 16,772 Nickel Mining Company SAS SMBC EUR 46,000,000 58,841 46,000,000 58,841 POSCO DAEWOO Corporation GLOBAL KOMSCO Daewoo LLC ICBC USD 8,225,000 9,196 8,225,000 9,196 POSCO ENGINEERING & CONSTRUCTION CO., LTD. New Songdo International City Development, LLC Others KRW 440,000 440,000 432,000 432,000 UITrans LRT Co., Ltd. Kookmin Bank and others KRW 20,740 20,740 3,766 3,766 Chun-cheon Energy Co., Ltd Kookmin Bank and others KRW 11,600 11,600 941 941 Pohang E&E Co., Ltd Heungkuk Life Insurance Co., Ltd. KRW 6,500 6,500 — — JB CLARK HILLS Korea Investment & Securities Co., Ltd. KRW 40,000 40,000 30,000 30,000 POSCO ICT Incheon-Gimpo Expressway Co, Ltd. KDB Bank KRW 100,000 100,000 100,000 100,000 UITrans LRT Co., Ltd. Kookmin Bank KRW 76,000 76,000 76,000 76,000 POSCO CHEMTECH KRAKATAU POS-CHEM DONG-SUH KEB Hana Bank USD 1,140,000 1,274 791,667 885 POSCO(Suzhou) Automotive Processing Center Co., Ltd. POS-InfraAuto KDB Bank USD 780,000 872 780,000 872 [Others] POSCO DAEWOO Corporation Ambatovy Project Investments Ltd. and others Export-Import Bank of Korea USD 87,272,727 97,580 12,030,434 13,451 POSCO ENGINEERING & CONSTRUCTION CO., LTD. Ecocity CO., LTD and others Others KRW 1,524,314 1,524,314 545,893 545,893 POSCO ICT SMS Energy and others KEB Hana Bank and others KRW 78,791 78,791 60,519 60,519 Hyochun CO., LTD KYOBO SECURITIES CO., LTD. KRW 39,575 39,575 39,575 39,575 BTL Enterprise and others Kyobo Life Insurance Co., Ltd and others KRW 1,165,352 1,165,352 1,165,352 1,165,352 POSCO AUSTRALIA PTY LTD Department of Trade and Investment (NSW Government) and others Woori bank and others AUD 26,147,711 20,599 26,147,711 20,599 USD 4,492,463,974 5,023,024 3,549,290,606 3,968,462 KRW 3,522,872 3,522,872 2,454,046 2,454,046 IDR 150,000,000,000 11,520 150,000,000,000 11,520 INR 104,000,000 1,663 9,000,000 144 THB 5,501,000,000 188,959 5,501,000,000 188,959 EUR 46,000,000 58,841 46,000,000 58,841 AUD 26,147,711 20,599 26,147,711 20,599 BRL 464,060,000 133,686 462,554,370 133,253
Litigations in progress [member]
Statement [LineItems]
Summary of Contingent Liabilities	As of December 31, 2018, litigations in progress that POSCO and certain subsidiaries are defendants in legal actions arising from the normal course of business are as follows: Company Legal Claim amount Won Description (in millions of Won, in thousands of foreign currencies) POSCO 27 KRW 75,218 75,218 Lawsuit on claim for employee right and others (*1) POSCO DAEWOO Corporation 1 CAD 79,000 64,808 Lawsuit on claim for damages 3 INR 4,518,694 72,254 Lawsuit on claim for payment on guarantees and others (*1) 10 KRW 20,049 20,049 Litigation for confirmation of deposit bond and others 5 USD 28,763 32,160 Lawsuit on claim for damages and others 1 PKR 124,775 1,003 Lawsuit on claim for damages POSCO ENGINEERING & CONSTRUCTION., LTD. 120 KRW 442,812 442,812 Lawsuit on claim for damages and others (*1) POSCO ICT 1 BRL 10,182 2,933 Lawsuit on revocation of claim for damage 11 KRW 6,452 6,452 Lawsuit on claim for damages and others 1 USD 1,881 2,103 Lawsuit on claim for damages POSCO A&C 8 KRW 2,752 2,752 Lawsuit on claim for payment on construction and others POSCO ENERGY CO., LTD. 3 KRW 3,039 3,039 Lawsuit on claim for damages and others POSCO E&C CHINA CO., LTD. 3 CNY 44,446 7,234 Lawsuit over contract dispute and others POSCO COATED & COLOR STEEL Co., Ltd. 1 KRW 1,400 1,400 Lawsuit on claim for payment POSCO ENGINEERING 2 THB 509,191 17,491 Lawsuit on claim for payment on construction and others PT. KRAKATAU POSCO 1 IDR 211,407,872 16,236 Lawsuit on claim for payment on construction POSCO E&C Vietnam Co., Ltd. 1 USD 3,894 4,354 Lawsuit on claim for payment on construction POSCO-China Qingdao 2 CNY 6,774 1,103 Lawsuit over contract dispute and others POSCO-Malaysia SDN. BHD. 1 MYR — — Lawsuit on claim for infringement of right Pos-Sea 1 USD 12,051 13,474 Lawsuit over contract dispute POSCO INDIA HOLDINGS PRIVATE 1 INR 220,000 3,518 Lawsuit over contract dispute POSCO TNPC Otomotiv Celik 8 TRY 102 22 Lawsuit over industrial accidents and others POSCO India Steel Distribution Center Private Ltd. 1 INR 223,795 3,578 Lawsuit on claim for tax restitution POSCO(Dalian) 1 CNY 4,240 690 Lawsuit over contract dispute Brazil Sao Paulo Steel 3 BRL 4,671 1,346 Lawsuit on claim for labor and others POSCO ENGINEERING & 148 BRL 156,011 44,944 Lawsuit on claim for payment on construction and others POSCO ASSAN TST STEEL INDUSTRY 1 TRY 4,870 1,027 Lawsuit on compensation HONG KONG POSCO E&C 1 KRW 3,305 3,305 Lawsuit on claim for payment (*1) The Company made a reliable estimate in 122 lawsuits by considering the possibility and amount of outflow of resources and recognized ￦

Additional Information of Cas_2

Additional Information of Cash Flow Statements (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Changes in Operating Assets and Liabilities	(a) Changes in operating assets and liabilities for the years ended December 31, 2016, 2017 and 2018 were as follows: IFRS 2016 2017 2018 (in millions of Won) Trade accounts and notes receivable ￦ 63,075 17,806 Other receivables 191,591 113,740 (20,786 ) Inventories (889,998 ) (1,435,170 ) (1,451,009 ) Other current assets (287,377 ) 110,688 1,118 Other non-current 33,584 12,455 5,974 Trade accounts and notes payable 769,337 (607,999 ) 379,742 Other payables (179,174 ) (26,922 ) (111,893 ) Other current liabilities 2,490 338,273 (199,981 ) Provisions (124,884 ) (145,763 ) (116,790 ) Payments of severance benefits (278,278 ) (185,220 ) (189,165 ) Plan assets (138,854 ) 3,815 (245,214 ) Other non-current 223,574 (82,605 ) (175,528 ) ￦ (1,841,633 ) (2,105,726 )
Changes in Liabilities Arising from Financial Activities	(b) Changes in liabilities arising from financial activities for the year ended December 31, 2017 and 2018 were as follows: 1) December 31, 2017 Liabilities Derivatives that hedge Short-term Long-term Dividend Finance (in millions of Won) Beginning ￦ 14,725,271 7,770 114,409 (52,373 ) Changes from financing cash flows 558,083 (1,410,033 ) (931,232 ) (10,536 ) — Changes arising from obtaining or losing control of subsidiaries or other business (12,469 ) 3,299 — — — The effect of changes in foreign exchange rates (350,523 ) (435,170 ) — (10,855 ) — Changes in fair values — — — — 171,693 Other changes: Decrease in retained earnings — — 863,579 — — Decrease in non-controlling — — 67,096 — — Amortization of discount on debentures issued — 5,472 — — — Ending ￦ 12,888,839 7,213 93,018 119,320 2) December 31, 2018 Liabilities Derivatives Short-term Long-term Dividend Finance (in millions of Won) Beginning ￦ 12,888,839 7,213 93,018 119,320 Changes from financing cash flows (854,554 ) (373,862 ) (770,099 ) (14,955 ) (17,237 ) Changes arising from obtaining or losing (342 ) — — — — The effect of changes in foreign exchange rates 167,858 200,308 (5,573 ) (7,766 ) — Changes in fair values — — — — (58,666 ) Other changes: — Decrease in retained earnings — — 704,444 — — Decrease in non-controlling — — 72,688 — — Amortization of discount on debentures issued — 6,205 — — — Increase in finance lease assets — — — 24,457 — Ending ￦ 12,721,490 8,673 94,754 43,417

Operating Segments and Geogra_2

Operating Segments and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2018
Text block [abstract]
Information about Reportable Segments	(b) Information about reportable segments as of and for the years ended December 31, 2016, 2017 and 2018 were as follows: 1) As of and for the year ended December 31, 2016 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 26,844,154 16,774,078 6,768,348 2,696,933 53,083,513 Internal revenues 16,062,016 9,646,026 713,703 2,379,945 28,801,690 Including inter segment revenue 8,992,783 5,296,847 557,526 2,285,128 17,132,284 Total revenues 42,906,170 26,420,104 7,482,051 5,076,878 81,885,203 Interest income 126,210 40,424 65,256 13,564 245,454 Interest expenses (459,345 ) (70,841 ) (102,292 ) (126,523 ) (759,001 ) Depreciation and amortization (2,788,535 ) (165,863 ) (57,719 ) (264,299 ) (3,276,416 ) Impairment loss on property, plant and equipment and others (99,165 ) (45,995 ) (9,426 ) (88,696 ) (243,282 ) Impairment loss on available-for-sale (225,225 ) (28,988 ) (35,331 ) (24,902 ) (314,446 ) Share of profit or loss of investment in associates and joint ventures (211,084 ) (53,586 ) (283,833 ) (6,369 ) (554,872 ) Income tax expense (495,874 ) (18,629 ) 107,520 (56,026 ) (463,009 ) Segment profit (loss) 1,511,383 53,244 (1,403,712 ) (25,889 ) 135,026 Segment assets 69,914,939 13,580,179 9,501,046 8,529,600 101,525,764 Investment in subsidiaries, associates and joint ventures 16,109,360 1,100,973 795,445 1,200,295 19,206,073 Acquisition of non-current 2,334,842 249,597 25,533 191,715 2,801,687 Segment liabilities 20,292,764 10,134,170 6,780,380 4,709,689 41,917,003 2) As of and for the year ended December 31, 2017 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 30,230,368 20,802,207 6,886,606 2,735,919 60,655,100 Internal revenues 17,381,010 14,075,996 398,924 2,548,674 34,404,604 Including inter segment revenue 12,004,614 8,043,643 329,215 2,446,029 22,823,501 Total revenues 47,611,378 34,878,203 7,285,530 5,284,593 95,059,704 Interest income 128,827 32,799 100,922 17,940 280,488 Interest expenses (422,357 ) (121,967 ) (112,983 ) (100,656 ) (757,963 ) Depreciation and amortization (2,856,133 ) (206,490 ) (42,123 ) (255,620 ) (3,360,366 ) Impairment loss on property, plant and equipment and others (149,840 ) (140,839 ) (37,476 ) (8,564 ) (336,719 ) Impairment loss on available-for-sale (95,261 ) — (18,637 ) (13,421 ) (127,319 ) Share of profit or loss of investment in associates and joint ventures 8,352 — (8,555 ) (1,518 ) (1,721 ) Income tax expense (977,853 ) (109,710 ) (109,961 ) (77,172 ) (1,274,696 ) Segment profit 2,790,855 112,661 24,545 232,700 3,160,761 Segment assets 70,017,816 14,139,098 8,609,753 8,776,090 101,542,757 Investment in subsidiaries, associates and joint ventures 16,116,654 1,134,798 668,392 1,193,895 19,113,739 Acquisition of non-current 2,033,184 286,185 99,190 251,665 2,670,224 Segment liabilities 19,057,249 10,386,294 5,744,693 4,620,902 39,809,138 3) As of and for the year ended December 31, 2018 Steel Trading Construction Others Total (in millions of Won) External revenues ￦ 32,358,009 22,407,717 6,769,410 3,442,641 64,977,777 Internal revenues 18,063,213 15,911,138 551,324 2,755,176 37,280,851 Including inter segment revenue 12,496,287 8,743,666 465,057 2,639,561 24,344,571 Total revenues 50,421,222 38,318,855 7,320,734 6,197,817 102,258,628 Interest income 199,016 36,437 115,019 23,454 373,926 Interest expenses (468,681 ) (189,165 ) (111,101 ) (94,613 ) (863,560 ) Depreciation and amortization (2,812,666 ) (210,493 ) (36,840 ) (265,416 ) (3,325,415 ) Impairment loss on property, plant and equipment and others (1,057,474 ) (86,085 ) (82,521 ) (117,280 ) (1,343,360 ) Share of profit or loss of investment in associates and joint ventures (733,879 ) (160,085 ) (155,371 ) — (1,049,335 ) Income tax expense (1,307,292 ) (52,914 ) (238,441 ) (65,611 ) (1,664,258 ) Segment profit 1,268,313 49,264 234 13,608 1,331,419 Segment assets 70,976,493 15,550,854 7,333,221 8,017,433 101,878,001 Investment in subsidiaries, associates and joint ventures 16,099,692 1,379,045 511,230 932,107 18,922,074 Acquisition of non-current 2,239,467 132,017 49,095 232,281 2,652,860 Segment liabilities 20,289,037 11,454,079 4,386,852 4,134,352 40,264,320
Reconciliation of Segment Revenues, Profit or Loss, Assets and Liabilities and Other Significant Items	(c) Reconciliations of total segment revenues, profit or loss, assets and liabilities, and other significant items to their respective consolidated financial statement line items are as follows: 1) Revenues 2016 2017 2018 (in millions of Won) Total revenue for reportable segments ￦ 81,885,203 95,059,704 102,258,628 Elimination of inter-segment revenue (28,801,690 ) (34,404,604 ) (37,280,851 ) Basis difference (*2) (143,742 ) (468,233 ) 176,859 ￦ 52,939,771 60,186,867 65,154,636 2) Profit 2016 2017 2018 (in millions of Won) Total profit (loss) for reportable segments ￦ 135,026 3,160,761 1,331,419 Goodwill and corporate FV adjustments (123,110 ) (84,370 ) (77,756 ) Elimination of inter-segment profits 1,036,253 (102,922 ) 638,401 Income tax expense 384,685 1,206,223 1,670,757 Basis difference (*2) (21,245 ) (84,641 ) 53,195 Profit before income tax expense ￦ 1,411,609 4,095,051 3,616,016 3) Assets 2017 2018 (in millions of Won) Total assets for reportable segments (*1) ￦ 101,542,757 101,878,001 Equity-accounted investees (15,555,972 ) (15,272,243 ) Goodwill and corporate FV adjustments 3,368,333 2,722,115 Elimination of inter-segment assets (10,330,159 ) (11,079,608 ) Basis difference (*2) 760,670 528,726 ￦ 79,785,629 78,776,991 (*1) As segment assets and liabilities are determined based on separate financial statements, for subsidiaries which are in a different segment from that of its immediate parent company, their carrying amount in separate financial statements is eliminated upon consolidation. In addition, adjustments are made to adjust the amount of investment in associates and joint ventures from the amount reflected in segment assets to that determined using equity method in consolidated financial statements. 4) Liabilities 2017 2018 (in millions of Won) Total liabilities for reportable segments ￦ 39,809,138 40,264,320 Corporate FV adjustments 483,693 321,320 Elimination of inter-segment liabilities (8,731,880 ) (9,096,926 ) Basis difference (*2) 897,953 615,663 ￦ 32,458,904 32,104,377 5) Other significant items a) December 31, 2016 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 245,454 — (62,979 ) — 182,475 Interest expenses (759,001 ) (807 ) 101,082 — (658,726 ) Depreciation and amortization (3,276,416 ) (104,949 ) 167,518 — (3,213,847 ) Share of profit or loss of investment in associates (554,872 ) (38,732 ) 504,927 — (88,677 ) Income tax expense (463,009 ) 21,945 56,379 5,141 (379,544 ) Impairment loss on property, plant and equipment and others (243,282 ) — (125,657 ) — (368,939 ) Impairment loss on available-for-sale (314,446 ) — 66,042 — (248,404 ) ￦ (5,365,572 ) (122,543 ) 707,312 5,141 (4,775,662 ) b) December 31, 2017 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 280,488 — (68,037 ) — 212,451 Interest expenses (757,963 ) 1,304 103,544 — (653,115 ) Depreciation and amortization (3,360,366 ) (106,195 ) 169,141 — (3,297,420 ) Share of profit or loss of investment in associates (1,721 ) — 12,261 — 10,540 Income tax expense (1,274,696 ) 21,270 47,203 20,483 (1,185,740 ) Impairment loss on property, plant and equipment and others (336,719 ) (867 ) 34,619 — (302,967 ) Impairment loss on available-for-sale (127,319 ) — 4,105 — (123,214 ) ￦ (5,578,296 ) (84,488 ) 302,836 20,483 (5,339,465 ) c) December 31, 2018 Total Corporate FV Elimination of inter-segment Basis (*2) Consolidated (in millions of Won) Interest income ￦ 373,926 — (36,668 ) — 337,258 Interest expenses (863,560 ) 1,035 121,229 — (741,296 ) Depreciation and amortization (3,325,415 ) (103,932 ) 161,718 — (3,267,629 ) Share of profit or loss of investment in associates (1,049,335 ) — 1,161,970 — 112,635 Income tax expense (1,664,258 ) 25,921 (32,420 ) (12,873 ) (1,683,630 ) Impairment loss on property, plant and equipment and others (1,343,360 ) (779 ) (107,258 ) — (1,451,397 ) ￦ (7,872,002 ) (77,755 ) 1,268,571 (12,873 ) (6,694,059 ) (*2) Basis difference is related to the difference in recognizing revenue and expenses in connection with development and sale of certain residential real estate between the report reviewed by the CEO and the consolidated financial statements.
Revenue and Non-current Assets by Geographic Area	(d) Revenue by geographic area for the years ended December 31, 2016, 2017 and 2018 was as follows: 2016 2017 2018 (in millions of Won) Domestic ￦ 34,883,941 38,882,220 41,671,930 Japan 1,892,022 2,200,405 2,084,061 China 5,908,046 6,731,214 6,945,266 Indonesia 908,361 1,266,572 1,592,046 Asia-other 4,741,482 6,483,981 7,312,486 North America 1,899,291 1,725,120 1,834,534 Others 2,850,370 3,365,588 3,537,454 53,083,513 60,655,100 64,977,777 Basis difference (143,742 ) (468,233 ) 176,859 ￦ 52,939,771 60,186,867 65,154,636 In presenting information on the basis of geography, segment revenue is based on the geographical location of customers. (e) Non-current 2017 2018 (in millions of Won) Domestic ￦ 30,790,462 28,298,293 Japan 162,328 146,490 China 1,284,561 1,185,828 Indonesia 2,750,084 2,711,032 Asia-other 2,516,715 2,356,904 North America 277,249 173,914 Others 1,119,319 1,245,252 ￦ 38,900,718 36,117,713

General Information - Additiona

General Information - Additional Information (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)EntitySteel_PlantOffice	Dec. 31, 2017KRW (₩)	Dec. 31, 2016KRW (₩)
Disclosure of general information [Line Items]
Number of associates and joint ventures | Entity	126
Number of operational steel plants | Steel_Plant	2
Increase in ownership interests in subsidiaries	₩ (2,151)	₩ 163,707	₩ (7,894)
Dividends paid by subsidiaries	75,830	70,087	₩ 100,862
POSCO DAEWOO Corporation POSMATE and others [member]
Disclosure of general information [Line Items]
Increase in ownership interests in subsidiaries	₩ 16,288
POSCO Gulf SFC LLC and others [member]
Disclosure of general information [Line Items]
Increase in ownership interests in subsidiaries		₩ 1,497
Domestic [member]
Disclosure of general information [Line Items]
Number of subsidiaries | Entity	36
Foreign [member]
Disclosure of general information [Line Items]
Number of subsidiaries | Entity	136
Number of operational offices | Office	6
Korea [member]
Disclosure of general information [Line Items]
Number of operational offices | Office	1

General Information - POSCO's S

General Information - POSCO's Shareholders (Detail) - shares	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of details of shareholders [line items]
Number of shares	87,186,835	87,186,835	87,186,835
Ownership (%)	100.00%
National Pension Service [member]
Disclosure of details of shareholders [line items]
Number of shares	9,342,192
Ownership (%)	10.72%
Black rock fund advisors [member]
Disclosure of details of shareholders [line items]
Number of shares	4,549,553
Ownership (%)	5.22%
Nippon Steel & Sumitomo Metal Corporation [member]
Disclosure of details of shareholders [line items]
Number of shares	2,894,712
Ownership (%)	3.32%
GIC private limited [member]
Disclosure of details of shareholders [line items]
Number of shares	2,016,887
Ownership (%)	2.31%
KB Financial Group Inc. and subsidiaries [member]
Disclosure of details of shareholders [line items]
Number of shares	2,001,820
Ownership (%)	2.30%
Other [member]
Disclosure of details of shareholders [line items]
Number of shares	66,381,671
Ownership (%)	76.13%

General Information - POSCO's_2

General Information - POSCO's Shareholders (Parenthetical) (Detail) - ₩ / shares	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Details of Shareholders [abstract]
Number of shares represented by ADRs	0.25
Common share par value	₩ 5,000	₩ 5,000

General Information - Details o

General Information - Details of Consolidated Subsidiaries (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Daewoo Amara Company Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development
Ownership (%)	85.00%	85.00%
Region	Myanmar
Daewoo Amara Company Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	85.00%	85.00%
Daewoo Power and Infra (PTY) Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Electricity
Ownership (%)	100.00%	100.00%
Region	South Africa
Daewoo Power and Infra (PTY) Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSMATE-CHINA CO., LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Business facility maintenance
Ownership (%)	100.00%	100.00%
Region	China
POSMATE-CHINA CO., LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Daewoo Precious Resources Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Resources development
Ownership (%)	70.00%	70.00%
Region	Myanmar
Daewoo Precious Resources Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
POSCO-Mexico Villagran Wire-rod Processing Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	66.75%	66.75%
Region	Mexico
POSCO-Mexico Villagran Wire-rod Processing Center [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	56.75%	56.75%
POSCO-Mexico Villagran Wire-rod Processing Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
POSCO ChengDu Processing Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	43.00%	43.00%
Region	China
POSCO ChengDu Processing Center [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	33.00%	33.00%
POSCO ChengDu Processing Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
POSCO SUZHOU [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
POSCO SUZHOU [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	30.00%	30.00%
POSCO SUZHOU [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
POSCO E&C SMART S DE RL DE CV [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)	100.00%	100.00%
Region	Mexico
POSCO E&C SMART S DE RL DE CV [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO Philippine Manila Processing Center, Inc. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Philippines
POSCO Philippine Manila Processing Center, Inc. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO E&C HOLDINGS CO., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Holding company
Ownership (%)	100.00%	100.00%
Region	Thailand
POSCO E&C HOLDINGS CO., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO E&C (THAILAND) CO., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction and engineering
Ownership (%)	100.00%	100.00%
Region	Thailand
POSCO E&C (THAILAND) CO., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
DAEWOO POWER PNG Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Electricity production
Ownership (%)	100.00%	100.00%
Region	Papua New Guinea
DAEWOO POWER PNG Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT.Krakatau Posco Social Enterprise [member]
Disclosure of subsidiaries [line items]
Principal operations	Social enterprise
Ownership (%)	100.00%	100.00%
Region	Indonesia
PT.Krakatau Posco Social Enterprise [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Ventanas Philippines Construction Inc [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction
Ownership (%)	100.00%	100.00%
Region	Philippines
Ventanas Philippines Construction Inc [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO E&C Mongolia [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction and engineering service
Ownership (%)	100.00%	100.00%
Region	Mongolia
POSCO E&C Mongolia [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO Gulf SFC LLC [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	65.72%	97.76%
Region	United Arab Emirates
POSCO Gulf SFC LLC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	65.72%	97.76%
SANPU TRADING Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Raw material trading
Ownership (%)	70.04%	70.04%
Region	China
SANPU TRADING Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.04%	70.04%
Zhangjiagang BLZ Pohang International Trading [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel Intermediate trade
Ownership (%)	100.00%	100.00%
Region	China
Zhangjiagang BLZ Pohang International Trading [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO RU Limited Liability Company [member]
Disclosure of subsidiaries [line items]
Principal operations	Trade and business development
Ownership (%)	100.00%	100.00%
Region	Russia
POSCO RU Limited Liability Company [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Golden Lace DAEWOO Company Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Rice processing
Ownership (%)	60.00%	60.00%
Region	Myanmar
Golden Lace DAEWOO Company Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	60.00%	60.00%
POSCO ICT-China [member]
Disclosure of subsidiaries [line items]
Principal operations	IT service and DVR business
Ownership (%)	100.00%	100.00%
Region	China
POSCO ICT-China [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Pos-Sea Pte Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel Intermediate trade
Ownership (%)	100.00%	100.00%
Region	Singapore
Pos-Sea Pte Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO Europe Steel Distribution Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Logistics & Steel sales
Ownership (%)	70.00%	70.00%
Region	Slovenia
POSCO Europe Steel Distribution Center [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	50.00%	50.00%
POSCO Europe Steel Distribution Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	20.00%	20.00%
POSCO ENGINEERING (THAILAND) CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction and engineering service
Ownership (%)	100.00%	100.00%
Region	Thailand
POSCO ENGINEERING (THAILAND) CO., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO VST Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Stainless steel sheet manufacturing and sales
Ownership (%)	95.65%	95.65%
Region	Vietnam
POSCO VST Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	95.65%	95.65%
POSCO DAEWOO UKRAINE LLC [member]
Disclosure of subsidiaries [line items]
Principal operations	Grain sales
Ownership (%)	100.00%	100.00%
Region	Ukraine
POSCO DAEWOO UKRAINE LLC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Zhangjiagang Pohang Refactories Co Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Refractory materials sales & furnace maintenance
Ownership (%)	51.00%	51.00%
Region	China
Zhangjiagang Pohang Refactories Co Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	51.00%	51.00%
POSCO Maharashtra Steel Private Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	India
POSCO Maharashtra Steel Private Limited [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO INDIA HOLDINGS PRIVATE LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	95.32%	95.32%
Region	India
POSCO INDIA HOLDINGS PRIVATE LIMITED [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	93.34%	93.34%
POSCO INDIA HOLDINGS PRIVATE LIMITED [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	1.98%	1.98%
POSCO TNPC Otomotiv Celik San. Ve Tic. A.S [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Turkey
POSCO TNPC Otomotiv Celik San. Ve Tic. A.S [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO VIETNAM HOLDINGS CO., LTD (formerly, POSCO VNPC Co., Ltd.) [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	88.83%	88.83%
Region	Vietnam
POSCO VIETNAM HOLDINGS CO., LTD (formerly, POSCO VNPC Co., Ltd.) [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	83.54%	83.54%
POSCO VIETNAM HOLDINGS CO., LTD (formerly, POSCO VNPC Co., Ltd.) [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	5.29%	5.29%
POSCO(Liaoning) Automotive [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
POSCO(Liaoning) Automotive [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	90.00%
POSCO(Liaoning) Automotive [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
POSCO-Indonesia Jakarta Processing Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	85.00%	85.00%
Region	Indonesia
POSCO-Indonesia Jakarta Processing Center [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	65.00%	65.00%
POSCO-Indonesia Jakarta Processing Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	20.00%	20.00%
PT.MRI [member]
Disclosure of subsidiaries [line items]
Principal operations	Mine development
Ownership (%)	65.00%	65.00%
Region	Indonesia
PT.MRI [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	65.00%	65.00%
POSCO TMC INDIA PRIVATE LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	India
POSCO TMC INDIA PRIVATE LIMITED [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO-AAPC [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	97.80%	97.80%
Region	USA
POSCO-AAPC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	97.80%	97.80%
POSCO(Yantai)Automotive Processing Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
POSCO(Yantai)Automotive Processing Center Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	90.00%
POSCO(Yantai)Automotive Processing Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
POSCO India Steel Distribution Center Private Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel logistics
Ownership (%)	100.00%	100.00%
Region	India
POSCO India Steel Distribution Center Private Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO China Dalian Plate Processing Center Co, Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Plate manufacturing and sales
Ownership (%)	91.22%	90.00%
Region	China
POSCO China Dalian Plate Processing Center Co, Ltd [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	79.52%	80.00%
POSCO China Dalian Plate Processing Center Co, Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	11.70%	10.00%
POSCO-South Asia Company Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel sales
Ownership (%)	100.00%	100.00%
Region	Thailand
POSCO-South Asia Company Limited [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO SS-VINA Co., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Vietnam
POSCO SS-VINA Co., Ltd [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT.POSCO ICT INDONESIA [member]
Disclosure of subsidiaries [line items]
Principal operations	IT service and electric control engineering
Ownership (%)	66.99%	66.99%
Region	Indonesia
PT.POSCO ICT INDONESIA [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	66.99%	66.99%
POSCO NCR Coal Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Canada
POSCO NCR Coal Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO WA PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Iron ore sales & mine development
Ownership (%)	100.00%	100.00%
Region	Australia
POSCO WA PTY LTD [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO AMERICA CORP. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	USA
POSCO DAEWOO AMERICA CORP. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO AUSTRALIA GP PTY LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Resource development
Ownership (%)	100.00%	100.00%
Region	Australia
POSCO AUSTRALIA GP PTY LIMITED [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO POWER (PNGPOM) LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Electricity production
Ownership (%)	100.00%	100.00%
Region	Papua New Guinea
POSCO DAEWOO POWER (PNGPOM) LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT. Krakatau Posco Energy [member]
Disclosure of subsidiaries [line items]
Principal operations	Electricity production construction and operation
Ownership (%)	90.00%	90.00%
Region	Indonesia
PT. Krakatau Posco Energy [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	90.00%
POSCO DAEWOO DEUTSCHLAND GMBH [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Germany
POSCO DAEWOO DEUTSCHLAND GMBH [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO JAPAN Corp [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Japan
POSCO DAEWOO JAPAN Corp [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO SINGAPORE PTE LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Singapore
POSCO DAEWOO SINGAPORE PTE LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO ITALIA S.R.L. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Italy
POSCO DAEWOO ITALIA S.R.L. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO CHINA CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	China
POSCO DAEWOO CHINA CO., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Daewoo Textile LLC [member]
Disclosure of subsidiaries [line items]
Principal operations	Textile manufacturing
Ownership (%)	100.00%	100.00%
Region	Uzbekistan
Daewoo Textile LLC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO AUSTRALIA HOLDINGS PTY. LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Resource development
Ownership (%)	100.00%	100.00%
Region	Australia
POSCO DAEWOO AUSTRALIA HOLDINGS PTY. LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO MAURITIUS LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal development and sales
Ownership (%)	100.00%	100.00%
Region	Mauritius
POSCO MAURITIUS LIMITED [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT. KRAKATAU POSCO [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Indonesia
PT. KRAKATAU POSCO [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
POSCO DAEWOO MEXICO S.A. DE C.V. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Mexico
POSCO DAEWOO MEXICO S.A. DE C.V. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Daewoo International Guangzhou Corp. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	China
Daewoo International Guangzhou Corp. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO MALAYSIA SDN BHD [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Malaysia
POSCO DAEWOO MALAYSIA SDN BHD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT.POSCO-Indonesia Inti [member]
Disclosure of subsidiaries [line items]
Principal operations	Mine development
Ownership (%)	99.99%	99.99%
Region	Indonesia
PT.POSCO-Indonesia Inti [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	99.99%	99.99%
POSCO DAEWOO SHANGHAI CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	China
POSCO DAEWOO SHANGHAI CO., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PGSF, L.P. [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in bio tech Industry
Ownership (%)	100.00%	100.00%
Region	USA
PGSF, L.P. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO DAEWOO INDIA PVT., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	India
POSCO DAEWOO INDIA PVT., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO(Dalian) IT Center Development Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development and investment
Ownership (%)	100.00%	100.00%
Region	China
POSCO(Dalian) IT Center Development Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
PT. POSCO E&C INDONESIA [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)	100.00%	100.00%
Region	Indonesia
PT. POSCO E&C INDONESIA [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
HUME COAL PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Raw material manufacturing
Ownership (%)	100.00%	100.00%
Region	Australia
HUME COAL PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Brazil Sao Paulo Steel Processing Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	76.00%	76.00%
Region	Brazil
Brazil Sao Paulo Steel Processing Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	76.00%	76.00%
DAESAN (CAMBODIA) Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development and investment
Ownership (%)	100.00%	100.00%
Region	Cambodia
DAESAN (CAMBODIA) Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction
Ownership (%)	100.00%	100.00%
Region	Brazil
POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POSCO ASSAN TST STEEL INDUSTRY [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Turkey
POSCO ASSAN TST STEEL INDUSTRY [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	60.00%	60.00%
POSCO ASSAN TST STEEL INDUSTRY [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development and investment
Ownership (%)	100.00%	100.00%
Region	Hongkong
HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
POS-LT PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Lithium mining investment
Ownership (%)	100.00%
Region	Australia
POS-LT PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%
POSCO SINGAPORE LNG TRADING PTE. LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	LNG trading
Ownership (%)	100.00%
Region	Singapore
POSCO SINGAPORE LNG TRADING PTE. LTD [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	50.00%
POSCO SINGAPORE LNG TRADING PTE. LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	50.00%
ZHEJIANG POSCO-HUAYOU ESM CO.,LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Anode material manufacturing
Ownership (%)	100.00%
Region	China
ZHEJIANG POSCO-HUAYOU ESM CO.,LTD [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%
POSCO Argentina S.A.U. [member]
Disclosure of subsidiaries [line items]
Principal operations	Mineral exploration/manufacturing/sales
Ownership (%)	100.00%
Region	Argentina
POSCO Argentina S.A.U. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%
POSCO RUS LLC [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading and business development
Ownership (%)		100.00%
Region	Russia
POSCO RUS LLC [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)		90.00%
POSCO RUS LLC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		10.00%
POSCO-CDSFC [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel structure manufacturing
Ownership (%)		100.00%
Region	China
POSCO-CDSFC [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)		50.20%
POSCO-CDSFC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		49.80%
POSCO MESDC S.A. DE C.V. [member]
Disclosure of subsidiaries [line items]
Principal operations	Logistics & Steel sales
Ownership (%)		56.80%
Region	Mexico
POSCO MESDC S.A. DE C.V. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		56.80%
KIS Devonian Canada Corporation [member]
Disclosure of subsidiaries [line items]
Principal operations	Petroleum gas extraction
Ownership (%)		100.00%
Region	Canada
KIS Devonian Canada Corporation [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
POSCO E&C VENEZUELA C.A. [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)		100.00%
Region	Venezuela
POSCO E&C VENEZUELA C.A. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
PT PEN INDONESIA [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction
Ownership (%)		100.00%
Region	Indonesia
PT PEN INDONESIA [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
POSCO Engineering and Construction - UZ [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)		100.00%
Region	Uzbekistan
POSCO Engineering and Construction - UZ [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
Domestic [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Engineering and construction
Ownership (%)	52.80%	52.80%
Region	Pohang
Domestic [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	52.80%	52.80%
Domestic [member] | POSCO Processing & Service [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel sales and trading
Ownership (%)	94.40%	94.40%
Region	Seoul
Domestic [member] | POSCO Processing & Service [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	93.95%	93.95%
Domestic [member] | POSCO Processing & Service [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	0.45%	0.45%
Domestic [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Coated steel manufacturing
Ownership (%)	56.87%	56.87%
Region	Pohang
Domestic [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	56.87%	56.87%
Domestic [member] | POSCO ICT [member]
Disclosure of subsidiaries [line items]
Principal operations	Computer hardware and software distribution
Ownership (%)	65.38%	65.38%
Region	Pohang
Domestic [member] | POSCO ICT [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	65.38%	65.38%
Domestic [member] | POSCO Research Institute [member]
Disclosure of subsidiaries [line items]
Principal operations	Economic research and consulting
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | POSCO Research Institute [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | POSMATE [member]
Disclosure of subsidiaries [line items]
Principal operations	Business facility maintenance
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | POSMATE [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	59.80%	83.83%
Domestic [member] | POSMATE [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	40.20%	16.17%
Domestic [member] | POSCO A&C [member]
Disclosure of subsidiaries [line items]
Principal operations	Architecture and consulting
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | POSCO A&C [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | POSCO Venture Capital Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	95.00%	95.00%
Region	Pohang
Domestic [member] | POSCO Venture Capital Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	95.00%	95.00%
Domestic [member] | eNtoB Corporation [member]
Disclosure of subsidiaries [line items]
Principal operations	Electronic commerce
Ownership (%)	61.13%	61.13%
Region	Seoul
Domestic [member] | eNtoB Corporation [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	7.50%	7.50%
Domestic [member] | eNtoB Corporation [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	53.63%	53.63%
Domestic [member] | POSCO CHEMTECH [member]
Disclosure of subsidiaries [line items]
Principal operations	Refractories manufacturing and sales
Ownership (%)	60.00%	60.00%
Region	Pohang
Domestic [member] | POSCO CHEMTECH [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	60.00%	60.00%
Domestic [member] | POSCO-Terminal Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Transporting and warehousing
Ownership (%)	51.00%	51.00%
Region	Gwangyang
Domestic [member] | POSCO-Terminal Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	51.00%	51.00%
Domestic [member] | POSCO M-TECH [member]
Disclosure of subsidiaries [line items]
Principal operations	Packing materials manufacturing and sales
Ownership (%)	48.85%	48.85%
Region	Pohang
Domestic [member] | POSCO M-TECH [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	48.85%	48.85%
Domestic [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Generation of electricity
Ownership (%)	89.02%	89.02%
Region	Seoul
Domestic [member] | POSCO ENERGY CO., LTD. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	89.02%	89.02%
Domestic [member] | POSCO NIPPON STEEL RHF JOINT VENTURE. CO., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel byproduct manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Pohang
Domestic [member] | POSCO NIPPON STEEL RHF JOINT VENTURE. CO., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
Domestic [member] | MegaAsset Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate rental and sales
Ownership (%)	100.00%	100.00%
Region	Incheon
Domestic [member] | MegaAsset Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Future Creation Fund Postech Early Stage account [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	40.00%	40.00%
Region	Seoul
Domestic [member] | Future Creation Fund Postech Early Stage account [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	40.00%	40.00%
Domestic [member] | POSCO WOMAN'S FUND [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	40.00%	40.00%
Region	Seoul
Domestic [member] | POSCO WOMAN'S FUND [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	40.00%	40.00%
Domestic [member] | SPH Co, ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	House manufacturing and management
Ownership (%)	100.00%	100.00%
Region	Incheon
Domestic [member] | SPH Co, ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Posco Group University [member]
Disclosure of subsidiaries [line items]
Principal operations	Education service and real estate business
Ownership (%)	100.00%	100.00%
Region	Incheon
Domestic [member] | Posco Group University [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | HOTEL LAONZENA [member]
Disclosure of subsidiaries [line items]
Principal operations	Hotel business
Ownership (%)	100.00%	100.00%
Region	Daegu
Domestic [member] | HOTEL LAONZENA [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Growth Ladder POSCO K-Growth Global Fund [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	50.00%	50.00%
Region	Pohang
Domestic [member] | Growth Ladder POSCO K-Growth Global Fund [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	50.00%	50.00%
Domestic [member] | 2015 POSCO New technology II Fund [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	25.00%	25.00%
Region	Pohang
Domestic [member] | 2015 POSCO New technology II Fund [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	25.00%	25.00%
Domestic [member] | Posco e&c Songdo International Building [member]
Disclosure of subsidiaries [line items]
Principal operations	Non-residential building rental
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | Posco e&c Songdo International Building [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | POSCO ES MATERIALS CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Secondary and storage battery manufacturing
Ownership (%)	90.00%	75.32%
Region	Gumi
Domestic [member] | POSCO ES MATERIALS CO., LTD. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	75.32%
Domestic [member] | POSCO Research & Technology [member]
Disclosure of subsidiaries [line items]
Principal operations	Intellectual Property Services and consulting
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | POSCO Research & Technology [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Poscoene [member]
Disclosure of subsidiaries [line items]
Principal operations	Refuse derived fuel and power generation
Ownership (%)	100.00%	100.00%
Region	Seoul
Domestic [member] | Poscoene [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | POSCO Humans [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction
Ownership (%)	90.30%	90.30%
Region	Pohang
Domestic [member] | POSCO Humans [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.30%	90.30%
Domestic [member] | Mapo Hibroad Parking Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction
Ownership (%)	71.00%	71.00%
Region	Seoul
Domestic [member] | Mapo Hibroad Parking Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	71.00%	71.00%
Domestic [member] | BLUE O&M Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Engineering service
Ownership (%)	100.00%	100.00%
Region	Pohang
Domestic [member] | BLUE O&M Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Busan E&E Co,. Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Refuse derived fuel and power generation
Ownership (%)	70.00%	70.00%
Region	Busan
Domestic [member] | Busan E&E Co,. Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
Domestic [member] | POSCO Family Strategy Fund [member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in venture companies
Ownership (%)	100.00%	100.00%
Region	Pohang
Domestic [member] | POSCO Family Strategy Fund [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	69.91%	69.91%
Domestic [member] | POSCO Family Strategy Fund [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	30.09%	30.09%
Domestic [member] | POSCO DAEWOO Corporation [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading, energy & resource development and others
Ownership (%)	62.94%	62.94%
Region	Seoul
Domestic [member] | POSCO DAEWOO Corporation [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	62.90%	62.90%
Domestic [member] | POSCO DAEWOO Corporation [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	0.04%	0.04%
Domestic [member] | Pohang Scrap Recycling Distribution Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel processing and sales
Ownership (%)	51.00%	51.00%
Region	Pohang
Domestic [member] | Pohang Scrap Recycling Distribution Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	51.00%	51.00%
Domestic [member] | PSC Energy Global Co., Ltd. [Member]
Disclosure of subsidiaries [line items]
Principal operations	Investment in energy industry
Ownership (%)	100.00%	100.00%
Region	Pohang
Domestic [member] | PSC Energy Global Co., Ltd. [Member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Suncheon Eco Trans Co., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Train manufacturing and management
Ownership (%)	100.00%	100.00%
Region	Suncheon
Domestic [member] | Suncheon Eco Trans Co., Ltd [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Domestic [member] | Songdo Development PMC (Project Management Company) LLC. [member]
Disclosure of subsidiaries [line items]
Principal operations	Housing business agency
Ownership (%)	100.00%
Region	Incheon
Domestic [member] | Songdo Development PMC (Project Management Company) LLC. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%
Domestic [member] | Pospower Co Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Generation of electricity
Ownership (%)		100.00%
Region	Samcheok
Domestic [member] | Pospower Co Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
Domestic [member] | POCA STEM Co., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Stem cell medicine development
Ownership (%)		100.00%
Region	Seoul
Domestic [member] | POCA STEM Co., Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		100.00%
Domestic [member] | Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 [member]
Disclosure of subsidiaries [line items]
Principal operations	Private equity trust
Ownership (%)		97.47%
Region	Seoul
Domestic [member] | Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)		97.47%
Domestic [member] | Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust [member]
Disclosure of subsidiaries [line items]
Principal operations	Private equity trust
Ownership (%)		99.01%
Region	Seoul
Domestic [member] | Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)		99.01%
Domestic [member] | Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 [member]
Disclosure of subsidiaries [line items]
Principal operations	Private equity trust
Ownership (%)		99.67%
Region	Seoul
Domestic [member] | Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)		99.67%
Foreign [member] | POSCO America Corporation [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel trading
Ownership (%)	100.00%	100.00%
Region	USA
Foreign [member] | POSCO America Corporation [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	99.45%	99.45%
Foreign [member] | POSCO America Corporation [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	0.55%	0.55%
Foreign [member] | POSCO AUSTRALIA PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Raw material sales & mine development
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POSCO AUSTRALIA PTY LTD [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO Canada Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Canada
Foreign [member] | POSCO Canada Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCAN Elkview [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Canada
Foreign [member] | POSCAN Elkview [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO Asia Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel and raw material trading
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO Asia Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-CTPC Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO-CTPC Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	61.91%	56.60%
Foreign [member] | POSCO-CTPC Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	38.09%	43.40%
Foreign [member] | POSCO E&C Vietnam Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel structure manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Vietnam
Foreign [member] | POSCO E&C Vietnam Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | Zhangjiagang Pohang Stainless Steel Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Stainless steel manufacturing and sales
Ownership (%)	82.48%	82.48%
Region	China
Foreign [member] | Zhangjiagang Pohang Stainless Steel Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	58.60%	58.60%
Foreign [member] | Zhangjiagang Pohang Stainless Steel Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	23.88%	23.88%
Foreign [member] | POSCO(Guangdong) Coated Steel Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Plating steel sheet manufacturing and sales
Ownership (%)	97.08%	97.08%
Region	China
Foreign [member] | POSCO(Guangdong) Coated Steel Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	87.04%	87.04%
Foreign [member] | POSCO(Guangdong) Coated Steel Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.04%	10.04%
Foreign [member] | POSCO (Thailand) Company Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Thailand
Foreign [member] | POSCO (Thailand) Company Limited [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	88.58%	88.58%
Foreign [member] | POSCO (Thailand) Company Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	11.42%	11.42%
Foreign [member] | Myanmar POSCO Steel Co., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Zinc relief manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Myanmar
Foreign [member] | Myanmar POSCO Steel Co., Ltd [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
Foreign [member] | POSCO-MKPC SDN BHD [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Malaysia
Foreign [member] | POSCO-MKPC SDN BHD [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	44.69%	44.69%
Foreign [member] | POSCO-MKPC SDN BHD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	25.31%	25.31%
Foreign [member] | Qingdao Pohang Stainless Steel Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Stainless steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | Qingdao Pohang Stainless Steel Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
Foreign [member] | Qingdao Pohang Stainless Steel Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	30.00%	30.00%
Foreign [member] | POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	90.00%
Foreign [member] | POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
Foreign [member] | POSCO-China Qingdao Processing Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO-China Qingdao Processing Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POS-ORE PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Iron ore sales and sales
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POS-ORE PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-China Holding Corp. [member]
Disclosure of subsidiaries [line items]
Principal operations	Holding company
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO-China Holding Corp. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO JAPAN Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel trading
Ownership (%)	100.00%	100.00%
Region	Japan
Foreign [member] | POSCO JAPAN Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POS-CD PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POS-CD PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POS-GC PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POS-GC PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-India Private Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	99.99%	99.99%
Region	India
Foreign [member] | POSCO-India Private Limited [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	99.99%	99.99%
Foreign [member] | POSCO-India Pune Processing Center. Pvt. Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	65.00%	65.00%
Region	India
Foreign [member] | POSCO-India Pune Processing Center. Pvt. Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	65.00%	65.00%
Foreign [member] | POSCO Japan PC CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	86.12%	86.12%
Region	Japan
Foreign [member] | POSCO Japan PC CO., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	86.12%	86.12%
Foreign [member] | POSCO-CFPC Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO-CFPC Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	39.60%	39.60%
Foreign [member] | POSCO-CFPC Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	60.40%	60.40%
Foreign [member] | POSCO E&C CHINA Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO E&C CHINA Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO MPPC S.A. de C.V. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	96.31%	96.31%
Region	Mexico
Foreign [member] | POSCO MPPC S.A. de C.V. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	21.02%	21.02%
Foreign [member] | POSCO MPPC S.A. de C.V. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	75.29%	75.29%
Foreign [member] | Zhangjigang Pohang Port Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Loading and unloading service
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | Zhangjigang Pohang Port Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-VIETNAM Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Vietnam
Foreign [member] | POSCO-VIETNAM Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO MEXICO S.A. DE C.V. [member]
Disclosure of subsidiaries [line items]
Principal operations	Automotive steel sheet manufacturing and sales
Ownership (%)	98.16%	100.00%
Region	Mexico
Foreign [member] | POSCO MEXICO S.A. DE C.V. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	83.28%	84.84%
Foreign [member] | POSCO MEXICO S.A. DE C.V. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	14.88%	15.16%
Foreign [member] | POSCO-Poland Wroclaw Processing Center Sp. z o. o. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	60.00%	60.00%
Region	Poland
Foreign [member] | POSCO-Poland Wroclaw Processing Center Sp. z o. o. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	60.00%	60.00%
Foreign [member] | POS-NP PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Coal sales
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POS-NP PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO DAEWOO WAIGAIQIAO SHANGHAI CO., LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Intermediary trade & bonded warehouse operation
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO DAEWOO WAIGAIQIAO SHANGHAI CO., LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | PT. Bio Inti Agrindo [member]
Disclosure of subsidiaries [line items]
Principal operations	Forest resources development
Ownership (%)	85.00%	85.00%
Region	Indonesia
Foreign [member] | PT. Bio Inti Agrindo [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	85.00%	85.00%
Foreign [member] | POSCO ENGINEERING AND CONSTRUCTION AUSTRALIA (POSCO E&C AUSTRALIA) PTY LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Iron ore development and sales
Ownership (%)	100.00%	100.00%
Region	Australia
Foreign [member] | POSCO ENGINEERING AND CONSTRUCTION AUSTRALIA (POSCO E&C AUSTRALIA) PTY LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-TISCO (JILIN) PROCESSING CENTER Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	60.00%	60.00%
Region	China
Foreign [member] | POSCO-TISCO (JILIN) PROCESSING CENTER Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	50.00%	50.00%
Foreign [member] | POSCO-TISCO (JILIN) PROCESSING CENTER Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
Foreign [member] | POSCO Thainox Public Company Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	STS cold-rolled steel manufacturing and sales
Ownership (%)	84.66%	84.88%
Region	Thailand
Foreign [member] | POSCO Thainox Public Company Limited [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	84.66%	84.88%
Foreign [member] | Hunchun Posco Hyundai Logistics [member]
Disclosure of subsidiaries [line items]
Principal operations	Logistics
Ownership (%)	80.00%	80.00%
Region	China
Foreign [member] | Hunchun Posco Hyundai Logistics [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	80.00%	80.00%
Foreign [member] | POSCO DAEWOO VIETNAM CO., LTD [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Vietnam
Foreign [member] | POSCO DAEWOO VIETNAM CO., LTD [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO(Chongqing) Automotive Processing Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO(Chongqing) Automotive Processing Center Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	90.00%	90.00%
Foreign [member] | POSCO(Chongqing) Automotive Processing Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
Foreign [member] | SUZHOU POSCO-CORE TECHNOLOGY CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Component manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | SUZHOU POSCO-CORE TECHNOLOGY CO., LTD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | PT.Krakatau Posco Chemtech Calcination [member]
Disclosure of subsidiaries [line items]
Principal operations	Quicklime manufacturing and sales
Ownership (%)	80.00%	80.00%
Region	Indonesia
Foreign [member] | PT.Krakatau Posco Chemtech Calcination [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	80.00%	80.00%
Foreign [member] | POSCO AFRICA (PROPRIETARY) LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Mine development
Ownership (%)	100.00%	100.00%
Region	South Africa
Foreign [member] | POSCO AFRICA (PROPRIETARY) LIMITED [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO ICT BRASIL [member]
Disclosure of subsidiaries [line items]
Principal operations	IT service and engineering
Ownership (%)	100.00%	100.00%
Region	Brazil
Foreign [member] | POSCO ICT BRASIL [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | LA-SRDC [member]
Disclosure of subsidiaries [line items]
Principal operations	Scrap manufacturing
Ownership (%)	100.00%	100.00%
Region	USA
Foreign [member] | LA-SRDC [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO Center Beijing [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development, rental and management
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO Center Beijing [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO AMERICA COMERCIALIZADORA S DE RL DE CV [member]
Disclosure of subsidiaries [line items]
Principal operations	Human resource service
Ownership (%)	100.00%	100.00%
Region	Mexico
Foreign [member] | POSCO AMERICA COMERCIALIZADORA S DE RL DE CV [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO(Guangdong) Automotive Steel Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	93.64%	93.64%
Region	China
Foreign [member] | POSCO(Guangdong) Automotive Steel Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	83.64%	83.64%
Foreign [member] | POSCO(Guangdong) Automotive Steel Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
Foreign [member] | POSCO-Malaysia SDN. BHD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	95.42%	95.42%
Region	Malaysia
Foreign [member] | POSCO-Malaysia SDN. BHD. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	81.79%	81.79%
Foreign [member] | POSCO-Malaysia SDN. BHD. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	13.63%	13.63%
Foreign [member] | PT KRAKATAU BLUE WATER [member]
Disclosure of subsidiaries [line items]
Principal operations	Wastewater treatment facilities operation and maintenance
Ownership (%)	67.00%	67.00%
Region	Indonesia
Foreign [member] | PT KRAKATAU BLUE WATER [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	67.00%	67.00%
Foreign [member] | POSCO DAEWOO MYANMAR CORPORATION LIMITED [member]
Disclosure of subsidiaries [line items]
Principal operations	Trading business
Ownership (%)	100.00%	100.00%
Region	Myanmar
Foreign [member] | POSCO DAEWOO MYANMAR CORPORATION LIMITED [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO-Italy Processing Center [member]
Disclosure of subsidiaries [line items]
Principal operations	Stainless steel sheet manufacturing and sales
Ownership (%)	90.00%	90.00%
Region	Italy
Foreign [member] | POSCO-Italy Processing Center [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	80.00%	80.00%
Foreign [member] | POSCO-Italy Processing Center [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	10.00%	10.00%
Foreign [member] | POSCO DAEWOO E&P CANADA CORPORATION [member]
Disclosure of subsidiaries [line items]
Principal operations	Crude oil and natural gas mining
Ownership (%)	100.00%	100.00%
Region	Canada
Foreign [member] | POSCO DAEWOO E&P CANADA CORPORATION [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | Myanmar POSCO C&C Company, Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	70.00%	70.00%
Region	Myanmar
Foreign [member] | Myanmar POSCO C&C Company, Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	70.00%	70.00%
Foreign [member] | POSCO ICT VIETNAM [member]
Disclosure of subsidiaries [line items]
Principal operations	IT service and electric control engineering
Ownership (%)	100.00%	100.00%
Region	Vietnam
Foreign [member] | POSCO ICT VIETNAM [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | Daewoo Global Development. Pte., Ltd [member]
Disclosure of subsidiaries [line items]
Principal operations	Real estate development
Ownership (%)	81.51%	81.51%
Region	Myanmar
Foreign [member] | Daewoo Global Development. Pte., Ltd [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	81.51%	81.51%
Foreign [member] | Myanmar POSCO Engineering & Construction Company, Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Construction and engineering service
Ownership (%)	100.00%	100.00%
Region	Myanmar
Foreign [member] | Myanmar POSCO Engineering & Construction Company, Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POS-Minerals Corporation [member]
Disclosure of subsidiaries [line items]
Principal operations	Mine development management and sales
Ownership (%)	100.00%	100.00%
Region	USA
Foreign [member] | POS-Minerals Corporation [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO(Wuhu) Automotive Processing Center Co., Ltd. [member]
Disclosure of subsidiaries [line items]
Principal operations	Steel manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	China
Foreign [member] | POSCO(Wuhu) Automotive Processing Center Co., Ltd. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	68.57%	68.57%
Foreign [member] | POSCO(Wuhu) Automotive Processing Center Co., Ltd. [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	31.43%	31.43%
Foreign [member] | POSCO Engineering and Construction India Private Limited [member]
Disclosure of subsidiaries [line items]
Principal operations	Civil engineering and construction
Ownership (%)	100.00%	100.00%
Region	India
Foreign [member] | POSCO Engineering and Construction India Private Limited [member] | Subsidiaries [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%
Foreign [member] | POSCO COATED STEEL (THAILAND) CO., LTD. [member]
Disclosure of subsidiaries [line items]
Principal operations	Automotive steel sheet manufacturing and sales
Ownership (%)	100.00%	100.00%
Region	Thailand
Foreign [member] | POSCO COATED STEEL (THAILAND) CO., LTD. [member] | Posco [member]
Disclosure of subsidiaries [line items]
Ownership (%)	100.00%	100.00%

General Information - Details_2

General Information - Details of Non-controlling Interest (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of subsidiaries [line items]
Current assets	₩ 34,151,972	₩ 31,844,259
Non-current assets	44,625,019	47,941,370
Current liabilities	(19,430,577)	(19,490,338)
Non-current liabilities	(12,673,800)	(12,968,566)
Equity	46,672,614	47,326,725	₩ 45,765,269	₩ 45,013,201
Non-controlling interests	3,347,257	3,666,334
Sales	65,154,636	60,186,867	52,939,771
Profit (loss) for the period	1,932,386	2,909,311	1,032,065
Profit (loss) attributable to non-controlling interests	220,484	153,081	(322,742)
Cash flows from operating activities	5,869,725	5,607,310	5,269,418
Cash flows from investing activities	(2,647,970)	(3,817,874)	(3,754,627)
Effect of exchange rate fluctuation on cash held	4,628	(58,997)	12,611
Net increase (decrease) in cash and cash equivalents	31,335	164,911	(2,423,565)
POSCO DAEWOO Corporation [member]
Disclosure of subsidiaries [line items]
Current assets	5,311,596	4,483,544	4,038,313
Non-current assets	4,363,490	4,590,394	4,510,085
Current liabilities	(4,724,056)	(4,221,443)	(3,662,811)
Non-current liabilities	(1,563,107)	(1,549,013)	(1,681,182)
Equity	3,387,923	3,303,482	3,204,405
Non-controlling interests	1,255,728	1,224,303	1,271,750
Sales	23,314,595	20,891,526	15,417,550
Profit (loss) for the period	113,196	115,321	113,832
Profit (loss) attributable to non-controlling interests	41,956	42,739	45,177
Cash flows from operating activities	(61,173)	128,875	337,338
Cash flows from investing activities	(12,780)	(86,365)	(35,054)
Cash flows from financing activities (before dividends to non-controlling interest)	99,496	(19,295)	(295,226)
Dividend to non-controlling interest	(22,862)	(22,597)	(22,597)
Effect of exchange rate fluctuation on cash held	807	(459)	10
Net increase (decrease) in cash and cash equivalents	3,488	159	(15,529)
PT. KRAKATAU POSCO [member]
Disclosure of subsidiaries [line items]
Current assets	615,491	557,041	460,376
Non-current assets	2,730,865	2,771,504	3,304,292
Current liabilities	(1,368,498)	(1,237,255)	(1,120,077)
Non-current liabilities	(1,754,797)	(1,933,247)	(2,337,612)
Equity	223,061	158,043	306,979
Non-controlling interests	66,918	47,413	92,094
Sales	1,871,634	1,635,837	1,244,711
Profit (loss) for the period	54,257	(117,729)	(187,151)
Profit (loss) attributable to non-controlling interests	16,277	(35,318)	(56,145)
Cash flows from operating activities	89,131	(27,817)	45,672
Cash flows from investing activities	(6,432)	(5,502)	(8,804)
Cash flows from financing activities (before dividends to non-controlling interest)	(82,295)	31,782	(36,286)
Effect of exchange rate fluctuation on cash held	21	(147)	67
Net increase (decrease) in cash and cash equivalents	425	(1,684)	649
POSCO CHEMTECH [member]
Disclosure of subsidiaries [line items]
Current assets	416,284	441,325	397,370
Non-current assets	460,905	316,724	243,401
Current liabilities	(140,268)	(145,649)	(109,016)
Non-current liabilities	(10,767)	(970)	(2,337)
Equity	726,154	611,430	529,418
Non-controlling interests	290,461	244,572	211,767
Sales	1,340,984	1,163,918	1,076,455
Profit (loss) for the period	142,918	101,019	41,829
Profit (loss) attributable to non-controlling interests	57,167	40,408	16,732
Cash flows from operating activities	29,865	20,042	30,295
Cash flows from investing activities	(15,801)	(18,699)	(42,021)
Cash flows from financing activities (before dividends to non-controlling interest)		8	(1,250)
Dividend to non-controlling interest	(8,270)	(7,088)	(4,726)
Effect of exchange rate fluctuation on cash held	(17)	(6)	1
Net increase (decrease) in cash and cash equivalents	5,777	(5,743)	(17,701)
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of subsidiaries [line items]
Current assets	4,100,967	4,878,251	5,163,436
Non-current assets	1,911,844	2,444,616	1,710,398
Current liabilities	(3,007,029)	(3,896,680)	(3,284,090)
Non-current liabilities	(608,089)	(833,403)	(855,791)
Equity	2,397,693	2,592,784	2,733,953
Non-controlling interests	1,131,733	1,223,816	1,290,450
Sales	6,799,292	5,794,532	5,352,395
Profit (loss) for the period	290,131	169,011	(760,187)
Profit (loss) attributable to non-controlling interests	136,944	79,775	(358,815)
Cash flows from operating activities	207,729	(84,840)	(211,182)
Cash flows from investing activities	272,230	(171,924)	(102,939)
Cash flows from financing activities (before dividends to non-controlling interest)	(400,499)	150,801	(20,953)
Dividend to non-controlling interest			(14,800)
Effect of exchange rate fluctuation on cash held	1,257	(3,541)	760
Net increase (decrease) in cash and cash equivalents	80,717	(109,504)	(349,114)
POSCO ENERGY CO., LTD. [member]
Disclosure of subsidiaries [line items]
Current assets	825,241	1,054,538	713,039
Non-current assets	2,767,203	2,859,824	3,038,665
Current liabilities	(1,197,845)	(785,462)	(937,668)
Non-current liabilities	(1,445,288)	(2,200,065)	(2,172,226)
Equity	949,311	928,835	641,810
Non-controlling interests	335,203	762,390	514,200
Sales	1,841,187	1,578,026	1,657,890
Profit (loss) for the period	(73,948)	70,795	(130,809)
Profit (loss) attributable to non-controlling interests	(8,116)	7,770	(14,357)
Cash flows from operating activities	16,211	30,295	18,107
Cash flows from investing activities	35,460	(2,792)	(1,047)
Cash flows from financing activities (before dividends to non-controlling interest)	(71,378)	220,317	(2,875)
Dividend to non-controlling interest	(19,813)	(24,183)	(24,378)
Net increase (decrease) in cash and cash equivalents	(39,520)	223,637	(10,193)
Others [member]
Disclosure of subsidiaries [line items]
Current assets	9,137,798	8,579,813	9,696,140
Non-current assets	5,493,324	6,676,559	7,749,277
Current liabilities	(8,026,474)	(8,313,902)	(9,669,053)
Non-current liabilities	(1,925,084)	(2,048,454)	(2,856,498)
Equity	4,679,564	4,894,016	4,919,866
Non-controlling interests	929,506	974,941	945,962
Sales	24,721,939	23,547,072	23,251,563
Profit (loss) for the period	(56,151)	258,053	(461,034)
Profit (loss) attributable to non-controlling interests	(101,156)	39,605	(312,297)
Cash flows from operating activities	14,869	140,418	53,050
Cash flows from investing activities	(13,199)	(63,621)	(253,206)
Cash flows from financing activities (before dividends to non-controlling interest)	(16,094)	(38,090)	204,797
Dividend to non-controlling interest	(6,906)	(12,777)	(7,349)
Effect of exchange rate fluctuation on cash held	1,682	(15,532)	1,687
Net increase (decrease) in cash and cash equivalents	(19,648)	10,398	(1,021)
Non-controlling Interest [member]
Disclosure of subsidiaries [line items]
Current assets	20,407,377	19,994,512	20,468,674
Non-current assets	17,727,631	19,659,621	20,556,118
Current liabilities	(18,464,170)	(18,600,391)	(18,782,715)
Non-current liabilities	(7,307,132)	(8,565,152)	(9,905,646)
Equity	12,363,706	12,488,590	12,336,431
Non-controlling interests	4,009,549	4,477,435	4,326,223
Sales	59,889,631	54,610,911	48,000,564
Profit (loss) for the period	470,403	596,470	(1,383,520)
Profit (loss) attributable to non-controlling interests	143,072	174,979	(679,705)
Cash flows from operating activities	296,632	206,973	273,280
Cash flows from investing activities	259,478	(348,903)	(443,071)
Cash flows from financing activities (before dividends to non-controlling interest)	(470,770)	345,523	(151,793)
Dividend to non-controlling interest	(57,851)	(66,645)	(73,850)
Effect of exchange rate fluctuation on cash held	3,750	(19,685)	2,525
Net increase (decrease) in cash and cash equivalents	₩ 31,239	₩ 117,263	₩ (392,909)

General Information - Details_3

General Information - Details of Associates (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Domestic [member] | New Songdo International City Development, LLC [member]
Disclosure of associates [line items]
Category of business	Real estate rental
Ownership (%)	29.90%	29.90%
Region	Seoul
Domestic [member] | Gale International Korea, LLC [member]
Disclosure of associates [line items]
Category of business	Real estate rental
Ownership (%)	29.90%	29.90%
Region	Seoul
Domestic [member] | SNNC [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	49.00%	49.00%
Region	Gwangyang
Domestic [member] | KONES, Corp. [member]
Disclosure of associates [line items]
Category of business	Technical service
Ownership (%)	41.67%	41.67%
Region	Gyeongju
Domestic [member] | Chungju Enterprise City Development Co.,Ltd [member]
Disclosure of associates [line items]
Category of business	Real estate development
Ownership (%)	29.53%	29.53%
Region	Chungju
Domestic [member] | DAEHO GLOBAL MANAGEMENT CO., LTD. [member]
Disclosure of associates [line items]
Category of business	Investment advisory service
Ownership (%)	35.82%	35.82%
Region	Pohang
Domestic [member] | Mokpo Deayang Industrial Corporation [member]
Disclosure of associates [line items]
Category of business	Real estate development and rental
Ownership (%)	27.40%	27.40%
Region	Mokpo
Domestic [member] | Gunggi Green Energy [member]
Disclosure of associates [line items]
Category of business	Electricity generation
Ownership (%)	19.00%	19.00%
Region	Hwaseong
Domestic [member] | Pohang Special Welding Co.,Ltd. [member]
Disclosure of associates [line items]
Category of business	Welding material and tools manufacturing and sales
Ownership (%)	50.00%	50.00%
Region	Pohang
Domestic [member] | KoFC POSCO HANWHA KB Shared Growth No. 2. Private Equity Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	12.50%	12.50%
Region	Seoul
Domestic [member] | EQP POSCO Global No1 Natural Resources Private Equity Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	31.27%	31.14%
Region	Seoul
Domestic [member] | KC Chemicals CORP [member]
Disclosure of associates [line items]
Category of business	Machinery manufacturing
Ownership (%)	19.00%	19.00%
Region	Hwaseong
Domestic [member] | Garolim Tidal Power Plant Co.,Ltd [member]
Disclosure of associates [line items]
Category of business	Tidal power plant construction and management
Ownership (%)	32.13%	32.13%
Region	Seosan
Domestic [member] | POSTECH Social Enterprise Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	9.17%	9.17%
Region	Seoul
Domestic [member] | QSONE Co.,Ltd. [member]
Disclosure of associates [line items]
Category of business	Real estate rental and facility management
Ownership (%)	50.00%	50.00%
Region	Seoul
Domestic [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Electricity generation
Ownership (%)	45.67%	45.67%
Region	Chuncheon
Domestic [member] | Keystone NO. 1. Private Equity Fund [member]
Disclosure of associates [line items]
Category of business	Private equity financial
Ownership (%)	40.45%	40.45%
Region	Seoul
Domestic [member] | Noeul Green Energy [member]
Disclosure of associates [line items]
Category of business	Electricity generation
Ownership (%)	10.00%	10.00%
Region	Seoul
Domestic [member] | Posco-IDV Growth Ladder IP Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	17.86%	17.86%
Region	Seoul
Domestic [member] | Daesung Steel [member]
Disclosure of associates [line items]
Category of business	Steel sales
Ownership (%)	17.54%	17.54%
Region	Busan
Domestic [member] | Pohang E&E Co,. Ltd. [member]
Disclosure of associates [line items]
Category of business	Investment in waste energy
Ownership (%)	30.00%	30.00%
Region	Pohang
Domestic [member] | POSCO Energy Valley Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	20.00%	20.00%
Region	Pohang
Domestic [member] | 2016 PoscoPlutus New Technology Investment Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	25.17%	25.17%
Region	Seoul
Domestic [member] | Hyundai Invest Guggenheim CLO Private Special Asset Investment Trust II [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	38.47%	38.47%
Region	Seoul
Domestic [member] | PoscoPlutus Bio Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	11.97%	11.97%
Region	Seoul
Domestic [member] | PoscoPlutus Project Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	11.91%	11.91%
Region	Seoul
Domestic [member] | Posco Agri-Food Export Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	30.00%	30.00%
Region	Seoul
Domestic [member] | PoscoPlutus Project Second Project Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	0.61%	0.61%
Region	Seoul
Domestic [member] | Posco Culture Contents Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	31.67%	31.67%
Region	Seoul
Domestic [member] | PCC Centroid New 1st Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	24.10%	24.10%
Region	Seoul
Domestic [member] | PCC Amberstone Private Equity Fund I [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	8.80%	9.71%
Region	Seoul
Domestic [member] | UITrans LRT Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Transporting
Ownership (%)	38.19%	38.19%
Region	Seoul
Domestic [member] | POSCO Advanced Technical Staff Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	15.87%	15.87%
Region	Seoul
Domestic [member] | POSCO 4th Industrial Revolution Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	19.05%	20.00%
Region	Seoul
Domestic [member] | Clean Gimpo Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	29.58%	29.58%
Region	Gimpo
Domestic [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	18.26%	18.26%
Region	Anyang
Domestic [member] | Pureun Tongyeong Enviro Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Sewerage treatment
Ownership (%)	20.40%	20.40%
Region	Tongyeong
Domestic [member] | Pure Gimpo Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	28.79%	28.79%
Region	Seoul
Domestic [member] | POSCO PLANTEC Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Construction of industrial plant
Ownership (%)	73.94%	73.94%
Region	Ulsan
Domestic [member] | Postech Early Stage Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	10.00%	10.00%
Region	Pohang
Domestic [member] | Posgreen Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Lime and plaster manufacturing
Ownership (%)	19.00%	19.00%
Region	Gwangyang
Domestic [member] | Clean Iksan Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	23.50%	23.50%
Region	Iksan
Domestic [member] | Innovalley Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Real estate development
Ownership (%)	28.77%	28.77%
Region	Yongin
Domestic [member] | Applied Science Corp. [member]
Disclosure of associates [line items]
Category of business	Machinery manufacturing
Ownership (%)	22.89%	23.87%
Region	Paju
Domestic [member] | Pohang Techno Valley PFV Corporation [member]
Disclosure of associates [line items]
Category of business	Real estate development, supply and rental
Ownership (%)	57.39%	57.39%
Region	Pohang
Domestic [member] | Blue Ocean private equity fund [member]
Disclosure of associates [line items]
Category of business	Private equity financial
Ownership (%)	27.52%	27.52%
Region	Seoul
Domestic [member] | Western Inland Highway Co Ltd [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	27.50%
Region	Incheon
Domestic [member] | Metropolitan Outer Ring Expressway Co Ltd [member]
Disclosure of associates [line items]
Category of business	Investment in Expressway
Ownership (%)	47.58%
Region	Incheon
Domestic [member] | IT Engineering CO. Ltd [member]
Disclosure of associates [line items]
Category of business	Vehicle engineering
Ownership (%)	10.84%
Region	Seoul
Domestic [member] | PCC Bio 1ST Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	13.46%
Region	Seoul
Domestic [member] | INNOPOLIS Job Creation Fund II [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	6.43%
Region	Seoul
Domestic [member] | Pospower Co Ltd [member]
Disclosure of associates [line items]
Category of business	Generation of electricity
Ownership (%)	34.00%
Region	Samcheok
Domestic [member] | INKOTECH INC [Member]
Disclosure of associates [line items]
Category of business	Electricity generation and sales
Ownership (%)	10.00%
Region	Seoul
Domestic [member] | PCC Social Enterprise Fund II [member]
Disclosure of associates [line items]
Category of business	Investment in venture companies
Ownership (%)	16.67%
Region	Seoul
Domestic [member] | PCC Amberstone Private Equity Fund II [member]
Disclosure of associates [line items]
Category of business	Private equity trust
Ownership (%)	19.70%
Region	Seoul
Domestic [member] | Synapse Fund [member]
Disclosure of associates [line items]
Category of business	Investment in new technologies
Ownership (%)	16.26%
Region	Seoul
Domestic [member] | NEXTRAIN Co Ltd [member]
Disclosure of associates [line items]
Category of business	Service maintenance and management
Ownership (%)	32.00%
Region	Incheon
Domestic [member] | TK CHEMICAL CORPORATION [member]
Disclosure of associates [line items]
Category of business	Chemical
Ownership (%)	8.80%
Region	Daegu
Domestic [member] | Hanil-Daewoo Cement Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Cement
Ownership (%)	15.00%
Region	Incheon
Domestic [member] | Pohang Techno Valley AMC [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)		29.50%
Region	Pohang
Foreign [member] | VSC POSCO Steel Corporation [member]
Disclosure of associates [line items]
Category of business	Steel processing and sales
Ownership (%)	50.00%	50.00%
Region	Vietnam
Foreign [member] | POSCHROME (PROPRIETARY) LIMITED [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	50.00%	50.00%
Region	South Africa
Foreign [member] | CAML RESOURCES PTY LTD. [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	33.34%	33.34%
Region	Australia
Foreign [member] | Nickel mining company SAS [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	49.00%	49.00%
Region	New Caledonia
Foreign [member] | PT. wampu electric power [member]
Disclosure of associates [line items]
Category of business	Construction and civil engineering
Ownership (%)	20.00%	20.00%
Region	Indonesia
Foreign [member] | POSK(Pinghu) Steel Processing Center Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Steel processing and sales
Ownership (%)	20.00%	20.00%
Region	China
Foreign [member] | PT.INDONESIA POS CHEMTECH CHOSUN Ref [member]
Disclosure of associates [line items]
Category of business	Refractory manufacturing and sales
Ownership (%)	30.19%	30.19%
Region	Indonesia
Foreign [member] | NS-Thainox Auto Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Steel manufacturing and sales
Ownership (%)	49.00%	49.00%
Region	Vietnam
Foreign [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of associates [line items]
Category of business	Tinplate manufacturing and sales
Ownership (%)	34.00%	34.00%
Region	China
Foreign [member] | PT. Tanggamus Electric Power [member]
Disclosure of associates [line items]
Category of business	Construction and civil engineering
Ownership (%)	17.50%	17.50%
Region	Indonesia
Foreign [member] | LLP POSUK Titanium [member]
Disclosure of associates [line items]
Category of business	Titanium manufacturing and sales
Ownership (%)	36.83%	36.83%
Region	Kazakhstan
Foreign [member] | LI3 ENERGY INC [member]
Disclosure of associates [line items]
Category of business	Resource development
Ownership (%)	26.06%	26.06%
Region	Peru
Foreign [member] | IMFA ALLOYS FINLEASE LTD. [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	24.00%	24.00%
Region	India
Foreign [member] | KRAKATAU POS-CHEM DONG-SUH CHEMICAL [member]
Disclosure of associates [line items]
Category of business	Chemical by-product manufacturing and sales
Ownership (%)	19.00%	19.00%
Region	Indonesia
Foreign [member] | 7623704 Canada Inc. [member]
Disclosure of associates [line items]
Category of business	Investments management
Ownership (%)	10.40%	10.40%
Region	Canada
Foreign [member] | Hamparan Mulya [member]
Disclosure of associates [line items]
Category of business	Resource development
Ownership (%)	45.00%	45.00%
Region	Indonesia
Foreign [member] | POS-SEAH STEEL WIRE (TIANJIN) CO., Ltd [member]
Disclosure of associates [line items]
Category of business	Steel manufacturing and sales
Ownership (%)	25.00%	25.00%
Region	China
Foreign [member] | Eureka Moly LLC [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	20.00%	20.00%
Region	USA
Foreign [member] | PT. batutua tembaga raya [member]
Disclosure of associates [line items]
Category of business	Raw material manufacturing and sales
Ownership (%)	22.00%	22.00%
Region	Indonesia
Foreign [member] | KIRIN VIETNAM CO., LTD [member]
Disclosure of associates [line items]
Category of business	Panel manufacturing
Ownership (%)	19.00%	19.00%
Region	Vietnam
Foreign [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Steel processing and sales
Ownership (%)	25.00%	25.00%
Region	China
Foreign [member] | POS-SeAH Steel Wire (Thailand) Co., Ltd. [member]
Disclosure of associates [line items]
Category of business	Steel manufacturing and sales
Ownership (%)	25.00%	25.00%
Region	Thailand
Foreign [member] | Jupiter Mines Limited [member]
Disclosure of associates [line items]
Category of business	Resource development
Ownership (%)	6.93%	17.06%
Region	Australia
Foreign [member] | SAMHWAN VINA CO., LTD [member]
Disclosure of associates [line items]
Category of business	Steel manufacturing and sales
Ownership (%)	19.00%	19.00%
Region	Vietnam
Foreign [member] | JB CLARK HILLS [member]
Disclosure of associates [line items]
Category of business	Construction
Ownership (%)	25.00%	25.00%
Region	Philippines
Foreign [member] | Saudi-Korean Company for Maintenance Properties Management LLC [member]
Disclosure of associates [line items]
Category of business	Building management
Ownership (%)	19.00%	19.00%
Region	Saudi Arabia
Foreign [member] | Sebang Steel [member]
Disclosure of associates [line items]
Category of business	Scrap sales
Ownership (%)	49.00%	49.00%
Region	Japan
Foreign [member] | NCR LLC [member]
Disclosure of associates [line items]
Category of business	Coal sales
Ownership (%)	29.41%	29.41%
Region	Canada
Foreign [member] | AMCI (WA) PTY LTD [member]
Disclosure of associates [line items]
Category of business	Iron ore sales & mine development
Ownership (%)	49.00%	49.00%
Region	Australia
Foreign [member] | SHANGHAI LANSHENG DAEWOO CORP. [member]
Disclosure of associates [line items]
Category of business	Trading
Ownership (%)	49.00%	49.00%
Region	China
Foreign [member] | SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN'L TRADING CO., LTD. [member]
Disclosure of associates [line items]
Category of business	Trading
Ownership (%)	49.00%	49.00%
Region	China
Foreign [member] | General Medicines Company Ltd. [member]
Disclosure of associates [line items]
Category of business	Medicine manufacturing and sales
Ownership (%)	33.00%	33.00%
Region	Sudan
Foreign [member] | Korea LNG Ltd. [member]
Disclosure of associates [line items]
Category of business	Gas production and sales
Ownership (%)	20.00%	20.00%
Region	England
Foreign [member] | AES-VCM Mong Duong Power Company Limited [member]
Disclosure of associates [line items]
Category of business	Electricity generation
Ownership (%)	30.00%	30.00%
Region	Vietnam
Foreign [member] | KG Power(M) SDN. BHD [member]
Disclosure of associates [line items]
Category of business	Resource development
Ownership (%)	20.00%	20.00%
Region	Malaysia
Foreign [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of associates [line items]
Category of business	Pipeline construction and management
Ownership (%)	25.04%	25.04%
Region	Myanmar
Foreign [member] | GLOBAL KOMSCO Daewoo LLC [member]
Disclosure of associates [line items]
Category of business	Cotton celluloid manufacturing and sales
Ownership (%)	35.00%	35.00%
Region	Uzbekistan
Foreign [member] | POSCO-Poggenamp Electrical Steel Pvt. Ltd. [member]
Disclosure of associates [line items]
Category of business	Steel processing and sales
Ownership (%)	26.00%	26.00%
Region	India
Foreign [member] | Qingdao Pohang DGENX Stainless Steel Pipe Co Ltd [member]
Disclosure of associates [line items]
Category of business	Exhaust meter manufacturing
Ownership (%)	40.00%
Region	China
Foreign [member] | SHINPOONG DAEWOO PHARMA VIETNAM CO.,LTD [member]
Disclosure of associates [line items]
Category of business	Medicine production
Ownership (%)	3.42%
Region	Vietnam
Foreign [member] | ERAE Automotive Systems Mexico, S. DE R.L. DE C.V [member]
Disclosure of associates [line items]
Category of business	Automobile parts manufacturing
Ownership (%)	7.65%
Region	Mexico

General Information - Details_4

General Information - Details of Joint Ventures (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Domestic [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of joint ventures [line items]
Category of business	Steel processing and sales
Ownership (%)	60.00%	60.00%
Region	Gwangyang
Domestic [member] | POSCO-SGI Falcon Pharma Biological Secondary Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	24.55%	24.55%
Region	Seoul
Domestic [member] | KOBRASCO [member]
Disclosure of joint ventures [line items]
Ownership (%)		50.00%
Domestic [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of joint ventures [line items]
Ownership (%)		20.00%
Domestic [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of joint ventures [line items]
Ownership (%)		25.00%
Domestic [member] | DMSA/AMSA [member]
Disclosure of joint ventures [line items]
Ownership (%)		4.00%
Domestic [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of joint ventures [line items]
Ownership (%)		12.50%
Domestic [member] | POSCO-NPS Niobium LLC [member]
Disclosure of joint ventures [line items]
Ownership (%)		50.00%
Foreign [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of joint ventures [line items]
Ownership (%)		60.00%
Foreign [member] | POSCO-KB Shipbuilding Restructuring Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	18.75%	18.75%
Region	Seoul
Foreign [member] | POSCO-NSC Venture Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	16.67%	16.67%
Region	Seoul
Foreign [member] | Posto Plutus Project 3rd Project Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	5.96%	5.96%
Region	Seoul
Foreign [member] | PCC Bio 2nd Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	19.72%
Region	Seoul
Foreign [member] | PCC Material 3rd Fund [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)	2.38%
Region	Seoul
Foreign [member] | PCC L&K IST FUND [member]
Disclosure of joint ventures [line items]
Category of business	Investment in new technologies
Ownership (%)		10.00%
Region	Seoul
Foreign [member] | KOBRASCO [member]
Disclosure of joint ventures [line items]
Category of business	Steel materials manufacturing and sales
Ownership (%)	50.00%	50.00%
Region	Brazil
Foreign [member] | USS-POSCO Industries [member]
Disclosure of joint ventures [line items]
Category of business	Cold-rolled steel manufacturing and sales
Ownership (%)	50.00%	50.00%
Region	USA
Foreign [member] | PT. POSMI Steel Indonesia [member]
Disclosure of joint ventures [line items]
Category of business	Steel processing and sales
Ownership (%)	36.69%	36.69%
Region	Indonesia
Foreign [member] | United Spiral Pipe, LLC [member]
Disclosure of joint ventures [line items]
Category of business	Material manufacturing and sales
Ownership (%)	35.00%	35.00%
Region	USA
Foreign [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of joint ventures [line items]
Category of business	Steel manufacturing and sales
Ownership (%)	20.00%	20.00%
Region	Brazil
Foreign [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of joint ventures [line items]
Category of business	Steel processing and sales
Ownership (%)	25.00%	25.00%
Region	China
Foreign [member] | POSCO-SAMSUNG-Slovakia Processing Center [member]
Disclosure of joint ventures [line items]
Category of business	Steel processing and sales
Ownership (%)	30.00%	30.00%
Region	Slovakia
Foreign [member] | VNS-DAEWOO Co., Ltd. [member]
Disclosure of joint ventures [line items]
Category of business	Steel scrap processing and sales
Ownership (%)	50.00%	40.00%
Region	Vietnam
Foreign [member] | YULCHON MEXICO S.A. DE C.V. [member]
Disclosure of joint ventures [line items]
Category of business	Tube for automobile manufacturing
Ownership (%)	19.00%	19.00%
Region	Mexico
Foreign [member] | Hyunson Engineering & Construction HYENCO [member]
Disclosure of joint ventures [line items]
Category of business	Construction
Ownership (%)	4.89%	4.90%
Region	Algeria
Foreign [member] | POSCO E&C Saudi Arabia [member]
Disclosure of joint ventures [line items]
Category of business	Civil engineering and construction
Ownership (%)	40.00%	40.00%
Region	Saudi Arabia
Foreign [member] | POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member]
Disclosure of joint ventures [line items]
Category of business	Automotive parts manufacturing
Ownership (%)	19.90%	19.90%
Region	China
Foreign [member] | POS INFRA AUTO [member]
Disclosure of joint ventures [line items]
Category of business	Automotive parts manufacturing
Ownership (%)	16.20%	16.20%
Region	China
Foreign [member] | POSCO(Yantai)Automotive Processing Center Co., Ltd. [member]
Disclosure of joint ventures [line items]
Category of business	Automotive parts manufacturing
Ownership (%)	11.10%	11.10%
Region	China
Foreign [member] | POS-AUSTEM WUHAN AUTOMOTIVE CO.,LTD [member]
Disclosure of joint ventures [line items]
Category of business	Automotive parts manufacturing
Ownership (%)	13.00%	13.00%
Region	China
Foreign [member] | Kwanika Copper Corporation [member]
Disclosure of joint ventures [line items]
Category of business	Energy & resource development
Ownership (%)	35.00%	35.00%
Region	Canada
Foreign [member] | DMSA/AMSA [member]
Disclosure of joint ventures [line items]
Category of business	Energy & resource development
Ownership (%)	4.00%	4.00%
Region	Madagascar
Foreign [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of joint ventures [line items]
Category of business	Energy & resource development
Ownership (%)	12.50%	12.50%
Region	Australia
Foreign [member] | POSCO-NPS Niobium LLC [member]
Disclosure of joint ventures [line items]
Category of business	Mine development
Ownership (%)	50.00%	50.00%
Region	USA
Foreign [member] | Korea Siberia Wood CJSC [member]
Disclosure of joint ventures [line items]
Category of business	Forest resource development
Ownership (%)		50.00%
Region	Russia

General Information - Consolida

General Information - Consolidated Subsidiaries Acquired or Newly Established (Detail)	12 Months Ended
	Dec. 31, 2018
POS-LT PTY LTD [member]
Disclosure of subsidiaries [line items]
Date of addition	2018-03
Ownership (%)	100.00%
Reason	New establishment
POSCO SINGAPORE LNG TRADING PTE. LTD [member]
Disclosure of subsidiaries [line items]
Date of addition	2018-06
Ownership (%)	100.00%
Reason	New establishment
ZHEJIANG POSCO-HUAYOU ESM CO.,LTD [member]
Disclosure of subsidiaries [line items]
Date of addition	2018-06
Ownership (%)	100.00%
Reason	New establishment
POSCO Argentina S.A.U. [member]
Disclosure of subsidiaries [line items]
Date of addition	2018-10
Ownership (%)	100.00%
Reason	New establishment
Songdo Development PMC (Project Management Company) LLC. [member]
Disclosure of subsidiaries [line items]
Date of addition	2018-10
Ownership (%)	100.00%
Reason	New establishment

General Information - Subsidiar

General Information - Subsidiaries That Were Excluded From Consolidation (Detail)	12 Months Ended
	Dec. 31, 2018
KIS Devonian Canada Corporation [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-02
Reason	Merged into POSCO DAEWOO E&P CANADA CORPORATION
POSCO-CDSFC [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-02
Reason	Merged into POSCO China Dalian Plate Processing Center Co., Ltd.
POCA STEM Co., Ltd [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-03
Reason	Liquidation
POSCO E&C VENEZUELA C.A. [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-03
Reason	Liquidation
PT PEN INDONESIA [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-03
Reason	Merged into PT. POSCO E&C INDONESIA
Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-2 [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-04
Reason	Disposal
Mirae Asset Smart Q Sigma 2.0 Professional Private Equity Trust [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-05
Reason	Disposal
Kyobo Securities Bond Plus 6M Professional Private Equity Trust W-5 [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-05
Reason	Disposal
POSCO RUS LLC [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-05
Reason	Liquidation
Pospower Co Ltd [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-07
Reason	Reclassification to an associate upon loss of control due to a decline in ownership
POSCO MESDC S.A. DE C.V. [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-08
Reason	Merged into POSCO MEXICO S.A. DE C.V.
POSCO Engineering and Construction - UZ [member]
Disclosure of subsidiaries [line items]
Date of exclusion	2018-11
Reason	Liquidation

Statement of Compliance - Summa

Statement of Compliance - Summary of Impact on Net of Tax on Transition to New Update on Retained Earnings and Non-controlling Interests (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)
Retained earnings [member]
Disclosure of initial application of standards or interpretations [line items]
Shipping services included in the sales contract	₩ (949)
Separate construction contract determined to be a single performance obligation	452
Variable consideration for sales discounts and price adjustments based on performance	(2,613)
Change in revenue recognition method for contracts without enforceable right to payment	(1,189)
Change in percentage of completion due to excessive use of materials	(2,855)
Recognize prepaid contract cost as an expense	(63,753)
Total	(70,907)
Non-controlling interests [member]
Disclosure of initial application of standards or interpretations [line items]
Shipping services included in the sales contract	(156)
Separate construction contract determined to be a single performance obligation	628
Variable consideration for sales discounts and price adjustments based on performance	172
Change in revenue recognition method for contracts without enforceable right to payment	(1,115)
Change in percentage of completion due to excessive use of materials	(1,512)
Recognize prepaid contract cost as an expense	(56,993)
Total	₩ (58,976)

Statement of Compliance - Sum_2

Statement of Compliance - Summary of Effects of Adoption of IFRS No. 15 to Company's Consolidated Statements of Financial Position and Consolidated Statements of Comprehensive Income (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated financial statements of financial position
Current assets	₩ 34,151,972	₩ 31,844,259
Trade accounts and notes receivable	9,130,204	8,824,563
Inventories	12,153,303	10,793,781
Other current assets	684,464	821,242
Non-current assets	44,625,019	47,941,370
Deferred tax assets	1,408,787	1,463,055
Current liabilities	19,430,577	19,490,338
Others payables	1,720,097	1,753,461
Current income tax liabilities	948,166	515,538
Provisions	298,453	110,946
Other current liabilities	2,090,307	2,240,919
Retained earnings	44,160,659	42,974,658
Non-controllinginterests	3,347,257	3,666,334
Consolidated statements of comprehensive income
Revenue	65,154,636	60,186,867	₩ 52,939,771
Cost of sales	(57,129,060)	(51,915,597)	(46,271,465)
Finance costs	(2,244,416)	(2,484,277)	(3,014,190)
Profit before income taxes	3,616,016	4,095,051	1,411,609
Income tax expense	1,683,630	1,185,740	379,544
Profit	1,932,386	₩ 2,909,311	₩ 1,032,065
Restated balance [member]
Consolidated financial statements of financial position
Current assets	34,151,972
Trade accounts and notes receivable	9,130,204
Inventories	12,153,303
Other current assets	684,464
Non-current assets	44,625,019
Deferred tax assets	1,408,787
Current liabilities	19,430,577
Others payables	1,720,097
Current income tax liabilities	948,166
Provisions	298,453
Other current liabilities	2,090,307
Retained earnings	44,160,659
Non-controllinginterests	3,347,257
Consolidated statements of comprehensive income
Revenue	65,154,636
Cost of sales	(57,129,060)
Selling and administrative expenses	(2,429,781)
Finance costs	(2,244,416)
Profit before income taxes	3,616,016
Income tax expense	(1,683,630)
Profit	1,932,386
Increase (decrease) due to changes in accounting policy required by IFRS15 [member]
Consolidated financial statements of financial position
Current assets	193,400
Trade accounts and notes receivable	86,293
Inventories	6,584
Other current assets	100,523
Non-current assets	(41,589)
Deferred tax assets	(41,589)
Current liabilities	21,605
Others payables	17,809
Current income tax liabilities	(640)
Provisions	(28,748)
Other current liabilities	33,184
Retained earnings	68,182
Non-controllinginterests	62,024
Consolidated statements of comprehensive income
Revenue	135
Cost of sales	1,206,973
Selling and administrative expenses	(1,204,764)
Finance costs	178
Profit before income taxes	2,522
Income tax expense	(2,198)
Profit	324
Previously stated [member]
Consolidated financial statements of financial position
Current assets	34,345,372
Trade accounts and notes receivable	9,216,497
Inventories	12,159,887
Other current assets	784,987
Non-current assets	44,583,430
Deferred tax assets	1,367,198
Current liabilities	19,452,182
Others payables	1,737,906
Current income tax liabilities	947,526
Provisions	269,705
Other current liabilities	2,123,491
Retained earnings	44,228,841
Non-controllinginterests	3,409,281
Consolidated statements of comprehensive income
Revenue	65,154,771
Cost of sales	(55,922,087)
Selling and administrative expenses	(3,634,545)
Finance costs	(2,244,238)
Profit before income taxes	3,618,538
Income tax expense	(1,685,828)
Profit	₩ 1,932,710

Statement of Compliance - Sum_3

Statement of Compliance - Summary of Impact, Net of Tax, of Transition to IFRS No. 9 on Reserves, Retained Earnings and Non-Controlling Interests (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves	₩ (1,404,368)		₩ (682,556)
Retained earnings	44,160,659		42,974,658
Noncontrolling interests	₩ 3,347,257		₩ 3,666,334
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves		₩ (498,517)
Retained earnings		447,067
Noncontrolling interests		(34,754)
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member] | Classification to fair value through profit or loss in securities and select to fair value through other comprehensive income in equity securities [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves		(498,517)
Retained earnings		498,517
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member] | Expected credit losses [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Retained earnings		(51,450)
Noncontrolling interests		₩ (34,754)

Statement of Compliance - Sum_4

Statement of Compliance - Summary of Impact, Net of Tax, of Transition to IFRS No. 9 on Reserves, Retained Earnings and Non-Controlling Interests (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves	₩ (1,404,368)		₩ (682,556)
Retained earnings	₩ 44,160,659		₩ 42,974,658
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves		₩ (498,517)
Retained earnings		447,067
Fair value through other comprehensive income [Member] | Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Reserves		(76,992)
Retained earnings		₩ 76,992

Statement of Compliance - Sum_5

Statement of Compliance - Summary of Initial Application, Measurement Categories and Carrying Amounts of Financial Assets in Accordance with IAS No. 39 and IFRS No. 9 (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Disclosure of detailed information about financial instruments [line items]
Cash and cash equivalents	₩ 2,643,865		₩ 2,612,530
Trade accounts and notes receivable	9,130,204		8,824,563
Other receivables	1,385,629		1,636,006
Equity securities	(1,238,630)
Other Securities	338,106
Short-term financial instruments	₩ 6,099,303		5,545,667
IFRS9 [member] | Financial assets at fair value through profit or loss [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		₩ 65,051
Other receivables		1,898
Equity securities		17,812
Debt securities		188,276
Other Securities		366,241
Short-term financial instruments		5,547,637
IFRS9 [member] | Hedging instrument category [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		3,239
IFRS9 [member] | Amortized cost [Member]
Disclosure of detailed information about financial instruments [line items]
Cash and cash equivalents		2,612,530
Trade accounts and notes receivable		8,799,161
Other receivables		2,188,820
Debt securities		5,211
Deposit instruments		1,358,311
IFRS9 [member] | Fair value through other comprehensive income [Member]
Disclosure of detailed information about financial instruments [line items]
Equity securities		1,403,483
Debt securities		₩ 2,303
IAS 39 [member] | Financial assets at fair value through profit or loss [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets			65,051
Short-term financial instruments			1,970
IAS 39 [member] | Hedging instrument category [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets			3,239
IAS 39 [member] | Loans and receivables [member]
Disclosure of detailed information about financial instruments [line items]
Cash and cash equivalents			2,612,530
Trade accounts and notes receivable			8,901,867
Other receivables			2,195,466
Deposit instruments			1,358,311
Short-term financial instruments			5,545,667
IAS 39 [member] | Available-for-sale financial assets [member]
Disclosure of detailed information about financial instruments [line items]
Equity securities			1,421,295
Debt securities			190,579
Other Securities			366,241
IAS 39 [member] | Held-to-maturity financial assets [member]
Disclosure of detailed information about financial instruments [line items]
Debt securities			₩ 5,211

Statement of Compliance - Sum_6

Statement of Compliance - Summary of Initial Application, Measurement Categories and Carrying Amounts of Financial Assets in Accordance with IAS No. 39 and IFRS No. 9 (Parenthetical) (Detail) - KRW (₩)	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of detailed information about financial instruments [line items]
Loss allowance	₩ 916,790,000,000		₩ 1,094,464,000,000	₩ 977,771,000,000	₩ 999,678,000,000
Reserves	(1,404,368,000,000)		(682,556,000,000)
Retained earnings	44,160,659,000,000		42,974,658,000,000
Non-controlling interests	₩ 3,347,257,000,000		₩ 3,666,334,000,000
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of detailed information about financial instruments [line items]
Reserves		₩ (498,517,000,000)
Retained earnings		447,067,000,000
Non-controlling interests		(34,754,000,000)
Financial assets at fair value through profit or loss [member] | Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of detailed information about financial instruments [line items]
Reserves		(421,525)
Retained earnings		421,525
Loans and receivables [member] | Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of detailed information about financial instruments [line items]
Loss allowance		107,454,000,000
Retained earnings		(51,450,000,000)
Non-controlling interests		₩ (34,754,000,000)

Statement of Compliance - Addit

Statement of Compliance - Additional Information (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of initial application of standards or interpretations [line items]
Loss allowance	₩ 916,790		₩ 1,094,464	₩ 977,771	₩ 999,678
Retained earnings	44,160,659		42,974,658
Non-controlling interests	₩ 3,347,257		₩ 3,666,334
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member]
Disclosure of initial application of standards or interpretations [line items]
Retained earnings		₩ 447,067
Non-controlling interests		(34,754)
Increase (decrease) due to changes in accounting policy required by IFRS 9 [member] | Loans and receivables [member]
Disclosure of initial application of standards or interpretations [line items]
Loss allowance		107,454
Retained earnings		(51,450)
Non-controlling interests		₩ (34,754)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Estimated Useful Lives of Property, Plant and Equipment (Detail)	12 Months Ended
	Dec. 31, 2018
Bottom of range [member] | Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	5 years
Bottom of range [member] | Structures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	4 years
Bottom of range [member] | Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	4 years
Bottom of range [member] | Vehicles [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	3 years
Bottom of range [member] | Tools [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	3 years
Bottom of range [member] | Furniture and fixtures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	3 years
Bottom of range [member] | Finance lease assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	3 years
Top of range [member] | Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	50 years
Top of range [member] | Structures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	50 years
Top of range [member] | Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	25 years
Top of range [member] | Vehicles [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	20 years
Top of range [member] | Tools [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	10 years
Top of range [member] | Furniture and fixtures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	20 years
Top of range [member] | Finance lease assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	30 years
Top of range [member] | Bearer plants [member]
Disclosure of detailed information about property, plant and equipment [line items]
Estimated useful lives	20 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Estimated Useful Lives of Intangible Assets (Detail)	12 Months Ended
	Dec. 31, 2018
Intellectual property rights [member] | Bottom of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	4 years
Intellectual property rights [member] | Top of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	25 years
Development costs [member] | Bottom of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	3 years
Development costs [member] | Top of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	5 years
Port facilities usage rights [member] | Bottom of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	4 years
Port facilities usage rights [member] | Top of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	75 years
Other intangible assets [member] | Bottom of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	2 years
Other intangible assets [member] | Top of range [member]
Disclosure of detailed information about intangible assets [line items]
Estimated useful lives of intangible assets	15 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Additional Information (Detail) - Increase (decrease) due to application of IFRS 15 [member]	12 Months Ended
	Dec. 31, 2018
Disclosure of summary of significant accounting policies [Line Items]
Invoice payable description	Invoices are generally payable within 10 to 90 days
Construction contract payment description	The Company issues an invoice when the customer has completed the initial confirmation and generally the payment is made within 45 days from the invoice date.

Financial Risk Management - Net

Financial Risk Management - Net Borrowing-to-Equity Ratio (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Total borrowings	₩ 20,209,270	₩ 21,063,657
Less: Cash and cash equivalents	2,643,865	2,612,530
Net borrowings	17,565,405	18,451,127
Total equity	₩ 46,672,614	₩ 47,326,725	₩ 45,765,269	₩ 45,013,201
Net borrowings-to-equity ratio	37.64%	38.99%

Cash and Cash Equivalents - Sum

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Cash and cash equivalents [abstract]
Cash	₩ 1,668	₩ 1,896
Demand deposits and checking accounts	1,471,891	1,259,813
Time deposits	538,130	360,985
Other cash equivalents	632,176	989,836
Cash and cash equivalents	₩ 2,643,865	₩ 2,612,530

Cash and Cash Equivalents - S_2

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents - Additional Information (Detail) ₩ in Millions	Dec. 31, 2018KRW (₩)
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of Cash and Cash Equivalents [Line Items]
Cash equivalents, restricted	₩ 42,147

Trade Accounts and Notes Rece_3

Trade Accounts and Notes Receivable - Summary of Trade Accounts and Notes Receivables (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Current trade accounts and notes receivable	₩ 9,130,204	₩ 8,824,563
Non-current
Non-current trade accounts and notes receivable	427,125	731,570
Gross amount [member]
Current
Trade accounts and notes receivable	8,648,250	8,579,620
Finance lease receivables	57,487	10,469
Unbilled due from customers for contract work	810,655	728,007
Non-current
Trade accounts and notes receivable	583,797	871,432
Finance lease receivables	45,873	734
Allowance for credit losses [member]
Current
Current trade accounts and notes receivable	(386,188)	(493,533)
Non-current
Non-current trade accounts and notes receivable	₩ (202,545)	₩ (140,596)

Trade Accounts and Notes Rece_4

Trade Accounts and Notes Receivable - Additional Information (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Trade accounts and notes receivables, net [member]
Disclosure of financial assets [line items]
Trade accounts and notes receivable sold to financial institutions, for which the derecognition conditions were not met	₩ 468,706	₩ 309,964

Trade Accounts and Notes Rece_5

Trade Accounts and Notes Receivable - Finance Lease Receivables (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of finance lease and operating lease by lessor [line items]
Finance lease receivables	₩ 103,360	₩ 11,203
Rental contractor [member]
Disclosure of finance lease and operating lease by lessor [line items]
Finance lease receivables	₩ 103,360
Korea electric power corporation [member]
Disclosure of finance lease and operating lease by lessor [line items]
Finance lease receivables		10,469
Hystech.Co. Ltd. [member]
Disclosure of finance lease and operating lease by lessor [line items]
Finance lease receivables		₩ 734

Trade Accounts and Notes Rece_6

Trade Accounts and Notes Receivable - Gross Amount and Present Value of Minimum Lease Payments (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of finance lease and operating lease by lessor [line items]
Unrealized interest income	₩ (4,138)	₩ (1,396)
Present value of minimum lease payment	103,360	11,203
Less than 1 year [member]
Disclosure of finance lease and operating lease by lessor [line items]
Gross amount of lease payment	57,820	11,771
1 year - 5 years [member]
Disclosure of finance lease and operating lease by lessor [line items]
Gross amount of lease payment	₩ 49,678	₩ 828

Other Receivables - Summary of

Other Receivables - Summary of Other Receivables (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Other current receivables	₩ 1,385,629	₩ 1,636,006
Non-current
Other non-current receivables	863,240	879,176
Gross amount [member]
Current
Loans	236,782	617,696
Other accounts receivable	954,030	960,543
Accrued income	220,066	179,971
Deposits	108,640	107,137
Others	16,201	18,925
Non-current
Loans	731,344	874,158
Other accounts receivable	155,936	92,939
Accrued income	1,855	1,663
Deposits	152,072	122,485
Allowance for credit losses [member]
Current
Other current receivables	(150,090)	(248,266)
Non-current
Other non-current receivables	₩ (177,967)	₩ (212,069)

Other Financial Assets - Summar

Other Financial Assets - Summary of Other Financial Assets (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Derivatives assets held for trading	₩ 47,288	₩ 63,912
Debt securities	2,987
Financial assets held for trading		1,970
Current portion of held-to-maturity securities		421
Deposit instruments	1,931,518	1,297,769
Short-term financial instruments	6,099,303	5,545,667
Other current financial assets	8,081,096	7,045,880
Non-current
Derivatives assets held for trading	1,795	4,378
Equity securities	1,238,630
Debt securities	34,327
Other Securities	338,106
Held-to-maturity securities		4,790
Deposit instruments	35,040	60,542
Other non current financial assets	₩ 1,647,898	1,911,684
Debt securities [member]
Current
Available-for-sale securities		136,141
Non-current
Available-for-sale securities		54,439
Equity investments [member]
Non-current
Available-for-sale securities		1,730,753
Others [member]
Non-current
Available-for-sale securities		₩ 56,782

Other Financial Assets - Summ_2

Other Financial Assets - Summary of Other Financial Assets (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Government [member]
Disclosure of financial assets [line items]
Financial instruments restricted for use	₩ 5,715	₩ 10,080
Financial arrangements, pledge and others [member]
Disclosure of financial assets [line items]
Financial instruments restricted for use	73,935	78,477
Available-for-sale financial assets [member]
Disclosure of financial assets [line items]
Available-for-sale securities, respectively, have been provided as collateral for borrowings, construction projects and others	₩ 115,431	₩ 136,099

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of inventories [Line Items]
Inventories	₩ 12,153,303	₩ 10,793,781
Gross amount [member]
Disclosure of inventories [Line Items]
Finished goods	1,886,040	1,526,628
Merchandise	1,131,416	930,558
Semi-finished goods	1,945,567	1,721,130
Raw materials	2,821,972	2,329,268
Fuel and materials	888,941	808,016
Construction inventories	1,372,259	1,692,092
Materials-in-transit	2,245,740	1,818,576
Others	68,150	103,144
Inventories	12,360,085	10,929,412
Allowance for inventories valuation [member]
Disclosure of inventories [Line Items]
Inventories	₩ (206,782)	₩ (135,631)

Inventories - Changes of Allowa

Inventories - Changes of Allowance for Inventories Valuation (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Classes of current inventories [abstract]
Allowance for inventories valuation, beginning balance	₩ 135,631	₩ 203,164	₩ 231,378
Loss on valuation of inventories	141,799	78,560	152,249
Realization on disposal of inventories	(69,426)	(138,967)	(161,458)
Others	(1,222)	(7,126)	(19,005)
Allowance for inventories valuation, ending balance	₩ 206,782	₩ 135,631	₩ 203,164

Assets Held for Sale - Details

Assets Held for Sale - Details of Assets Held For Sale and Related Liabilities (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Property, plant and equipment	₩ 30,018,273	₩ 31,883,535	₩ 33,770,339
Assets held for sale	21,854	71,768
Assets held for sale and related liabilities [member]
Assets
Property, plant and equipment	21,076	71,732
Others		36
Posco [member]
Assets
Assets held for sale		392
Posco [member] | Assets held for sale and related liabilities [member]
Assets
Property, plant and equipment		392
Subsidiaries [member]
Assets
Other financial assets	778
Assets held for sale	21,854	71,376
Subsidiaries [member] | Assets held for sale and related liabilities [member]
Assets
Property, plant and equipment	₩ 21,076	71,340
Others		₩ 36

Assets Held for Sale - Detail_2

Assets Held for Sale - Details of Assets Held For Sale and Related Liabilities (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets and liabilities held for sale [Line Items]
Property, plant and equipment	₩ 30,018,273	₩ 31,883,535	₩ 33,770,339
Assets held for sale and related liabilities [member]
Assets and liabilities held for sale [Line Items]
Property, plant and equipment	₩ 21,076	71,732
Assets held for sale and related liabilities [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Assets and liabilities held for sale [Line Items]
Property, plant and equipment		₩ 71,340

Investments in Associates and_3

Investments in Associates and Joint Ventures - Summary of Investments in Associates and Joint Ventures (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments in subsidiaries, joint ventures and associates [abstract]
Investments in associates	₩ 1,738,692	₩ 1,520,441
Investments in joint ventures	1,911,311	2,037,491
Investments in associates and joint ventures	₩ 3,650,003	₩ 3,557,932	₩ 3,882,389

Investments in Associates and_4

Investments in Associates and Joint Ventures - Details of Investments in Associates (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)Companiesshares	Dec. 31, 2017KRW (₩)
Disclosure of associates [line items]
Investments in associates	₩ 1,738,692	₩ 1,520,441
Bottom of range [member]
Disclosure of associates [line items]
Ownership (%)	20.00%
Pospower Co Ltd [member]
Disclosure of associates [line items]
Percentage of shares disposed	63.53%
Domestic [member]
Disclosure of associates [line items]
Investments in associates	₩ 790,410	₩ 634,636
Domestic [member] | EQP POSCO Global No1 Natural Resources Private Equity Fund [member]
Disclosure of associates [line items]
Number of shares | shares	178,713,975,892
Ownership (%)	31.27%	31.14%
Investments in associates	₩ 174,123	₩ 175,553
Domestic [member] | Pospower Co Ltd [member]
Disclosure of associates [line items]
Number of shares | shares	4,507,138
Ownership (%)	34.00%
Investments in associates	₩ 161,477
Domestic [member] | SNNC [member]
Disclosure of associates [line items]
Number of shares | shares	18,130,000
Ownership (%)	49.00%	49.00%
Investments in associates	₩ 116,922	₩ 110,424
Domestic [member] | QSONE Co.,Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	200,000
Ownership (%)	50.00%	50.00%
Investments in associates	₩ 85,550	₩ 85,049
Domestic [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	16,098,143
Ownership (%)	45.67%	45.67%
Investments in associates	₩ 62,478	₩ 74,378
Domestic [member] | Chungju Enterprise City Development Co.,Ltd [member]
Disclosure of associates [line items]
Number of shares | shares	2,008,000
Ownership (%)	29.53%	29.53%
Investments in associates	₩ 17,382	₩ 17,252
Domestic [member] | Daesung Steel [member]
Disclosure of associates [line items]
Number of shares | shares	108,038
Ownership (%)	17.54%	17.54%
Investments in associates	₩ 15,644	₩ 15,500
Domestic [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	9,032,539
Ownership (%)	18.26%	18.26%
Investments in associates	₩ 13,329	₩ 31,660
Domestic [member] | Keystone-HYUNDAI SECURITIES NO. 1. Private Equity Fund [member]
Disclosure of associates [line items]
Number of shares | shares	13,800,000
Ownership (%)	40.45%
Investments in associates	₩ 11,183	₩ 12,379
Domestic [member] | KoFC POSCO HANWHA KB Shared Growth No. 2. Private Equity Fund [member]
Disclosure of associates [line items]
Number of shares | shares	6,485
Ownership (%)	12.50%	12.50%
Investments in associates	₩ 5,739	₩ 6,828
Domestic [member] | KONES, Corp. [member]
Disclosure of associates [line items]
Number of shares | shares	3,250,000
Ownership (%)	41.67%	41.67%
Investments in associates	₩ 2,849	₩ 2,827
Domestic [member] | Blue Ocean private equity fund [member]
Disclosure of associates [line items]
Number of shares | shares	333
Ownership (%)	27.52%	27.52%
Investments in associates		₩ 19,620
Domestic [member] | UITrans LRT Co., Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	7,714,380
Ownership (%)	38.19%	38.19%
Investments in associates		₩ 15,841
Domestic [member] | Other associates [member]
Disclosure of associates [line items]
Number of companies in other associates | Companies	46
Investments in associates	₩ 123,734	67,325
Domestic [member] | Acquisition cost [member] | EQP POSCO Global No1 Natural Resources Private Equity Fund [member]
Disclosure of associates [line items]
Investments in associates	178,787
Domestic [member] | Acquisition cost [member] | Pospower Co Ltd [member]
Disclosure of associates [line items]
Investments in associates	164,757
Domestic [member] | Acquisition cost [member] | SNNC [member]
Disclosure of associates [line items]
Investments in associates	90,650
Domestic [member] | Acquisition cost [member] | QSONE Co.,Ltd. [member]
Disclosure of associates [line items]
Investments in associates	84,395
Domestic [member] | Acquisition cost [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of associates [line items]
Investments in associates	80,491
Domestic [member] | Acquisition cost [member] | Chungju Enterprise City Development Co.,Ltd [member]
Disclosure of associates [line items]
Investments in associates	10,040
Domestic [member] | Acquisition cost [member] | Daesung Steel [member]
Disclosure of associates [line items]
Investments in associates	14,000
Domestic [member] | Acquisition cost [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of associates [line items]
Investments in associates	45,163
Domestic [member] | Acquisition cost [member] | Keystone-HYUNDAI SECURITIES NO. 1. Private Equity Fund [member]
Disclosure of associates [line items]
Investments in associates	13,800
Domestic [member] | Acquisition cost [member] | KoFC POSCO HANWHA KB Shared Growth No. 2. Private Equity Fund [member]
Disclosure of associates [line items]
Investments in associates	6,485
Domestic [member] | Acquisition cost [member] | KONES, Corp. [member]
Disclosure of associates [line items]
Investments in associates	6,893
Domestic [member] | Acquisition cost [member] | Blue Ocean private equity fund [member]
Disclosure of associates [line items]
Investments in associates	33,300
Domestic [member] | Acquisition cost [member] | UITrans LRT Co., Ltd. [member]
Disclosure of associates [line items]
Investments in associates	38,572
Foreign [member]
Disclosure of associates [line items]
Investments in associates	₩ 948,282	885,805
Foreign [member] | Other associates [member]
Disclosure of associates [line items]
Number of companies in other associates | Companies	29
Investments in associates	₩ 99,728	₩ 111,497
Foreign [member] | AES-VCM Mong Duong Power Company Limited [member]
Disclosure of associates [line items]
Ownership (%)	30.00%	30.00%
Investments in associates	₩ 209,936	₩ 142,348
Foreign [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	135,219,000
Ownership (%)	25.04%	25.04%
Investments in associates	₩ 179,459	₩ 197,069
Foreign [member] | 7623704 Canada Inc. [member]
Disclosure of associates [line items]
Number of shares | shares	114,452,000
Ownership (%)	10.40%	10.40%
Investments in associates	₩ 126,885	₩ 121,702
Foreign [member] | Eureka Moly LLC [member]
Disclosure of associates [line items]
Ownership (%)	20.00%	20.00%
Investments in associates	₩ 82,447	₩ 79,398
Foreign [member] | AMCI (WA) PTY LTD [member]
Disclosure of associates [line items]
Number of shares | shares	49
Ownership (%)	49.00%	49.00%
Investments in associates	₩ 71,086	₩ 63,378
Foreign [member] | Korea LNG Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	2,400
Ownership (%)	20.00%	20.00%
Investments in associates	₩ 43,554	₩ 33,422
Foreign [member] | Nickel mining company SAS [member]
Disclosure of associates [line items]
Number of shares | shares	3,234,698
Ownership (%)	49.00%	49.00%
Investments in associates	₩ 41,712	₩ 45,905
Foreign [member] | NCR LLC [member]
Disclosure of associates [line items]
Ownership (%)	29.41%	29.41%
Investments in associates	₩ 37,602	₩ 33,738
Foreign [member] | PT. batutua tembaga raya [member]
Disclosure of associates [line items]
Number of shares | shares	128,285
Ownership (%)	22.00%	22.00%
Investments in associates	₩ 20,479	₩ 21,823
Foreign [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of associates [line items]
Number of shares | shares	10,200,000
Ownership (%)	34.00%	34.00%
Investments in associates	₩ 14,796	₩ 15,617
Foreign [member] | PT. wampu electric power [member]
Disclosure of associates [line items]
Number of shares | shares	8,708,400
Ownership (%)	20.00%	20.00%
Investments in associates	₩ 14,120	₩ 13,391
Foreign [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of associates [line items]
Number of shares | shares	50
Ownership (%)	25.00%	25.00%
Investments in associates	₩ 6,478	₩ 6,517
Foreign [member] | Acquisition cost [member] | AES-VCM Mong Duong Power Company Limited [member]
Disclosure of associates [line items]
Investments in associates	164,303
Foreign [member] | Acquisition cost [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of associates [line items]
Investments in associates	135,899
Foreign [member] | Acquisition cost [member] | 7623704 Canada Inc. [member]
Disclosure of associates [line items]
Investments in associates	124,341
Foreign [member] | Acquisition cost [member] | Eureka Moly LLC [member]
Disclosure of associates [line items]
Investments in associates	240,123
Foreign [member] | Acquisition cost [member] | AMCI (WA) PTY LTD [member]
Disclosure of associates [line items]
Investments in associates	209,664
Foreign [member] | Acquisition cost [member] | Korea LNG Ltd. [member]
Disclosure of associates [line items]
Investments in associates	135,205
Foreign [member] | Acquisition cost [member] | Nickel mining company SAS [member]
Disclosure of associates [line items]
Investments in associates	157,585
Foreign [member] | Acquisition cost [member] | NCR LLC [member]
Disclosure of associates [line items]
Investments in associates	40,139
Foreign [member] | Acquisition cost [member] | PT. batutua tembaga raya [member]
Disclosure of associates [line items]
Investments in associates	21,824
Foreign [member] | Acquisition cost [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of associates [line items]
Investments in associates	9,517
Foreign [member] | Acquisition cost [member] | PT. wampu electric power [member]
Disclosure of associates [line items]
Investments in associates	10,054
Foreign [member] | Acquisition cost [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of associates [line items]
Investments in associates	₩ 4,723

Investments in Associates and_5

Investments in Associates and Joint Ventures - Details of Investments in Associates (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of associates [abstract]
Investment in associates provided as collateral for borrowings	₩ 285,066	₩ 158,370

Investments in Associates and_6

Investments in Associates and Joint Ventures - Details of Investments in Joint Ventures (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)	Dec. 31, 2017KRW (₩)Companiesshares
Disclosure of joint ventures [line items]
Investments in joint ventures	₩ 1,911,311	₩ 2,037,491
Foreign [member]
Disclosure of joint ventures [line items]
Investments in joint ventures	189,316	₩ 116,854
Foreign [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of joint ventures [line items]
Number of shares | shares		11,568,000
Ownership (%)		60.00%
Investments in joint ventures	180,192	₩ 110,760
Foreign [member] | Other joint ventures [member]
Disclosure of joint ventures [line items]
Number of companies in other joint ventures | Companies		6
Investments in joint ventures	₩ 9,124	₩ 6,094
Foreign [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of joint ventures [line items]
Ownership (%)	12.50%	12.50%
Foreign [member] | POSCO-NPS Niobium LLC [member]
Disclosure of joint ventures [line items]
Ownership (%)	50.00%	50.00%
Foreign [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of joint ventures [line items]
Ownership (%)	20.00%	20.00%
Foreign [member] | KOBRASCO [member]
Disclosure of joint ventures [line items]
Ownership (%)	50.00%	50.00%
Foreign [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of joint ventures [line items]
Ownership (%)	25.00%	25.00%
Foreign [member] | DMSA/AMSA [member]
Disclosure of joint ventures [line items]
Ownership (%)	4.00%	4.00%
Foreign [member] | Acquisition cost [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		₩ 115,680
Domestic [member]
Disclosure of joint ventures [line items]
Investments in joint ventures	₩ 1,721,995	₩ 1,920,637
Domestic [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of joint ventures [line items]
Ownership (%)	60.00%	60.00%
Domestic [member] | Other joint ventures [member]
Disclosure of joint ventures [line items]
Number of companies in other joint ventures | Companies		13
Investments in joint ventures	₩ 43,508	₩ 46,716
Domestic [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of joint ventures [line items]
Number of shares | shares		13,117,972
Ownership (%)		12.50%
Investments in joint ventures	1,041,600	₩ 1,125,133
Domestic [member] | POSCO-NPS Niobium LLC [member]
Disclosure of joint ventures [line items]
Number of shares | shares		325,050,000
Ownership (%)		50.00%
Investments in joint ventures	363,506	₩ 348,836
Domestic [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of joint ventures [line items]
Number of shares | shares		1,108,696,532
Ownership (%)		20.00%
Investments in joint ventures	24,832	₩ 146,427
Domestic [member] | KOBRASCO [member]
Disclosure of joint ventures [line items]
Number of shares | shares		2,010,719,185
Ownership (%)		50.00%
Investments in joint ventures	133,449	₩ 108,485
Domestic [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of joint ventures [line items]
Ownership (%)		25.00%
Investments in joint ventures	88,391	₩ 88,305
Domestic [member] | DMSA/AMSA [member]
Disclosure of joint ventures [line items]
Ownership (%)		4.00%
Investments in joint ventures	₩ 26,709	₩ 56,735
Domestic [member] | Acquisition cost [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		1,528,672
Domestic [member] | Acquisition cost [member] | POSCO-NPS Niobium LLC [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		364,609
Domestic [member] | Acquisition cost [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		558,821
Domestic [member] | Acquisition cost [member] | KOBRASCO [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		32,950
Domestic [member] | Acquisition cost [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		61,961
Domestic [member] | Acquisition cost [member] | DMSA/AMSA [member]
Disclosure of joint ventures [line items]
Investments in joint ventures		₩ 322,596

Investments in Associates and_7

Investments in Associates and Joint Ventures - Movements of Investments in Associates and Joint Ventures (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)Companies	Dec. 31, 2017KRW (₩)Companies	Dec. 31, 2016KRW (₩)
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	₩ 3,557,932	₩ 3,882,389
Acquisition	244,609	92,336
Dividends	(154,348)	(131,710)
Share of profits (losses)	112,635	10,540	₩ (88,677)
Other increase (decrease)	(110,825)	(295,623)
Book value, ending balance	3,650,003	3,557,932	3,882,389
Domestic [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	751,490	698,272
Acquisition	221,360	56,139
Dividends	(1,334)	(505)
Share of profits (losses)	25,500	11,918
Other increase (decrease)	(17,290)	(14,334)
Book value, ending balance	979,726	751,490	698,272
Domestic [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	110,760	83,113
Share of profits (losses)	69,594	27,582
Other increase (decrease)	(162)	65
Book value, ending balance	180,192	110,760	83,113
Domestic [member] | EQP POSCO Global No1 Natural Resources Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	175,553	175,690
Share of profits (losses)	(1,430)	418
Other increase (decrease)		(555)
Book value, ending balance	174,123	175,553	175,690
Domestic [member] | Pospower Co Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Acquisition	176,731
Share of profits (losses)	(3,198)
Other increase (decrease)	(12,056)
Book value, ending balance	161,477
Domestic [member] | SNNC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	110,424	107,859
Share of profits (losses)	6,624	2,370
Other increase (decrease)	(126)	195
Book value, ending balance	116,922	110,424	107,859
Domestic [member] | QSONE Co.,Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	85,049	84,799
Dividends	(550)	(368)
Share of profits (losses)	1,051	618
Book value, ending balance	85,550	85,049	84,799
Domestic [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	74,378	45,077
Acquisition		27,791
Share of profits (losses)	(11,900)	1,510
Book value, ending balance	62,478	74,378	45,077
Domestic [member] | Chungju Enterprise City Development Co.,Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	17,252	12,551
Share of profits (losses)	130	4,701
Book value, ending balance	17,382	17,252	12,551
Domestic [member] | Blue Ocean private equity fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	19,620	35,752
Share of profits (losses)	(17,930)	(8,154)
Other increase (decrease)	(1,690)	(7,978)
Book value, ending balance		19,620	35,752
Domestic [member] | Daesung Steel [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	15,500	12,302
Share of profits (losses)	144	3,198
Book value, ending balance	15,644	15,500	12,302
Domestic [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	31,660	37,372
Share of profits (losses)	(18,331)	(6,463)
Other increase (decrease)		751
Book value, ending balance	13,329	31,660	37,372
Domestic [member] | Keystone NO. 1. Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	12,379	13,314
Share of profits (losses)	(1,295)	(886)
Other increase (decrease)	99	(49)
Book value, ending balance	11,183	12,379	13,314
Domestic [member] | UITrans LRT Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	15,841	17,851
Share of profits (losses)	(15,841)	(2,010)
Book value, ending balance		15,841	17,851
Domestic [member] | KoFC POSCO HANWHA KB Shared Growth No. 2. Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	6,828	11,890
Share of profits (losses)	(1,089)	(197)
Other increase (decrease)		(4,865)
Book value, ending balance	5,739	6,828	11,890
Domestic [member] | KONES, Corp. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	2,827	5,641
Share of profits (losses)	29	(2,774)
Other increase (decrease)	(7)	(40)
Book value, ending balance	₩ 2,849	₩ 2,827	5,641
Domestic [member] | Other associates and joint ventures [member]
Disclosure of investments in associates and joint ventures [Line Items]
Number of companies in other associates and joint ventures | Companies	52	40
Book value, beginning balance	₩ 73,419	₩ 55,061
Acquisition	44,629	28,348
Dividends	(784)	(137)
Share of profits (losses)	18,942	(7,995)
Other increase (decrease)	(3,348)	(1,858)
Book value, ending balance	132,858	73,419	55,061
Foreign [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	2,806,442	3,184,117
Acquisition	23,249	36,197
Dividends	(153,014)	(131,205)
Share of profits (losses)	87,135	(1,378)
Other increase (decrease)	(93,535)	(281,289)
Book value, ending balance	2,670,277	2,806,442	3,184,117
Foreign [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	1,125,133	1,186,859
Share of profits (losses)	59,095	46,020
Other increase (decrease)	(142,628)	(107,746)
Book value, ending balance	1,041,600	1,125,133	1,186,859
Foreign [member] | POSCO-NPS Niobium LLC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	348,836	393,570
Dividends	(22,254)	(17,277)
Share of profits (losses)	21,536	17,173
Other increase (decrease)	15,388	(44,630)
Book value, ending balance	363,506	348,836	393,570
Foreign [member] | KOBRASCO [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	108,485	88,308
Dividends	(37,710)	(22,135)
Share of profits (losses)	75,170	56,445
Other increase (decrease)	(12,496)	(14,133)
Book value, ending balance	133,449	108,485	88,308
Foreign [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	88,305	97,369
Dividends		(5,542)
Share of profits (losses)	540	1,555
Other increase (decrease)	(454)	(5,077)
Book value, ending balance	88,391	88,305	97,369
Foreign [member] | DMSA/AMSA [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	56,735	74,935
Acquisition	17,973	13,712
Share of profits (losses)	(48,802)	(22,339)
Other increase (decrease)	803	(9,573)
Book value, ending balance	26,709	56,735	74,935
Foreign [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	146,427	330,463
Share of profits (losses)	(109,714)	(147,847)
Other increase (decrease)	(11,881)	(36,189)
Book value, ending balance	₩ 24,832	₩ 146,427	330,463
Foreign [member] | Other associates and joint ventures [member]
Disclosure of investments in associates and joint ventures [Line Items]
Number of companies in other associates and joint ventures | Companies	42	40
Book value, beginning balance	₩ 158,213	₩ 130,651
Acquisition	2,771	22,209
Dividends	(22,588)	(4,408)
Share of profits (losses)	42,937	46,535
Other increase (decrease)	(38,097)	(36,774)
Book value, ending balance	143,236	158,213	130,651
Foreign [member] | AES-VCM Mong Duong Power Company Limited [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	142,348	167,141
Dividends	(26,108)	(30,798)
Share of profits (losses)	30,096	19,644
Other increase (decrease)	63,600	(13,639)
Book value, ending balance	209,936	142,348	167,141
Foreign [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	197,069	215,996
Dividends	(29,301)	(37,016)
Share of profits (losses)	17,709	42,896
Other increase (decrease)	(6,018)	(24,807)
Book value, ending balance	179,459	197,069	215,996
Foreign [member] | 7623704 Canada Inc. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	121,702	137,512
Dividends	(4,509)	(7,563)
Share of profits (losses)	4,373	7,468
Other increase (decrease)	5,319	(15,715)
Book value, ending balance	126,885	121,702	137,512
Foreign [member] | Eureka Moly LLC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	79,398	89,601
Share of profits (losses)	(406)	(35)
Other increase (decrease)	3,455	(10,168)
Book value, ending balance	82,447	79,398	89,601
Foreign [member] | AMCI (WA) PTY LTD [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	63,378	70,501
Share of profits (losses)	(3,412)	(4,299)
Other increase (decrease)	11,120	(2,824)
Book value, ending balance	71,086	63,378	70,501
Foreign [member] | Korea LNG Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	33,422	63,058
Dividends	(10,544)	(6,466)
Share of profits (losses)	10,542	(70,180)
Other increase (decrease)	10,134	47,010
Book value, ending balance	43,554	33,422	63,058
Foreign [member] | Nickel mining company SAS [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	45,905	45,138
Share of profits (losses)	(4,268)	424
Other increase (decrease)	75	343
Book value, ending balance	41,712	45,905	45,138
Foreign [member] | NCR LLC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	33,738	36,738
Acquisition	2,505	276
Share of profits (losses)	(5,909)	(60)
Other increase (decrease)	7,268	(3,216)
Book value, ending balance	37,602	33,738	36,738
Foreign [member] | PT. batutua tembaga raya [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	21,823	22,723
Share of profits (losses)	(1,817)	260
Other increase (decrease)	473	(1,160)
Book value, ending balance	20,479	21,823	22,723
Foreign [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	15,617	18,008
Share of profits (losses)	(735)	(1,268)
Other increase (decrease)	(86)	(1,123)
Book value, ending balance	14,796	15,617	18,008
Foreign [member] | PT. wampu electric power [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	13,391	8,706
Share of profits (losses)	177	5,927
Other increase (decrease)	552	(1,242)
Book value, ending balance	14,120	13,391	8,706
Foreign [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Book value, beginning balance	6,517	6,840
Share of profits (losses)	23	303
Other increase (decrease)	(62)	(626)
Book value, ending balance	₩ 6,478	₩ 6,517	₩ 6,840

Investments in Associates and_8

Investments in Associates and Joint Ventures - Summarized Financial Information of Associates and Joint Ventures (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of investments in associates and joint ventures [Line Items]
Assets	₩ 78,776,991	₩ 79,785,629
Liabilities	32,104,377	32,458,904
Equity	46,672,614	47,326,725	₩ 45,765,269	₩ 45,013,201
Sales	65,154,636	60,186,867	52,939,771
Net income (loss)	1,932,386	2,909,311	₩ 1,032,065
Domestic [member] | POSCO MITSUBISHI CARBON TECHNOLOGY [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	537,138	478,847
Liabilities	237,563	295,052
Equity	299,575	183,795
Sales	300,986	154,312
Net income (loss)	116,049	46,138
Domestic [member] | EQP POSCO Global No1 Natural Resources Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	552,760	562,698
Liabilities	783	866
Equity	551,977	561,832
Net income (loss)	10,249	1,261
Domestic [member] | SNNC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	645,013	705,975
Liabilities	384,586	459,519
Equity	260,427	246,456
Sales	656,320	576,023
Net income (loss)	14,229	2,417
Domestic [member] | QSONE Co.,Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	249,384	248,779
Liabilities	78,285	78,680
Equity	171,099	170,099
Sales	16,597	15,297
Net income (loss)	2,101	1,236
Domestic [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	667,454	700,079
Liabilities	525,308	539,137
Equity	142,146	160,942
Sales	320,950	164,294
Net income (loss)	(18,796)	(8,250)
Domestic [member] | Daesung Steel [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	169,305	169,774
Liabilities	111,502	112,795
Equity	57,803	56,979
Sales	75,474	70,434
Net income (loss)	824	18,230
Domestic [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	1,049,629	1,132,233
Liabilities	931,937	922,338
Equity	117,692	209,895
Net income (loss)	(92,202)	(23,221)
Domestic [member] | Chungju Enterprise City Development Co.,Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	63,554	76,184
Liabilities	35,003	48,072
Equity	28,551	28,112
Sales	16,237	77,093
Net income (loss)	439	15,921
Domestic [member] | Blue Ocean private equity fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	305,876	311,129
Liabilities	174,640	188,512
Equity	131,236	122,617
Sales	459,491	445,238
Net income (loss)	(5,294)	(3,345)
Domestic [member] | Keystone NO. 1. Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	177,024	170,155
Liabilities	144,186	133,033
Equity	32,838	37,122
Sales	15,507	5,391
Net income (loss)	(3,962)	(2,070)
Domestic [member] | UITrans LRT Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	430,227	464,074
Liabilities	435,699	384,202
Equity	(5,472)	79,872
Sales	12,929	3,689
Net income (loss)	(85,344)	(13,263)
Domestic [member] | KoFC POSCO HANWHA KB Shared Growth No. 2. Private Equity Fund [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	59,464	55,936
Liabilities	1,061	1,315
Equity	58,403	54,621
Sales	2,401	10,212
Net income (loss)	(12,313)	(1,578)
Domestic [member] | KONES, Corp. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	2,618	2,766
Liabilities	1,414	1,616
Equity	1,204	1,150
Sales	5,167	5,379
Net income (loss)	70	139
Domestic [member] | Pospower Co Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	425,632
Liabilities	35,761
Equity	389,871
Net income (loss)	(4,536)
Foreign [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	9,666,619	10,148,416
Liabilities	6,043,492	6,600,900
Equity	3,623,127	3,547,516
Sales	3,259,256	2,988,372
Net income (loss)	497,469	797,008
Foreign [member] | POSCO-NPS Niobium LLC [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	726,810	697,470
Equity	726,810	697,470
Net income (loss)	41,812	32,481
Foreign [member] | KOBRASCO [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	317,842	252,813
Liabilities	50,945	35,843
Equity	266,897	216,970
Sales	229,340	179,453
Net income (loss)	150,550	112,890
Foreign [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	710,518	717,472
Liabilities	384,572	391,871
Equity	325,946	325,601
Sales	1,341,849	1,245,178
Net income (loss)	2,159	5,978
Foreign [member] | DMSA/AMSA [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	5,562,877	5,586,171
Liabilities	4,171,896	4,167,906
Equity	1,390,981	1,418,265
Sales	731,127	630,229
Net income (loss)	(529,844)	(475,958)
Foreign [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	4,194,242	4,805,353
Liabilities	4,192,867	4,223,392
Equity	1,375	581,961
Sales	1,860,198	1,290,767
Net income (loss)	(542,865)	(740,591)
Foreign [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	1,726,410	1,911,942
Liabilities	1,009,731	1,121,783
Equity	716,679	790,159
Sales	343,471	445,682
Net income (loss)	70,717	171,303
Foreign [member] | 7623704 Canada Inc. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	1,232,208	1,182,376
Liabilities	1	9
Equity	1,232,207	1,182,367
Net income (loss)	44,320	82,344
Foreign [member] | Korea LNG Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	217,883	179,269
Liabilities	110	86
Equity	217,773	179,183
Sales	54,357	34,640
Net income (loss)	52,720	32,446
Foreign [member] | Nickel mining company SAS [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	465,463	465,700
Liabilities	329,084	324,687
Equity	136,379	141,013
Sales	207,956	179,683
Net income (loss)	(4,569)	(4,450)
Foreign [member] | PT. batutua tembaga raya [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	332,305	336,085
Liabilities	274,580	272,542
Equity	57,725	63,543
Sales	128,609	195,520
Net income (loss)	(8,451)	49,091
Foreign [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	73,515	70,437
Liabilities	24,264	18,722
Equity	49,251	51,715
Sales	121,104	85,850
Net income (loss)	(2,231)	(3,736)
Foreign [member] | PT. wampu electric power [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	223,009	212,095
Liabilities	155,407	148,177
Equity	67,602	63,918
Sales	13,461	779
Net income (loss)	887	29,634
Foreign [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of investments in associates and joint ventures [Line Items]
Assets	61,782	70,701
Liabilities	34,740	43,588
Equity	27,042	27,113
Sales	85,619	84,973
Net income (loss)	₩ 78	₩ 1,210

Joint Operations - Details of S

Joint Operations - Details of Significant Joint Operations (Detail)	12 Months Ended
	Dec. 31, 2018
Myanmar A-1/A-3 mine [member]
Disclosure of joint operations [line items]
Category of business	Mineral development and gas production
Ownership (%)	51.00%
Location	Myanmar
Offshore midstream [member]
Disclosure of joint operations [line items]
Category of business	Gas transportation facility
Ownership (%)	51.00%
Location	Myanmar
Greenhills mine [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	20.00%
Location	Canada
Arctos Anthracite coal project [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	50.00%
Location	Canada
Mt. Thorley J/V [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	20.00%
Location	Australia
POSMAC J/V [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	20.00%
Location	Australia
RUM J/V [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	10.00%
Location	Australia
Hanam Gamil package public housing project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	7.70%
Location	Korea
Hanam-Gamil district B6, C2, C3 block Public housing lot development project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	27.00%
Location	Korea
Sejong 2-1 P3 Block public housing project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	37.00%
Location	Korea
Yongin-Giheung Station area city development project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	61.00%
Location	Korea
Korean wave world complex land multi-purpose building development project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	33.30%
Location	Korea
Sejong 4-1 P3 Block public housing project [member]
Disclosure of joint operations [line items]
Category of business	Construction
Ownership (%)	60.00%
Location	Korea

Investment Property, Net - Summ

Investment Property, Net - Summary of Investment Property (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about investment property [line items]
Investment property	₩ 928,615	₩ 1,064,914	₩ 1,117,720
Land [member]
Disclosure of detailed information about investment property [line items]
Investment property	278,585	360,402	392,723
Buildings [member]
Disclosure of detailed information about investment property [line items]
Investment property	571,335	634,040	671,539
Structures [member]
Disclosure of detailed information about investment property [line items]
Investment property	1,408	6,281	2,147
Construction-in-progress [member]
Disclosure of detailed information about investment property [line items]
Investment property	77,287	64,191	₩ 51,311
Gross amount [member]
Disclosure of detailed information about investment property [line items]
Investment property	1,081,838	1,159,332
Gross amount [member] | Land [member]
Disclosure of detailed information about investment property [line items]
Investment property	295,328	360,402
Gross amount [member] | Buildings [member]
Disclosure of detailed information about investment property [line items]
Investment property	681,518	727,022
Gross amount [member] | Structures [member]
Disclosure of detailed information about investment property [line items]
Investment property	3,327	7,717
Gross amount [member] | Construction-in-progress [member]
Disclosure of detailed information about investment property [line items]
Investment property	101,665	64,191
Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about investment property [line items]
Investment property	(153,223)	(94,418)
Accumulated depreciation, amortization and impairment [member] | Land [member]
Disclosure of detailed information about investment property [line items]
Investment property	(16,743)
Accumulated depreciation, amortization and impairment [member] | Buildings [member]
Disclosure of detailed information about investment property [line items]
Investment property	(110,183)	(92,982)
Accumulated depreciation, amortization and impairment [member] | Structures [member]
Disclosure of detailed information about investment property [line items]
Investment property	(1,919)	₩ (1,436)
Accumulated depreciation, amortization and impairment [member] | Construction-in-progress [member]
Disclosure of detailed information about investment property [line items]
Investment property	₩ (24,378)

Investment Property, Net - Addi

Investment Property, Net - Additional Information (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about investment property [line items]
Investment property	₩ 928,615	₩ 1,064,914	₩ 1,117,720
Fair value [member] | 6 Subsidiaries, including POSCO(Dalian) IT Center Development Co.,Ltd [member]
Disclosure of detailed information about investment property [line items]
Investment property	₩ 1,498,136

Investment Property, Net - Chan

Investment Property, Net - Changes in Carrying Amount of Investment Property (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about investment property [line items]
Beginning	₩ 1,064,914	₩ 1,117,720
Acquisitions	44,106	77,420
Disposals	(59,633)	(47,231)
Depreciation	(70,652)	(24,041)
Others	(50,120)	(58,954)
Ending	928,615	1,064,914
Land [member]
Disclosure of detailed information about investment property [line items]
Beginning	360,402	392,723
Acquisitions	1,327	20,941
Disposals	(26,826)	(37,725)
Depreciation	(16,743)
Others	(39,575)	(15,537)
Ending	278,585	360,402
Buildings [member]
Disclosure of detailed information about investment property [line items]
Beginning	634,040	671,539
Acquisitions	727	38,831
Disposals	(32,807)	(9,506)
Depreciation	(28,358)	(23,450)
Others	(2,267)	(43,374)
Ending	571,335	634,040
Structures [member]
Disclosure of detailed information about investment property [line items]
Beginning	6,281	2,147
Depreciation	(603)	(591)
Others	(4,270)	4,725
Ending	1,408	6,281
Construction-in-progress [member]
Disclosure of detailed information about investment property [line items]
Beginning	64,191	51,311
Acquisitions	42,052	17,648
Depreciation	(24,948)
Others	(4,008)	(4,768)
Ending	₩ 77,287	₩ 64,191

Investment Property, Net - Ch_2

Investment Property, Net - Changes in Carrying Amount of Investment Property (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about investment property [line items]
Impairment loss on investment property	₩ 51,461	₩ 0	₩ 318
POSCO(Dalian) IT Center Development Co., Ltd. [member]
Disclosure of detailed information about investment property [line items]
Impairment loss on investment property	₩ 51,461

Property, Plant and Equipment_3

Property, Plant and Equipment, Net - Summary of Property, Plant and Equipment (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	₩ 30,018,273	₩ 31,883,535	₩ 33,770,339
Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	68,802,624	67,499,667
Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(38,777,129)	(35,608,601)
Government grants	(7,222)	(7,531)
Land [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	2,548,002	2,527,650	2,601,208
Land [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	2,553,957	2,534,102
Land [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(5,955)	(6,452)
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	4,402,452	4,877,018	4,995,631
Buildings [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	9,146,294	9,311,426
Buildings [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(4,743,449)	(4,433,996)
Government grants	(393)	(412)
Structures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	2,917,924	2,765,852	2,908,480
Structures [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	5,884,277	5,452,713
Structures [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(2,966,304)	(2,686,802)
Government grants	(49)	(59)
Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	18,518,129	19,367,957	20,318,390
Machinery and equipment [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	47,610,225	46,669,612
Machinery and equipment [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(29,091,754)	(27,301,410)
Government grants	(342)	(245)
Vehicles [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	31,341	32,861	46,699
Vehicles [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	302,767	296,815
Vehicles [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(271,381)	(263,884)
Government grants	(45)	(70)
Tools [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	66,164	63,640	71,380
Tools [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	399,638	380,144
Tools [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(333,387)	(315,446)
Government grants	(87)	(1,058)
Furniture and fixtures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	136,287	145,439	132,406
Furniture and fixtures [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	638,553	643,779
Furniture and fixtures [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(502,215)	(498,192)
Government grants	(51)	(148)
Finance lease assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	137,564	145,257	159,013
Finance lease assets [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	213,873	243,160
Finance lease assets [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(76,309)	(97,903)
Bearer plants [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	80,771	65,515
Bearer plants [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	88,773	70,031
Bearer plants [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(8,002)	(4,516)
Construction-in-progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	1,179,639	1,892,346	₩ 2,537,132
Construction-in-progress [member] | Gross amount [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	1,964,267	1,897,885
Construction-in-progress [member] | Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(778,373)
Government grants	₩ (6,255)	₩ (5,539)

Property, Plant and Equipment_4

Property, Plant and Equipment, Net - Changes in Carrying Amount of Property, Plant and Equipment (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	₩ 31,883,535	₩ 33,770,339
Acquisitions	2,213,820	2,257,864
Disposals	(140,454)	(124,941)
Depreciation	(2,891,857)	(2,863,605)
Impairment loss	(997,198)	(117,231)
Others	(49,573)	(1,038,891)
Ending	30,018,273	31,883,535
Property plant and equipment	31,883,535	33,770,339
Land [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	2,527,650	2,601,208
Acquisitions	28,998	3,477
Disposals	(26,157)	(18,226)
Impairment loss	6,399
Others	11,112	(58,809)
Ending	2,548,002	2,527,650
Property plant and equipment	2,527,650	2,601,208
Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	4,877,018	4,995,631
Acquisitions	46,129	53,961
Disposals	(21,501)	(5,782)
Depreciation	(331,688)	(347,419)
Impairment loss	(73,523)	(14,112)
Others	(93,983)	194,739
Ending	4,402,452	4,877,018
Property plant and equipment	4,877,018	4,995,631
Structures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	2,765,852	2,908,480
Acquisitions	18,749	18,943
Disposals	(2,834)	(2,558)
Depreciation	(220,218)	(212,643)
Impairment loss	(6,652)	(33,586)
Others	363,027	87,216
Ending	2,917,924	2,765,852
Property plant and equipment	2,765,852	2,908,480
Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	19,367,957	20,318,390
Acquisitions	145,220	194,653
Disposals	(62,135)	(93,210)
Depreciation	(2,224,000)	(2,189,624)
Impairment loss	(143,293)	(27,811)
Others	1,434,380	1,165,559
Ending	18,518,129	19,367,957
Property plant and equipment	19,367,957	20,318,390
Machinery and equipment [member] | Synthetic Natural Gas [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Ending	167,054
Property plant and equipment	167,054
Vehicles [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	32,861	46,699
Acquisitions	8,538	9,982
Disposals	(1,149)	(1,623)
Depreciation	(14,835)	(17,363)
Impairment loss	(56)	(4,977)
Others	5,982	143
Ending	31,341	32,861
Property plant and equipment	32,861	46,699
Tools [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	63,640	71,380
Acquisitions	21,337	16,424
Disposals	(1,867)	(976)
Depreciation	(26,421)	(28,516)
Impairment loss	(206)	(23)
Others	9,681	5,351
Ending	66,164	63,640
Property plant and equipment	63,640	71,380
Furniture and fixtures [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	145,439	132,406
Acquisitions	32,258	61,597
Disposals	(577)	(1,296)
Depreciation	(51,835)	(48,400)
Impairment loss	(1,494)	(16)
Others	12,496	1,148
Ending	136,287	145,439
Property plant and equipment	145,439	132,406
Finance lease assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	145,257	159,013
Acquisitions	28,466	4,760
Disposals	(420)	(453)
Depreciation	(19,224)	(14,810)
Others	(16,515)	(3,253)
Ending	137,564	145,257
Property plant and equipment	145,257	159,013
Construction-in-progress [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	1,892,346	2,537,132
Acquisitions	1,884,125	1,894,067
Disposals	(23,814)	(817)
Impairment loss	(778,373)	(36,706)
Others	(1,794,645)	(2,501,330)
Ending	1,179,639	1,892,346
Property plant and equipment	1,892,346	2,537,132
Bearer plants [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning	65,515
Depreciation	(3,636)	(4,830)
Others	18,892	70,345
Ending	80,771	65,515
Property plant and equipment	₩ 65,515	₩ 65,515

Property, Plant and Equipment_5

Property, Plant and Equipment, Net - Changes in Carrying Amount of Property, Plant and Equipment (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss on property, plant and equipment	₩ 1,004,704	₩ 117,231	₩ 196,882
Synthetic Natural Gas [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss on property, plant and equipment	809,737
Fuel cell business [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss on property, plant and equipment	54,250	48,070
Individual assets based on disposal plans [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss on property, plant and equipment		₩ 17,651
Strip casting facilities [member]
Disclosure of detailed information about property, plant and equipment [line items]
Impairment loss on property, plant and equipment	₩ 61,787

Property, Plant and Equipment_6

Property, Plant and Equipment, Net - Borrowing Costs Capitalized and Capitalized Interest Rate (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [line items]
Expenditure	₩ 2,135,550	₩ 2,287,580	₩ 2,324,112
Borrowing costs capitalized	22,619	37,261
Weighted average [member]
Disclosure of detailed information about property, plant and equipment [line items]
Expenditure	₩ 628,595	₩ 1,180,563
Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Capitalization rate (%)	2.51%	1.74%
Top of range [member]
Disclosure of detailed information about property, plant and equipment [line items]
Capitalization rate (%)	3.90%	3.45%

Property, Plant and Equipment_7

Property, Plant and Equipment, Net - Property, Plant and Equipment and Investment Property Pledged as Collateral (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment and investment property pledged as collateral	₩ 5,711,500	₩ 6,043,269
Land [member] | Korean Development Bank and others [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment and investment property pledged as collateral	769,843	822,057
Buildings and structures [member] | Korean Development Bank and others [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment and investment property pledged as collateral	1,522,129	1,678,403
Machinery and equipment [member] | Korean Development Bank and others [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment and investment property pledged as collateral	₩ 3,419,528	3,527,420
Construction-in-progress [member] | Korean Development Bank and others [member]
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment and investment property pledged as collateral		₩ 15,389

Property, Plant and Equipment_8

Property, Plant and Equipment, Net - Property, Plant and Equipment and Investment Property Pledged as Collateral (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about property, plant and equipment [line items]
Assets pledged as collateral	₩ 5,711,500	₩ 6,043,269
Investment Property And Other Assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Assets pledged as collateral	₩ 5,323,071

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets, Net - Summary of Goodwill and Other Intangible Assets (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	₩ 5,170,825	₩ 5,952,269	₩ 6,088,729
Goodwill [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	1,125,149	1,349,838	1,375,131
Intellectual property rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	2,399,525	2,449,193	2,521,171
Premium in rental [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	134,793	118,310	119,039
Development costs [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	99,163	80,218	117,012
Port facilities usage rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	305,081	309,373	256,617
Exploration and evaluation assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	192,130	205,944	162,268
Customer relationships [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	421,773	466,945	514,245
Power generation permit [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets		539,405	539,405
Other intangible assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	493,211	433,043	₩ 483,841
Gross amount [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	8,494,949	8,686,709
Gross amount [member] | Goodwill [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	1,603,308	1,604,288
Gross amount [member] | Intellectual property rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	3,300,638	3,140,159
Gross amount [member] | Premium in rental [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	158,338	139,873
Gross amount [member] | Development costs [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	445,752	397,129
Gross amount [member] | Port facilities usage rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	724,375	705,692
Gross amount [member] | Exploration and evaluation assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	285,845	296,320
Gross amount [member] | Customer relationships [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	860,951	857,624
Gross amount [member] | Power generation permit [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets		539,405
Gross amount [member] | Other intangible assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	1,115,742	1,006,219
Accumulated depreciation, amortization and impairment [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(3,324,010)	(2,734,397)
Government grants	(114)	(43)
Accumulated depreciation, amortization and impairment [member] | Goodwill [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(478,159)	(254,450)
Accumulated depreciation, amortization and impairment [member] | Intellectual property rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(901,113)	(690,966)
Accumulated depreciation, amortization and impairment [member] | Premium in rental [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(23,545)	(21,563)
Accumulated depreciation, amortization and impairment [member] | Development costs [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(346,589)	(316,892)
Government grants		(19)
Accumulated depreciation, amortization and impairment [member] | Port facilities usage rights [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(419,294)	(396,319)
Accumulated depreciation, amortization and impairment [member] | Exploration and evaluation assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(93,715)	(90,376)
Accumulated depreciation, amortization and impairment [member] | Customer relationships [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(439,178)	(390,679)
Accumulated depreciation, amortization and impairment [member] | Other intangible assets [member]
Disclosure of detailed information about intangible assets [line items]
Goodwill and other intangible assets	(622,417)	(573,152)
Government grants	₩ (114)	₩ (24)

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets, Net - Changes in Carrying Amount of Goodwill and Other Intangible Assets (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	₩ 5,952,269	₩ 6,088,729
Acquisitions	542,359	353,115
Business combination		47,625
Disposals	(35,970)	(6,936)
Amortization	(356,581)	(409,774)
Impairment loss	(336,996)	(166,977)
Others	(594,256)	46,487
Ending	5,170,825	5,952,269
Goodwill [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	1,349,838	1,375,131
Impairment loss	(223,709)	(21,750)
Others	(980)	(3,543)
Ending	1,125,149	1,349,838
Intellectual property rights [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	2,449,193	2,521,171
Acquisitions	334,667	167,580
Business combination		47,625
Disposals	(18,619)	(450)
Amortization	(198,282)	(217,932)
Impairment loss	(96,475)	(74,524)
Others	(70,959)	5,723
Ending	2,399,525	2,449,193
Premium in rental [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	118,310	119,039
Acquisitions	36,196	6,006
Disposals	(15,675)	(3,666)
Amortization	(330)	(611)
Impairment loss	(4,218)	(1,661)
Others	510	(797)
Ending	134,793	118,310
Development costs [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	80,218	117,012
Acquisitions	4,248	3,479
Disposals	(32)	(1,179)
Amortization	(37,305)	(66,847)
Impairment loss	(411)	(694)
Others	52,445	28,447
Ending	99,163	80,218
Port facilities usage rights [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	309,373	256,617
Amortization	(22,975)	(19,912)
Others	18,683	72,668
Ending	305,081	309,373
Exploration and evaluation assets [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	205,944	162,268
Acquisitions	2,654	91,548
Impairment loss	(3,339)	(56,519)
Others	(13,129)	8,647
Ending	192,130	205,944
Customer relationships [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	466,945	514,245
Amortization	(48,499)	(46,508)
Others	3,327	(792)
Ending	421,773	466,945
Power generation permit [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	539,405	539,405
Others	(539,405)
Ending		539,405
Other intangible assets [member]
Disclosure of reconciliation of changes in intangible assets and goodwill [line items]
Beginning	433,043	483,841
Acquisitions	164,594	84,502
Disposals	(1,644)	(1,641)
Amortization	(49,190)	(57,964)
Impairment loss	(8,844)	(11,829)
Others	(44,748)	(63,866)
Ending	₩ 493,211	₩ 433,043

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets, Net - Allocation of Goodwill to Individually Operating Entities Which are Determined to be CGUs (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)Cash_Generating_Units	Dec. 31, 2017KRW (₩)Cash_Generating_Units
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Goodwill	₩ 1,125,149	₩ 1,349,838
Steel [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Total number of CGUs | Cash_Generating_Units	7	7
Trading [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Total number of CGUs | Cash_Generating_Units	2	2
Construction [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Total number of CGUs | Cash_Generating_Units	2	2
Other reportable segment [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Total number of CGUs | Cash_Generating_Units	5	5
Others [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Total number of CGUs | Cash_Generating_Units	16	16
POSCO VST Co., Ltd. [member] | Steel [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	POSCO VST CO., LTD.
Goodwill	₩ 36,955	₩ 36,955
Others [member] | Steel [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	Others
Goodwill	₩ 12,484	12,494
Others [member] | Trading [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	Others
Goodwill	₩ 16
Others [member] | Other reportable segment [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	Others
Goodwill	₩ 10,419	11,206
POSCO DAEWOO Corporation [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Discount rate	7.84%
Terminal growth rate	2.00%
Period for the estimated future cash flows	5 years
Impairment loss on goodwill	₩ 158,151
Discount rate increase	0.25%
Value in use decrease due to increase in discount rate	3.71%
Terminal growth rate decrease	0.25%
Value in use decrease due to decrease in terminal growth rate	1.49%
Value in use decrease due to increase in discount rate, amount	₩ 126,343
Value in use decrease due to decrease in terminal growth rate, amount	₩ 50,928
POSCO DAEWOO Corporation [member] | Trading [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	POSCO DAEWOO Corporation
Goodwill	₩ 1,006,879	1,165,030
PT. Bio Inti Agrindo [member] | Trading [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	PT. Bio Inti Agrindo
Goodwill	₩ 6,902	7,099
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
Terminal growth rate	9.10%
Period for the estimated future cash flows	5 years
Impairment loss on goodwill	₩ 65,558
Discount rate increase	0.25%
Value in use decrease due to increase in discount rate	2.72%
Terminal growth rate decrease	0.25%
Value in use decrease due to decrease in terminal growth rate	1.76%
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Construction [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	POSCO ENGINEERING & CONSTRUCTION CO., LTD.
Goodwill	₩ 24,868	90,426
POSCO ENERGY CO., LTD. [member] | Other reportable segment [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	POSCO ENERGY CO., LTD.
Goodwill	₩ 26,471	26,471
POSCO Center Beijing [member] | Construction [member]
Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]
CGUs	POSCO Center Beijing
Goodwill	₩ 155	₩ 157

Other Assets - Summary of Other

Other Assets - Summary of Other Current Assets and Other Non-Current Assets (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Advance payment	₩ 539,894	₩ 661,779
Prepaid expenses	123,770	143,032
Firm commitment asset	11,246	15,115
Others	9,554	1,316
Other current assets	684,464	821,242
Non-current
Long-term advance payment	24,280	24,201
Long-term prepaid expenses	334,918	333,153
Others	149,566	131,657
Other non-current assets	₩ 508,764	₩ 489,011

Other Assets - Summary of Oth_2

Other Assets - Summary of Other Current Assets and Other Non-Current Assets (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Subclassifications of assets, liabilities and equities [abstract]
Tax assets	₩ 88,633	₩ 88,633

Borrowings - Short-term Borrowi

Borrowings - Short-term Borrowings and Current Portion of Long-term Borrowings (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about borrowings [line items]
Short-term borrowings	₩ 7,487,780	₩ 8,174,818
Current portion of debentures	2,801,839	3,099,698
Current borrowings and current portion of non-current borrowings	10,289,619	11,274,516
JP Morgan and others [member]
Disclosure of detailed information about borrowings [line items]
Short-term borrowings	294,364	217,879
HSBC and others [member]
Disclosure of detailed information about borrowings [line items]
Short-term borrowings	₩ 7,193,416	7,956,939
Bottom of range [member] | Short-term borrowings [member] | JP Morgan and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	January, 2017
Maturity date	January, 2019
Interest rate (%)	2.70%
Bottom of range [member] | Short-term borrowings [member] | HSBC and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	January, 2018
Maturity date	January, 2019
Interest rate (%)	0.30%
Bottom of range [member] | Current portion of long-term liabilities [member] | Export-Import Bank of Korea and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	September, 2011
Maturity date	February, 2019
Interest rate (%)	0.50%
Bottom of range [member] | Current portion of long-term liabilities [member] | Korean Development Bank and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	August, 2009
Maturity date	February, 2019
Interest rate (%)	1.80%
Top of range [member] | Short-term borrowings [member] | JP Morgan and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	December, 2018
Maturity date	December, 2019
Interest rate (%)	8.90%
Top of range [member] | Short-term borrowings [member] | HSBC and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	December, 2018
Maturity date	December, 2019
Interest rate (%)	10.10%
Top of range [member] | Current portion of long-term liabilities [member] | Export-Import Bank of Korea and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	December, 2018
Maturity date	December, 2019
Interest rate (%)	8.80%
Top of range [member] | Current portion of long-term liabilities [member] | Korean Development Bank and others [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	March, 2018
Maturity date	December, 2019
Interest rate (%)	6.30%
Gross amount [member] | Export-Import Bank of Korea and others [member]
Disclosure of detailed information about borrowings [line items]
Current portion of debentures	₩ 1,234,915	1,407,123
Gross amount [member] | Korean Development Bank and others [member]
Disclosure of detailed information about borrowings [line items]
Current portion of debentures	1,568,108	1,693,974
Discount on debentures [member]
Disclosure of detailed information about borrowings [line items]
Current portion of debentures	₩ (1,184)	₩ (1,399)

Borrowings - Long-term Borrowin

Borrowings - Long-term Borrowings, Excluding Current Portion (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about borrowings [line items]
Long-term borrowings, excluding current portion	₩ 9,919,651	₩ 9,789,141
Export-Import Bank of Korea and others [member] | Long-term borrowings [member] | Bottom of range [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	September, 2001
Maturity date	March, 2020
Interest rate (%)	0.20%
Export-Import Bank of Korea and others [member] | Long-term borrowings [member] | Top of range [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	December, 2018
Maturity date	March, 2037
Interest rate (%)	8.80%
KB Securities and others [member] | Long-term borrowings [member] | Bottom of range [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	October, 2010
Maturity date	April, 2020
Interest rate (%)	1.90%
KB Securities and others [member] | Long-term borrowings [member] | Top of range [member]
Disclosure of detailed information about borrowings [line items]
Issuance date	November, 2018
Maturity date	July, 2025
Interest rate (%)	5.30%
Gross amount [member] | Export-Import Bank of Korea and others [member]
Disclosure of detailed information about borrowings [line items]
Long-term borrowings, excluding current portion	₩ 4,499,199	4,839,199
Gross amount [member] | KB Securities and others [member]
Disclosure of detailed information about borrowings [line items]
Long-term borrowings, excluding current portion	5,469,580	4,999,575
Present value discount [member]
Disclosure of detailed information about borrowings [line items]
Long-term borrowings, excluding current portion	30,526	36,459
Discount on debentures [member]
Disclosure of detailed information about borrowings [line items]
Long-term borrowings, excluding current portion	₩ 18,602	₩ 13,174

Borrowings - Summary of Assets

Borrowings - Summary of Assets Pledges as Collateral (Detail) ₩ in Millions	Dec. 31, 2018KRW (₩)
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	₩ 5,674,671
Book value [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	6,004,637
Property, plant and equipment including investment property [member] | Korean Development Bank and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	5,304,861
Property, plant and equipment including investment property [member] | Book value [member] | Korean Development Bank and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	5,592,627
Trade accounts and notes receivables, net [member] | Korean Development Bank and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	157,617
Trade accounts and notes receivables, net [member] | Book value [member] | Korean Development Bank and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	157,617
Inventories [member] | Export-Import Bank of Korea and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	163,233
Inventories [member] | Book value [member] | Export-Import Bank of Korea and others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	205,433
Cash and cash equivalents [member] | Shinhan Bank [member]
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	8,296
Cash and cash equivalents [member] | Book value [member] | Shinhan Bank [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	8,296
Shinhan Bank [member] | Kookmin Bank and Others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Pledged amount	40,664
Shinhan Bank [member] | Book value [member] | Kookmin Bank and Others [member]
Disclosure Of Assets Pledged As Collateral [line items]
Assets	₩ 40,664

Other Payables - Summary of Oth

Other Payables - Summary of Other Payables (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Accounts payable	₩ 783,562	₩ 800,374
Accrued expenses	720,773	653,923
Dividend payable	8,673	7,213
Finance lease liabilities	10,152	17,763
Withholdings	196,937	274,188
Other payables, current	1,720,097	1,753,461
Non-current
Accounts payable	1,624	4,632
Accrued expenses	19,021	14,234
Finance lease liabilities	84,602	75,255
Long-term withholdings	43,621	53,629
Other payables, non-current	₩ 148,868	₩ 147,750

Other Financial Liabilities - S

Other Financial Liabilities - Summary of Other Financial Liabilities (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Derivatives liabilities	₩ 27,328	₩ 69,872
Financial guarantee liabilities	50,472	59,940
Other financial liabilities, current	77,800	129,812
Non-current
Derivatives liabilities	46,429	85,638
Financial guarantee liabilities	17,733	28,467
Other financial liabilities, non-current	₩ 64,162	₩ 114,105

Provisions - Summary of Provisi

Provisions - Summary of Provisions (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of other provisions [line items]
Current	₩ 298,453	₩ 110,946
Non-current	431,036	477,172
Provision for bonus payments [member]
Disclosure of other provisions [line items]
Current	46,514	49,171
Non-current	26,964
Provision for construction warranties [member]
Disclosure of other provisions [line items]
Current	11,842	11,804
Non-current	130,391	106,232
Provision for legal contingencies and claims [member]
Disclosure of other provisions [line items]
Current	16,981	495
Non-current	55,716	36,269
Provisions for the restoration [member]
Disclosure of other provisions [line items]
Current	9,379	12,273
Non-current	79,789	121,917
Others [member]
Disclosure of other provisions [line items]
Current	213,737	37,203
Non-current	₩ 138,176	₩ 212,754

Provisions - Summary of Provi_2

Provisions - Summary of Provisions (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of other provisions [line items]
Other provisions	₩ 729,489	₩ 588,118	₩ 452,604
Others [member]
Disclosure of other provisions [line items]
Other provisions	351,913	249,957	₩ 165,469
Others [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of other provisions [line items]
Other provisions	200,407	157,461
Others [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of other provisions [line items]
Other provisions	17,595	23,600
Lawsuits provision [member]
Disclosure of other provisions [line items]
Other provisions	50,888	₩ 27,963
Land [member] | Gangneung province [member]
Disclosure of other provisions [line items]
Other provisions	₩ 29,703
Land [member] | Gangneung province [member] | Bottom of range [member]
Disclosure of other provisions [line items]
Discount rates	2.28%
Land [member] | Gangneung province [member] | Top of range [member]
Disclosure of other provisions [line items]
Discount rates	2.37%
Land [member] | Pohang work [member] | Bottom of range [member]
Disclosure of other provisions [line items]
Discount rates	2.28%
Land [member] | Pohang work [member] | Top of range [member]
Disclosure of other provisions [line items]
Discount rates	2.37%

Provisions - Changes in Provisi

Provisions - Changes in Provisions (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of other provisions [line items]
Beginning	₩ 588,118	₩ 452,604
Increase	573,472	367,595
Utilization	(218,997)	(225,861)
Reversal	(279,265)	(27,485)
Others	66,161	21,265
Ending	729,489	588,118
Provision for bonus payments [member]
Disclosure of other provisions [line items]
Beginning	49,171	42,986
Increase	88,879	74,728
Utilization	(60,723)	(64,319)
Reversal	(3,856)	(3,035)
Others	7	(1,189)
Ending	73,478	49,171
Provision for construction warranties [member]
Disclosure of other provisions [line items]
Beginning	118,036	96,709
Increase	56,560	40,916
Utilization	(24,608)	(18,006)
Reversal	(7,660)	(2,502)
Others	(95)	919
Ending	142,233	118,036
Provision for legal contingencies and claims [member]
Disclosure of other provisions [line items]
Beginning	36,764	84,846
Increase	45,789	27,459
Utilization	(6,066)	(70,156)
Reversal	(3,399)	(1,749)
Others	(391)	(3,636)
Ending	72,697	36,764
Provisions for the restoration [member]
Disclosure of other provisions [line items]
Beginning	134,190	62,594
Increase	14,912	63,438
Utilization	(9,212)	(8,530)
Reversal	(47,682)
Others	(3,040)	16,688
Ending	89,168	134,190
Others [member]
Disclosure of other provisions [line items]
Beginning	249,957	165,469
Increase	367,332	161,054
Utilization	(118,388)	(64,850)
Reversal	(216,668)	(20,199)
Others	69,680	8,483
Ending	₩ 351,913	₩ 249,957

Employee Benefits - Expense Rel

Employee Benefits - Expense Related to Post-employment Benefit Plans under Defined Contribution Plans (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of defined benefit plans [abstract]
Expense related to post-employment benefit plans under defined contribution plans	₩ 42,825	₩ 35,538	₩ 30,344

Employee Benefits - Amounts Rec

Employee Benefits - Amounts Recognized in Relation to Net Defined Benefit Liabilities in Statements of Financial Position (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of defined benefit plans [abstract]
Present value of funded obligations	₩ 2,117,829	₩ 1,826,907
Fair value of plan assets	(1,997,717)	(1,714,166)
Present value of non-funded obligations	19,332	16,228
Net defined benefit liabilities	₩ 139,444	₩ 128,969

Employee Benefits - Amounts R_2

Employee Benefits - Amounts Recognized in Relation to Net Defined Benefit Liabilities in Statements of Financial Position (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of defined benefit plans [abstract]
Net defined benefit assets	₩ 1,489	₩ 8,224

Employee Benefits - Changes in

Employee Benefits - Changes in Present Value of Defined Benefit Obligations (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of net defined benefit liability (asset) [line items]
Current service costs	₩ 212,323	₩ 209,612	₩ 285,706
Interest	4,166	(9,686)	1,901
Defined benefit obligations [member]
Disclosure of net defined benefit liability (asset) [line items]
Beginning of period	1,843,135	1,733,020
Current service costs	212,323	209,612
Interest	54,950	35,830
Remeasurements	212,678	51,994
- Gain from change in financial assumptions	173,084	(50,218)
- Loss (gain) from change in demographic assumptions	526	15,952
- Others	39,068	86,260
Benefits paid	(189,165)	(185,220)
Others	3,240	(2,101)
End of period	₩ 2,137,161	₩ 1,843,135	₩ 1,733,020

Employee Benefits - Changes i_2

Employee Benefits - Changes in Fair Value of Plan Assets (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of net defined benefit liability (asset) [line items]
Interest	₩ 4,166	₩ (9,686)	₩ 1,901
Plan assets [member]
Disclosure of net defined benefit liability (asset) [line items]
Beginning of period	1,714,166	1,693,118
Interest	50,784	45,516
Remeasurements	(19,761)	(17,190)
Contributions to plan assets	408,326	164,828
Benefits paid	(163,112)	(168,643)
Others	7,314	(3,463)
End of period	₩ 1,997,717	₩ 1,714,166	₩ 1,693,118

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)
Disclosure of net defined benefit liability (asset) [abstract]
Estimated contribution to the defined benefit plan assets	₩ 408,887

Employee Benefits - Fair Value

Employee Benefits - Fair Value of Plan Assets (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of fair value of plan assets [abstract]
Equity instruments	₩ 3,151	₩ 41,218
Debt instruments	692,825	367,027
Deposits	1,244,802	1,254,571
Others	56,939	51,350
Fair value of plan assets	₩ 1,997,717	₩ 1,714,166

Employee Benefits - Amounts R_3

Employee Benefits - Amounts Recognized in Consolidated Statements of Comprehensive Income (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of defined benefit plans [line items]
Current service costs	₩ 212,323	₩ 209,612	₩ 285,706
Net interest costs	4,166	(9,686)	1,901
Amounts recognized in consolidated statements of comprehensive income	216,489	199,926	287,607
Cost of sales [member]
Disclosure of defined benefit plans [line items]
Amounts recognized in consolidated statements of comprehensive income	150,822	131,724	161,810
Selling and administrative expenses [member]
Disclosure of defined benefit plans [line items]
Amounts recognized in consolidated statements of comprehensive income	64,505	67,424	124,994
Others [member]
Disclosure of defined benefit plans [line items]
Amounts recognized in consolidated statements of comprehensive income	₩ 1,162	₩ 778	₩ 803

Employee Benefits - Amounts R_4

Employee Benefits - Amounts Recognized in Consolidated Statements of Comprehensive Income (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of defined benefit plans [abstract]
Actual return on plan assets	₩ 31,023	₩ 28,326	₩ 30,422

Employee Benefits - Accumulated

Employee Benefits - Accumulated Actuarial Gains (Losses), Net of Tax Recognized in Other Comprehensive Income (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of defined benefit plans [abstract]
Beginning	₩ (299,155)	₩ (251,612)	₩ (272,152)
Current actuarial gains (losses)	(173,489)	(47,543)	20,540
Ending	₩ (472,644)	₩ (299,155)	₩ (251,612)

Employee Benefits - Principal A

Employee Benefits - Principal Actuarial Assumptions (Detail)	Dec. 31, 2018	Dec. 31, 2017
Bottom of range [member]
Disclosure of defined benefit plans [line items]
Discount rate	2.24%	2.70%
Expected future increase in salaries	2.54%	1.04%
Top of range [member]
Disclosure of defined benefit plans [line items]
Discount rate	10.03%	7.75%
Expected future increase in salaries	10.00%	10.00%

Employee Benefits - Changes to

Employee Benefits - Changes to Defined Benefit Obligation Due to Reasonably Possible Changes to one of the Relevant Actuarial Assumptions (Detail) ₩ in Millions	Dec. 31, 2018KRW (₩)
Discount rate [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Affect on defined benefit obligation due to reasonably possible 1% increase in actuarial assumption	₩ (143,793)
Percentage of reasonably possible 1% increase in actuarial assumption	(6.70%)
Affect on defined benefit obligation due to reasonably possible 1% decrease in actuarial assumption	₩ 166,225
Percentage of reasonably possible 1% decrease in actuarial assumption	7.80%
Expected future increase in salaries [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Affect on defined benefit obligation due to reasonably possible 1% increase in actuarial assumption	₩ 167,278
Percentage of reasonably possible 1% increase in actuarial assumption	7.80%
Affect on defined benefit obligation due to reasonably possible 1% decrease in actuarial assumption	₩ (147,232)
Percentage of reasonably possible 1% decrease in actuarial assumption	(6.90%)

Employee Benefits - Maturity of

Employee Benefits - Maturity of Expected Benefit Payments (Detail) ₩ in Millions	Dec. 31, 2018KRW (₩)
Disclosure of defined benefit plans [line items]
Benefits paid	₩ 2,968,389
Less than 1 year [member]
Disclosure of defined benefit plans [line items]
Benefits paid	110,168
1 year - 5 years [member]
Disclosure of defined benefit plans [line items]
Benefits paid	735,172
5 years - 10 years [member]
Disclosure of defined benefit plans [line items]
Benefits paid	836,318
10 years - 20 years [member]
Disclosure of defined benefit plans [line items]
Benefits paid	795,347
After 20 years [member]
Disclosure of defined benefit plans [line items]
Benefits paid	₩ 491,384

Other Liabilities - Summary of

Other Liabilities - Summary of Other Liabilities (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current
Due to customers for contract work	₩ 641,064	₩ 782,968
Advances received	1,130,910	1,183,108
Unearned revenue	49,805	7,121
Withholdings	233,981	221,940
Firm commitment liability	24,373	12,192
Others	10,174	33,590
Other current liabilities	2,090,307	2,240,919
Non-current
Advances received	148,081	357,981
Unearned revenue	42,992	18,440
Others	59,359	10,010
Other non-current liabilities	₩ 250,432	₩ 386,431

Financial Instruments - Summary

Financial Instruments - Summary of Carrying Amount and Fair Values of Financial Assets and Financial Liabilities by Fair value (Detail) ₩ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2018KRW (₩)	Dec. 31, 2017KRW (₩)	Dec. 31, 2017USD ($)
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Cash and cash equivalents		₩ 2,643,865	₩ 2,612,530
Derivative liabilities held for trading		73,757
Trade accounts and notes payable		4,035,960
Borrowings		7,487,780	8,174,818
Borrowings		20,209,270	21,063,657
Financial guarantee liabilities		68,205
Others		1,803,353
Short-term financial instruments		6,099,303	5,545,667
Other receivables		1,385,629	₩ 1,636,006
Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets		23,037,857		$ 22,663,736
Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial liabilities		26,190,545		26,650,935
Financial assets at fair value through profit or loss [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets held for trading | $	$ 1,970
Derivatives assets held for trading		16,662		65,051
Short-term financial instruments		6,099,303
Derivative hedging instruments | $				3,239
Debt securities		27,229
Available-for-sale financial assets | $				1,978,115
Other securities		338,106
Held-to-maturity investments | $				5,211
Other receivables		2,000
Derivative hedging instruments(*2)		32,421
Loans and receivables [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Cash and cash equivalents | $				2,612,530
Trade accounts and notes receivable | $				8,898,176
Loans and other receivables | $				9,099,444
Fair value through other comprehensive income [Member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Equity securities		1,238,630
Debt securities		1,638
Amortized cost [Member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Cash and cash equivalents		2,643,865
Trade accounts and notes receivable		8,819,617
Debt securities		8,447
Other receivables		1,843,381
Deposit instruments		1,966,558
Financial liabilities at fair value through profit or loss [Member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Fair value through profit or loss Derivative liabilities		60,047
Derivative liabilities held for trading | $				142,280
Derivative hedging instruments(*2)		13,710
Derivative hedging instruments | $				13,230
Financial liabilities measured at amortized cost [member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Trade accounts and notes payable		4,035,960
Trade accounts and notes payable | $				3,477,678
Borrowings		20,209,270
Borrowings | $				21,063,657
Financial guarantee liabilities		68,205		88,407
Others		1,803,353		1,865,683
Fair value [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets		7,755,989		2,048,375
Fair value [member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial liabilities		20,450,862		21,372,925
Fair value [member] | Financial assets at fair value through profit or loss [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets held for trading | $	1,970
Derivatives assets held for trading		16,662		65,051
Short-term financial instruments		6,099,303
Derivative hedging instruments | $				3,239
Debt securities		27,229
Available-for-sale financial assets | $				1,978,115
Other securities		338,106
Other receivables		2,000
Derivative hedging instruments(*2)		32,421
Fair value [member] | Fair value through other comprehensive income [Member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Equity securities		1,238,630
Debt securities		1,638
Fair value [member] | Financial liabilities at fair value through profit or loss [Member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Fair value through profit or loss Derivative liabilities		60,047
Derivative liabilities held for trading | $				142,280
Derivative hedging instruments(*2)		13,710
Derivative hedging instruments | $				13,230
Fair value [member] | Financial liabilities measured at amortized cost [member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Borrowings		20,377,105
Borrowings | $				21,217,415
Level 1 [member] | Fair value [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets		892,738		1,080,291
Level 1 [member] | Fair value [member] | Financial assets at fair value through profit or loss [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Available-for-sale financial assets | $				1,080,291
Other securities		1,224
Level 1 [member] | Fair value [member] | Fair value through other comprehensive income [Member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Equity securities		891,514
Level 2 [member] | Fair value [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets		6,153,591		88,072
Level 2 [member] | Fair value [member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial liabilities		20,450,862		21,372,925
Level 2 [member] | Fair value [member] | Financial assets at fair value through profit or loss [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets held for trading | $	$ 1,970
Derivatives assets held for trading		16,662		65,051
Short-term financial instruments		6,099,303
Derivative hedging instruments | $				3,239
Available-for-sale financial assets | $				17,812
Other securities		5,205
Derivative hedging instruments(*2)		32,421
Level 2 [member] | Fair value [member] | Financial liabilities at fair value through profit or loss [Member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Fair value through profit or loss Derivative liabilities		60,047
Derivative liabilities held for trading | $				142,280
Derivative hedging instruments(*2)		13,710
Derivative hedging instruments | $				13,230
Level 2 [member] | Fair value [member] | Financial liabilities measured at amortized cost [member] | Liabilities measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Borrowings		20,377,105
Borrowings | $				21,217,415
Level 3 [member] | Fair value [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Financial assets		709,660		880,012
Level 3 [member] | Fair value [member] | Financial assets at fair value through profit or loss [member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Debt securities		27,229
Available-for-sale financial assets | $				$ 880,012
Other securities		331,677
Other receivables		2,000
Level 3 [member] | Fair value [member] | Fair value through other comprehensive income [Member] | Assets measured at fair value [member]
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Equity securities		347,116
Debt securities		₩ 1,638

Financial Instruments - Value M

Financial Instruments - Value Measurement Method and Significant but not Observable Inputs for the Financial Assets Classified as Fair Value Hierarchy Level 3 (Detail) - Fair value [member] - Level 3 [member] ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)
Discounted cash flow [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Available-for-sale financial assets	₩ 303,377
PeerGroupUsage [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Available-for-sale financial assets	23,747
Asset value approach [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Available-for-sale financial assets	₩ 382,536
Available-for-sale financial assets [member] | Bottom of range [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Growth rate	0.00%
Discount rate	6.40%
Price multiple	1.085
Available-for-sale financial assets [member] | Top of range [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Growth rate	0.50%
Discount rate	13.80%
Price multiple	5.245

Financial Instruments - Sensiti

Financial Instruments - Sensitivity Analysis of Financial Assets and Financial Liabilities Classified as Level 3 of Fair Value Hierarchy (Detail) - Available-for-sale financial assets [member] ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)
Fluctuation 0.5% of growth rate [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Favorable changes	₩ 1,563
Unfavorable changes	958
Fluctuation 0.5% of discount rate [member]
Disclosure of significant unobservable inputs used in fair value measurement of assets [line items]
Favorable changes	17,332
Unfavorable changes	₩ 15,715

Financial Instruments - Changes

Financial Instruments - Changes in Fair Value of Financial Assets and Financial Liabilities Classified as Level 3 (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of fair value measurement of assets [line items]
Beginning	₩ 79,785,629
Impairment		₩ (123,214)	₩ (248,404)
Ending	78,776,991	79,785,629
Fair value [member] | Level 3 [member]
Disclosure of fair value measurement of assets [line items]
Beginning	880,012	349,090
Acquisition and others	134,325	658,359
Gain (loss) on valuations of derivatives	(34,555)	(10,346)
Other comprehensive income (loss)	26,771	35,126
Impairment		(107,934)
Disposal and others	(296,893)	(44,283)
Ending	₩ 709,660	₩ 880,012	₩ 349,090

Financial Instruments - Finance

Financial Instruments - Finance Income and Costs by Category of Financial Instruments (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)	₩ (404,038)	₩ (440,664)	₩ (476,251)
Gain and loss on valuation	13,019	(161,735)	(15,565)
Gain and loss on foreign currency	(204,102)	170,098	(142,308)
Gain and loss on disposal	10,690	360,787	87,819
Impairment loss		(123,214)	(248,404)
Others	45,985	83,118	12,499
Total	(538,446)	(111,610)	(782,210)
Other comprehensive income (loss)	(149,400)	(31,532)	310,608
Derivative financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Gain and loss on valuation	8,592	(61,809)	(72,976)
Gain and loss on disposal	(194,446)	(231,908)	(332,415)
Total	(185,854)	(293,717)	(405,391)
Other comprehensive income (loss)	(212)
Financial liabilities measured at amortized cost [member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)	(741,296)	(653,115)	(658,726)
Gain and loss on foreign currency	(438,708)	777,935	(283,059)
Gain and loss on disposal			(61)
Others	(16,990)	(9,546)	(28,367)
Total	(1,196,994)	115,274	(970,213)
Derivative financial assets [member]
Disclosure of detailed information about financial instruments [line items]
Gain and loss on valuation	47,720	(99,942)	57,411
Gain and loss on disposal	233,187	206,362	310,625
Total	280,907	106,420	368,036
Other comprehensive income (loss)		(143)
Available-for-sale financial assets [member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)		60	431
Gain and loss on disposal		418,789	127,524
Impairment loss		(123,214)	(248,404)
Others		92,961	41,000
Total		388,596	(79,449)
Other comprehensive income (loss)		(31,389)	310,608
Held-to-maturity financial assets [member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)		236	266
Others		7	38
Total		243	304
Loans and receivables [member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)		212,155	181,778
Gain and loss on foreign currency		(607,837)	140,751
Gain and loss on disposal		(32,456)	(17,854)
Others		(304)	(172)
Total		(428,442)	₩ 304,503
Financial assets held for trading [member]
Disclosure of detailed information about financial instruments [line items]
Gain and loss on valuation		16
Total		₩ 16
Financial assets at fair value through profit or loss [member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)	140,116
Gain and loss on valuation	(43,293)
Gain and loss on disposal	11,919
Others	3,644
Total	112,386
Fair value through other comprehensive income [Member]
Disclosure of detailed information about financial instruments [line items]
Others	59,701
Total	59,701
Other comprehensive income (loss)	(149,188)
Amortized cost [Member]
Disclosure of detailed information about financial instruments [line items]
Interest income (expense)	197,142
Gain and loss on foreign currency	234,606
Gain and loss on disposal	(39,970)
Others	(370)
Total	₩ 391,408

Financial Instruments - Maximum

Financial Instruments - Maximum Exposure to Credit Risk (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	₩ 21,799,227	₩ 20,878,487
Cash and cash equivalents [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,643,865	2,612,530
Derivative financial assets [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	49,083	68,290
Short-term financial instrument [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	6,099,303	5,545,667
Debt securities [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	37,314
Other securities [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	338,106
Fair value through profit or loss [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,970
Available for sale financial assets [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		192,866
Held to maturity investments [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		5,211
Other receivables [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,845,381	2,195,466
Trade accounts and notes receivables, net [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	8,819,617	8,898,176
Deposit instruments [member]
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	₩ 1,966,558	₩ 1,358,311

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about financial instruments [line items]
Maximum exposure to credit risk related financial guarantees	₩ 21,799,227	₩ 20,878,487
Financial guarantees [member]
Disclosure of detailed information about financial instruments [line items]
Maximum exposure to credit risk related financial guarantees	₩ 3,147,280	₩ 3,135,084

Financial Instruments - Allowan

Financial Instruments - Allowance for Doubtful Accounts (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of financial assets [line items]
Allowance for doubtful accounts	₩ 916,790	₩ 1,094,464	₩ 977,771	₩ 999,678
Trade accounts and notes receivables, net [member]
Disclosure of financial assets [line items]
Allowance for doubtful accounts	588,733	634,129
Other accounts receivable [member]
Disclosure of financial assets [line items]
Allowance for doubtful accounts	160,729	187,706
Loans [member]
Disclosure of financial assets [line items]
Allowance for doubtful accounts	147,980	258,957
Other assets [member]
Disclosure of financial assets [line items]
Allowance for doubtful accounts	₩ 19,348	₩ 13,672

Financial Instruments - Impairm

Financial Instruments - Impairment Losses on Financial Assets (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of financial assets [line items]
Impairment loss on financial assets		₩ 123,214	₩ 248,404
Impairment loss on financial assets, net	₩ 137,873	395,065
Bad debt expenses [member]
Disclosure of financial assets [line items]
Impairment loss on financial assets	74,781	173,694
Others [member]
Disclosure of financial assets [line items]
Impairment loss on financial assets	81,353	100,920
Less: Recovery of impairment loss on financial assets	₩ (18,261)	(2,743)
Available-for-sale financial assets [member]
Disclosure of financial assets [line items]
Impairment loss on financial assets		123,214
Held-to-maturity financial assets [member]
Disclosure of financial assets [line items]
Less: Recovery of impairment loss on financial assets		₩ (20)

Financial Instruments - Aging a

Financial Instruments - Aging and Impairment Losses of Trade Accounts and Notes Receivable and Other Receivables (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of financial assets that are either past due or impaired [line items]
Allowance for doubtful accounts	₩ 916,790	₩ 1,094,464	₩ 977,771	₩ 999,678
Trade accounts and notes receivables, net [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	10,146,062	10,190,262
Allowance for doubtful accounts	588,733	634,129
Trade accounts and notes receivables, net [member] | Not due [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	8,021,110	7,736,092
Allowance for doubtful accounts	70,418	65,314
Trade accounts and notes receivables, net [member] | Overdue less than 1 month [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	632,082	445,390
Allowance for doubtful accounts	14,434	12,546
Trade accounts and notes receivables, net [member] | 1 month-3 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	226,082	170,682
Allowance for doubtful accounts	4,116	742
Trade accounts and notes receivables, net [member] | 3 months-12 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	118,094	384,313
Allowance for doubtful accounts	11,774	21,030
Trade accounts and notes receivables, net [member] | Over 12 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	1,148,694	1,453,785
Allowance for doubtful accounts	487,991	534,497
Other receivables [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	2,173,438	2,655,801
Allowance for doubtful accounts	328,057	460,335
Other receivables [member] | Not due [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	1,754,293	1,888,726
Allowance for doubtful accounts	140,072	9,672
Other receivables [member] | Overdue less than 1 month [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	100,102	235,559
Allowance for doubtful accounts	4,307	35,539
Other receivables [member] | 1 month-3 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	28,351	69,372
Allowance for doubtful accounts	851	54,335
Other receivables [member] | 3 months-12 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	59,946	96,942
Allowance for doubtful accounts	12,411	64,467
Other receivables [member] | Over 12 months [member]
Disclosure of financial assets that are either past due or impaired [line items]
Financial assets	230,746	365,202
Allowance for doubtful accounts	₩ 170,416	₩ 296,322

Financial Instruments - Chang_2

Financial Instruments - Changes in Allowance for Doubtful Accounts (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of changes in allowance account for credit losses of financial assets [abstract]
Beginning	₩ 1,094,464	₩ 977,771	₩ 999,678
Initial application of IFRS No.9	107,454
Bad debt expenses	74,781	173,694	165,150
Other bad debt expenses	63,092	98,177	37,567
Others	(423,001)	(155,178)	(224,624)
Ending	₩ 916,790	₩ 1,094,464	₩ 977,771

Financial Instruments - Chang_3

Financial Instruments - Changes in Allowance for Doubtful Accounts (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of changes in allowance account for credit losses of financial assets [abstract]
Write-off of receivables	₩ 383,714	₩ 119,964	₩ 216,657

Financial Instruments - Contrac

Financial Instruments - Contractual Maturities for Non-derivative Financial Liabilities (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Trade accounts and notes payable, book value	₩ 4,035,960
Borrowings, book value	20,209,270	₩ 21,063,657
Financial guarantee liabilities, book value	68,205
Other financial liabilities, book value	1,803,353
Non-derivative financial liabilities, book value	26,116,788
Trade accounts and notes payable, contractual cash flow	4,037,863
Borrowings, contractual cash flow	24,319,619
Financial guarantee liabilities, contractual cash flow	3,147,280
Other financial liabilities, contractual cash flow	1,817,014
Non-derivative financial liabilities, contractual cash flow	33,321,776
Less than 1 year [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Trade accounts and notes payable, contractual cash flow	4,006,942
Borrowings, contractual cash flow	12,912,399
Financial guarantee liabilities, contractual cash flow	3,147,280
Other financial liabilities, contractual cash flow	1,668,937
Non-derivative financial liabilities, contractual cash flow	21,735,558
1 year - 5 years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Trade accounts and notes payable, contractual cash flow	30,921
Borrowings, contractual cash flow	10,452,389
Other financial liabilities, contractual cash flow	148,077
Non-derivative financial liabilities, contractual cash flow	10,631,387
After 5 years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Borrowings, contractual cash flow	954,831
Non-derivative financial liabilities, contractual cash flow	₩ 954,831

Financial Instruments - Maturit

Financial Instruments - Maturity Analysis of Derivative Financial Liabilities (Detail) ₩ in Millions	Dec. 31, 2018KRW (₩)
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	₩ 73,757
Currency forward [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	46,107
Currency swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	11,925
Interest swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	1,467
Others [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	14,258
Less than 1 year [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	27,329
Less than 1 year [member] | Currency forward [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	11,364
Less than 1 year [member] | Currency swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	1,707
Less than 1 year [member] | Others [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	14,258
1 year - 5 years [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	42,059
1 year - 5 years [member] | Currency forward [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	34,743
1 year - 5 years [member] | Currency swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	5,849
1 year - 5 years [member] | Interest swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	1,467
After 5 years [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	4,369
After 5 years [member] | Currency swap [member]
Disclosure of maturity analysis for derivative financial liabilities [line items]
Derivative financial liabilities	₩ 4,369

Financial Instruments - Exposur

Financial Instruments - Exposure to Currency Risk (Detail) - Currency risk [member] - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
USD [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Assets	₩ 4,346,481	₩ 4,215,151
Liabilities	6,389,276	5,940,380
EUR [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Assets	657,690	552,630
Liabilities	509,437	454,072
JPY [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Assets	97,722	165,356
Liabilities	389,625	709,318
Others [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Assets	259,949	220,723
Liabilities	₩ 142,868	₩ 117,632

Financial Instruments - Chang_4

Financial Instruments - Changes in Gain or Loss Due to a Hypothetically Strengthening or Weakening in Foreign Currencies (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
10% increase [member] | USD [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ (204,280)	₩ (172,523)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%
10% increase [member] | EUR [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ 14,825	9,856
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%
10% increase [member] | JPY [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ (29,190)	(54,396)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%
10% decrease [member] | USD [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ 204,280	172,523
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%
10% decrease [member] | EUR [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ (14,825)	(9,856)
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%
10% decrease [member] | JPY [member]
Disclosure of detailed information about hedging instruments [line items]
Changes in gain or loss due to hypothetically strengthens or weakens of functional currency against foreign currencies other than functional currency		₩ 29,190	₩ 54,396
Hypothetical percentage change in functional currency against foreign currencies other than functional currency	10.00%	10.00%

Financial Instruments - Carryin

Financial Instruments - Carrying Amount of Interest-Bearing Financial Instruments (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fixed rate [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Financial assets	₩ 11,565,519	₩ 10,943,300
Financial liabilities	(11,781,701)	(11,179,635)
Financial asset and liabilities	(216,182)	(236,335)
Variable rate [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Financial liabilities	₩ (8,522,323)	₩ (9,977,040)

Financial Instruments - Chang_5

Financial Instruments - Changes in Interest Expense Due to an Increases or Decreases in Interest Rate (Detail) - Variable rate [member] - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
1% increase in floating rates [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Hypothetical percentage change in the floating rate	1.00%	1.00%
Change in interest expense due to hypothetical increase or decrease in the floating rate	₩ (85,223)	₩ (99,770)
1% decrease in floating rates [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Hypothetical percentage change in the floating rate	(1.00%)	(1.00%)
Change in interest expense due to hypothetical increase or decrease in the floating rate	₩ 85,223	₩ 99,770

Share Capital and Capital Sur_3

Share Capital and Capital Surplus - Summary of Share Capital (Detail) - KRW (₩) ₩ / shares in Units, ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of classes of share capital [abstract]
Authorized shares	200,000,000	200,000,000
Par value	₩ 5,000	₩ 5,000
Issued shares(*1)	87,186,835	87,186,835	87,186,835
Shared capital(*2)	₩ 482,403	₩ 482,403

Share Capital and Capital Sur_4

Share Capital and Capital Surplus - Summary of Share Capital (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of classes of share capital [line items]
Total shares of ADRs outstanding	80,001,132	79,999,604	79,997,665
Total shares of ADRs outstanding, equivalent common stock shares	9,215,072
Difference between the ending balance of common stock and the par value of issued common stock due to retirement of treasury stocks	₩ 46,469
Retirement of treasury stock	9,293,790
ADRs [member]
Disclosure of classes of share capital [line items]
Total shares of ADRs outstanding	36,860,288

Share Capital and Capital Sur_5

Share Capital and Capital Surplus - Changes in Issued Common Stock (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of classes of share capital [abstract]
Shares issued beginning balance	87,186,835	87,186,835
Disposal of treasury shares	0	0
Shares issued ending balance	87,186,835	87,186,835
Treasury shares beginning balance	(7,187,231)	(7,189,170)
Disposal of treasury shares	1,528	1,939
Treasury shares ending balance	(7,185,703)	(7,187,231)
Number of outstanding shares beginning balance	79,999,604	79,997,665
Disposal of treasury shares	1,528	1,939
Number of outstanding shares ending balance	80,001,132	79,999,604

Share Capital and Capital Sur_6

Share Capital and Capital Surplus - Summary of Capital Surplus (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of changes in equity [abstract]
Share premium	₩ 463,825	₩ 463,825
Gain on disposal of treasury shares	784,047	783,914
Other capital deficit	172,135	174,282
Capital surplus	₩ 1,420,007	₩ 1,422,021

Share Capital and Capital Sur_7

Share Capital and Capital Surplus - Summary of Redeemable Convertible Preferred Shares (Detail) - Redeemable convertible preferred stock [member]	12 Months Ended
	Dec. 31, 2018₩ / sharesshares
Disclosure Of Redeemable Convertible Preferred Shares [line items]
Issue date	Feb. 25, 2017
Number of shares issued | shares	8,643,193
Price per share | ₩ / shares	₩ 28,346
Voting rights	No voting rights for 3 years from issue date
Dividend rights	Comparative, Non-participating
Dividend rate description	Minimum dividend rate for 1~3 years : 3.98%
Dividend rate	3.98%
Dividend rate issuance spread on comparative rate	Minimum dividend rate after 4 years : Comparative rate + Issuance spread + 2%
Details about redemption	Issuer can demand redemption of all or part of redeemable convertible preferred shares every year after the issue date, for a period of 10 years from the issue date.
Details about Conversion	Stockholders of redeemable convertible preferred shares can convert them to common shares from 3 years after the issue date to the end of the redemption period (10 years). Conversion price is equal to issue price per share, which could be adjusted according to anti-dilution clause.

Hybrid Bonds - Summary of Hybri

Hybrid Bonds - Summary of Hybrid Bonds (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about borrowings [line items]
Hybrid bonds classified as equity	₩ 199,384	₩ 996,919
Hybrid bond 1-1 [member]
Disclosure of detailed information about borrowings [line items]
Date of issue	-
Date of maturity	-
Hybrid bond 1-2 [member]
Disclosure of detailed information about borrowings [line items]
Date of issue	Jun. 13, 2013
Date of maturity	Jun. 13, 2043
Interest rate (%)	4.60%
Gross amount [member] | Hybrid bond 1-1 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bonds classified as equity		800,000
Gross amount [member] | Hybrid bond 1-2 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bonds classified as equity	₩ 200,000	200,000
Issuance cost [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bonds classified as equity	₩ (616)	₩ (3,081)

Hybrid Bonds - Summary of Hyb_2

Hybrid Bonds - Summary of Hybrid Bonds (Parenthetical) (Detail) - Hybrid bond 1-2 [member]	12 Months Ended
	Dec. 31, 2018KRW (₩)
Disclosure of detailed information about borrowings [line items]
Maturity date	30 years (POSCO has a right to extend the maturity date)
Interest rate	₩ 0
Interest rate adjustment	4.60%
Interest payments condition	Quarterly (Optional deferral of interest payment is available to POSCO)
Others	POSCO can call the hybrid bond at year 10 and interest payment date afterwards
After 10 years [member]
Disclosure of detailed information about borrowings [line items]
Interest rate adjustment	0.25%
After 10 years : Return on Government Bond [member]
Disclosure of detailed information about borrowings [line items]
Interest rate adjustment	1.40%
After 30 years [member]
Disclosure of detailed information about borrowings [line items]
Interest rate adjustment	0.75%

Hybrid Bonds - Additional Infor

Hybrid Bonds - Additional Information (Detail) - Hybrid bonds [member] ₩ in Millions	Dec. 31, 2018KRW (₩)
Disclosure of detailed information about borrowings [line items]
Interest accumulated but not paid on hybrid bonds	₩ 479
POSCO ENERGY CO., LTD. [member]
Disclosure of detailed information about borrowings [line items]
Interest accumulated but not paid on hybrid bonds	₩ 639

Hybrid Bonds - Hybrid Bonds Iss

Hybrid Bonds - Hybrid Bonds Issued by POSCO ENERGY Co., Ltd. (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about borrowings [line items]
Hybrid bond	₩ 199,384	₩ 996,919
Hybrid bond 1-1 [member]
Disclosure of detailed information about borrowings [line items]
Date of issue	-
Date of maturity	-
Hybrid bond 1-2 [member]
Disclosure of detailed information about borrowings [line items]
Date of issue	Jun. 13, 2013
Date of maturity	Jun. 13, 2043
Interest rate (%)	4.60%
Gross amount [member] | Hybrid bond 1-1 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond		800,000
Gross amount [member] | Hybrid bond 1-2 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond	₩ 200,000	200,000
Issuance cost [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond	(616)	(3,081)
POSCO ENERGY CO., LTD. [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond	₩ 139,571	498,468
POSCO ENERGY CO., LTD. [member] | Hybrid bond 1-4 [member]
Disclosure of detailed information about borrowings [line items]
Date of issue	Aug. 29, 2013
Date of maturity	Aug. 29, 2043
Interest rate (%)	5.21%
POSCO ENERGY CO., LTD. [member] | Gross amount [member] | Hybrid bond 1-1 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond		165,000
POSCO ENERGY CO., LTD. [member] | Gross amount [member] | Hybrid bond 1-2 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond		165,000
POSCO ENERGY CO., LTD. [member] | Gross amount [member] | Hybrid bond 1-3 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond		30,000
POSCO ENERGY CO., LTD. [member] | Gross amount [member] | Hybrid bond 1-4 [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond	₩ 140,000	140,000
POSCO ENERGY CO., LTD. [member] | Issuance cost [member]
Disclosure of detailed information about borrowings [line items]
Hybrid bond	₩ (429)	₩ (1,532)

Hybrid Bonds - Hybrid Bonds I_2

Hybrid Bonds - Hybrid Bonds Issued by POSCO ENERGY Co., Ltd. (Parenthetical) (Detail) - Hybrid bond 1-4 [member] - POSCO ENERGY CO., LTD. [member]	12 Months Ended
	Dec. 31, 2018
Disclosure of detailed information about borrowings [line items]
Maturity date	30 years (The Company has a right to extend the maturity date)
Interest rate	Issue date ~ 2023-08-29 : 5.21% Reset every 10 years as follows; · After 10 years : return on government bond (10 years) + 1.55% · After 10 years : additionally +0.25% according to Step-up clauses · After 30 years : additionally +0.75%
Interest rate (%)	5.21%
Interest rate adjustment	0.75%
Interest payments condition	Quarterly (Optional deferral of interest payment is available to the issuer)
Others	The issuer can call the hybrid bond at year 10 and interest payment date afterwards
After 10 years : Return on Government Bond [member]
Disclosure of detailed information about borrowings [line items]
Interest rate adjustment	1.55%
After 10 years [member]
Disclosure of detailed information about borrowings [line items]
Interest rate adjustment	0.25%

Reserves - Summary of Reserves

Reserves - Summary of Reserves (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of reserves within equity [abstract]
Accumulated comprehensive loss of investments in associates and joint ventures	₩ (670,435)	₩ (516,528)
Changes in fair value of equity investments at fair value through other comprehensive income	(295,300)
Changes in the unrealized fair value of available-for-saleinvestments	(295,300)	230,190	₩ 276,143
Foreign currency translation differences	(417,817)	(372,166)
Gain or losses on valuation of derivatives	(352)	(136)
Others	(20,464)	(23,916)
Reserves	₩ (1,404,368)	₩ (682,556)

Reserves - Changes in the Unrea

Reserves - Changes in the Unrealized Fair Value of Available-for-sale Investments (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of reserves within equity [abstract]
Changes in unrealized fair value of available-for-sale investments, beginning balance	₩ 230,190	₩ 276,143
Initial application of IFRS No. 9	(421,525)
Changes in unrealized fair value of equity investments	(139,226)	183,761
Reclassification upon disposal	45,737	(299,862)
Impairment of available-for-sale investments		96,083
Others	(10,476)	(25,935)
Changes in unrealized fair value of available-for-sale investments, ending balance	₩ (295,300)	₩ 230,190

Treasury Shares - Changes in Tr

Treasury Shares - Changes in Treasury Shares (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of shares, Beginning	7,187,231	7,189,170
Number of shares, Disposal of treasury shares	(1,528)	(1,939)
Number of shares, Ending	7,185,703	7,187,231	7,189,170
Amount, Beginning	₩ 1,533,054
Amount, Disposal of treasury shares	(459)	₩ (540)	₩ (462)
Amount, Ending	₩ 1,532,728	₩ 1,533,054
Treasury shares [member]
Number of shares, Beginning	7,187,231	7,189,170
Number of shares, Disposal of treasury shares	(1,528)	(1,939)
Number of shares, Ending	7,185,703	7,187,231	7,189,170
Amount, Beginning	₩ 1,533,054	₩ 1,533,468
Amount, Disposal of treasury shares	(326)	(414)	₩ (430)
Amount, Ending	₩ 1,532,728	₩ 1,533,054	₩ 1,533,468

Revenue - Summary of Revenue Di

Revenue - Summary of Revenue Disaggregated by Types of Revenue and Timing of Revenue Recognition (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	₩ 65,154,636	₩ 60,186,867	₩ 52,939,771
Revenue from sales of goods [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	53,974,566	51,357,709	43,545,026
Revenue from services [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	3,533,639	2,064,874	2,414,678
Revenue from construction contract [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	7,133,773	6,299,192	6,497,279
Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	512,658	465,092	482,788
Revenue recognized at a point in time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	54,603,917	51,832,584	44,037,764
Revenue recognized over time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	10,550,719	8,354,283	8,902,007
Steel [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	32,358,009	30,230,368	26,844,155
Steel [member] | Revenue from sales of goods [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	31,733,609	30,064,680	26,687,899
Steel [member] | Revenue from services [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	583,359	111,494	102,657
Steel [member] | Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	41,041	54,194	53,599
Steel [member] | Revenue recognized at a point in time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	31,774,650	30,118,874	26,741,498
Steel [member] | Revenue recognized over time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	583,359	111,494	102,657
Trading [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	22,407,717	20,802,207	16,774,078
Trading [member] | Revenue from sales of goods [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	21,632,183	20,655,267	16,602,482
Trading [member] | Revenue from services [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	611,752	28,793	24,703
Trading [member] | Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	163,782	118,147	146,893
Trading [member] | Revenue recognized at a point in time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	21,795,965	20,773,414	16,749,375
Trading [member] | Revenue recognized over time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	611,752	28,793	24,703
Construction [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	6,946,269	6,418,373	6,624,605
Construction [member] | Revenue from sales of goods [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	3,568	20,368	11,496
Construction [member] | Revenue from services [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	63,922	48,408	50,189
Construction [member] | Revenue from construction contract [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	6,860,995	6,262,038	6,474,192
Construction [member] | Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	17,784	87,559	88,728
Construction [member] | Revenue recognized at a point in time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	127,182	107,927	100,224
Construction [member] | Revenue recognized over time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	6,819,087	6,310,446	6,524,381
Other [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	3,442,641	2,735,919	2,696,933
Other [member] | Revenue from sales of goods [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	605,206	617,394	243,149
Other [member] | Revenue from services [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	2,274,606	1,876,179	2,237,129
Other [member] | Revenue from construction contract [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	272,778	37,154	23,087
Other [member] | Others [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	290,051	205,192	193,568
Other [member] | Revenue recognized at a point in time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	906,120	832,369	446,667
Other [member] | Revenue recognized over time [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	₩ 2,536,521	₩ 1,903,550	₩ 2,250,266

Revenue - Summary of Contract A

Revenue - Summary of Contract Assets and Liabilities From Contracts With Customers (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Jan. 01, 2018
Disclosure of Receivables, customer finance, contract assets and contract liabilities [abstract]
Account receivables	₩ 8,819,617	₩ 8,795,470
Due from customers for contract work	737,712	647,385
Advance received	1,278,731	1,547,247
Due to customers for contract work	641,064	751,933
Unearned revenue	₩ 91,872	₩ 77,657

Revenue - Contract Balances - S

Revenue - Contract Balances - Summary of In-Progress Contracts (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of disaggregation of revenue from contracts with customers [abstract]
Accumulated cost	₩ 26,153,452	₩ 21,404,321
Accumulated contract profit	1,848,718	1,524,208
Accumulated contract loss	(804,538)	(718,593)
Accumulated contract revenue	₩ 27,197,632	₩ 22,209,936

Revenue - Contract Details - Su

Revenue - Contract Details - Summary of Due From Customers for Contract Work and Due to Customers for Contract Work (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of disaggregation of revenue from contracts with customers [abstract]
Unbilled due from customers for contract work	₩ 810,655	₩ 728,007
Due to customers for contract work	(641,064)	(782,968)
Construction contract in progress	₩ 169,591	₩ (54,961)

Revenue - Summary of Changes in

Revenue - Summary of Changes in Estimated Total Contract Costs and Impact on Profit or Loss (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of disaggregation of revenue from contracts with customers [abstract]
Changes in estimated total contract costs	₩ 427,812	₩ 164,812
Changes in profit before income taxes of construction contract :
- Current period	(38,720)	(69,656)
- Future periods	₩ 69,428	₩ (6,041)

Revenue - Summary of Significan

Revenue - Summary of Significant Assumptions Including Uncertainty of Estimate of Total Contract Costs (Detail)	12 Months Ended
	Dec. 31, 2018
Material cost [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Method of significant assumption	Assumption based on recent purchasing price and quoted market price
Labor cost [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Method of significant assumption	Assumption based on standard monthly and daily labor cost
Outsourcing cost [member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Method of significant assumption	Assumption based on the past experience rate of similar project and market price

Selling and Administrative Ex_3

Selling and Administrative Expenses - Summary of Other Administrative Expenses (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of comprehensive income [Line Items]
Wages and salaries	₩ 3,372,831	₩ 3,105,364	₩ 3,016,488
Expenses related to post-employment benefits	216,489	199,926	287,607
Depreciation	2,911,048	2,887,646	2,835,843
Amortization	356,581	409,774	378,004
Electricity expenses	949,435	933,045	1,018,429
Research & development	526,602	486,888	444,798
Vehicles maintenance	1,414,940	1,336,969	1,342,009
Others	1,985,755	2,003,106	2,126,390
Total administrative expenses	1,985,755	2,003,106	2,126,390
Administrative expenses [member]
Statement of comprehensive income [Line Items]
Wages and salaries	813,467	774,900	769,589
Expenses related to post-employment benefits	73,290	78,654	200,956
Other employee benefits	176,240	159,920	176,794
Travel	40,929	39,790	40,828
Depreciation	101,274	97,261	103,442
Amortization	112,418	146,314	139,569
Communication	10,616	11,740	11,186
Electricity expenses	8,309	7,050	7,527
Taxes and public dues	71,973	72,826	78,895
Rental	69,516	69,976	82,005
Repairs	15,291	9,859	11,316
Entertainment	11,816	11,582	13,157
Advertising	106,875	119,724	86,141
Research & development	108,352	125,795	120,608
Service fees	165,938	193,387	201,129
Vehicles maintenance	8,942	8,211	10,090
Industry association fee	9,571	10,140	13,468
Conference	14,510	14,494	13,108
Increase to provisions	14,433	10,990	6,532
Others	₩ 51,995	₩ 40,493	₩ 40,050

Selling and Administrative Ex_4

Selling and Administrative Expenses - Summary of Selling Expenses (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of comprehensive income [Line Items]
Freight and custody expenses	₩ 1,414,940	₩ 1,336,969	₩ 1,342,009
Sales commissions	79,080	115,925	94,377
Total Selling expenses	369,245	1,557,277	1,553,686
Selling expenses [member]
Statement of comprehensive income [Line Items]
Freight and custody expenses	184,675	1,336,969	1,342,009
Operating expenses for distribution center	10,614	10,503	10,315
Sales commissions	79,080	115,925	94,377
Sales advertising	4,821	3,800	5,117
Sales promotion	13,792	12,414	10,670
Sample	2,716	1,989	2,335
Sales insurance premium	37,251	36,546	31,379
Contract cost	16,992	23,061	49,480
Others	₩ 19,304	₩ 16,070	₩ 8,004

Research and Development Expe_3

Research and Development Expenditures Recognized as Expenses - Summary of Research and Development Expenditures Recognized as Expenses (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of comprehensive income [Line Items]
Research and development expenditures recognized as expenses	₩ 526,602	₩ 486,888	₩ 444,798
Administrative expenses [member]
Statement of comprehensive income [Line Items]
Research and development expenditures recognized as expenses	108,352	125,795	120,608
Cost of sales [member]
Statement of comprehensive income [Line Items]
Research and development expenditures recognized as expenses	₩ 418,250	₩ 361,093	₩ 324,190

Other Operating Income and Ex_3

Other Operating Income and Expenses - Details of Other Operating Income and Expenses (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other operating income
Gain on disposals of assets held for sale	₩ 27,171	₩ 1,180	₩ 23,112
Gain on disposals of investment in subsidiaries, associates and joint ventures	45,241	81,794	23,305
Gain on disposals of property, plant and equipment	53,139	32,145	23,826
Gain on disposals of intangible assets	117,139	23,391	671
Gain on valuation of firm commitment	39,028	56,301
Gain on insurance proceeds	14,034	5,878	22,400
Others	227,834	247,792	109,164
Other operating income	523,586	448,481	202,478
Other operating expenses
Impairment loss on assets held for sale	(50,829)		(24,890)
Loss on disposals of investments in subsidiaries, associates and joint ventures	(5,226)	(19,985)	(22,499)
Loss on disposals of property, plant and equipment	(117,614)	(151,343)	(86,622)
Impairment loss on property, plant and equipment	(1,004,704)	(117,231)	(196,882)
Impairment loss on investment property	(51,461)	0	(318)
Loss on disposals of investment property	(9,154)	(1,966)	(21)
Impairment loss on intangible assets	(337,519)	(167,995)	(127,875)
Increase to provisions	(134,632)	(33,964)	(53,058)
Loss on valuation of firm commitment	(66,281)	(43,164)
Donations	(52,074)	(51,424)	(43,810)
Idle tangible asset expenses	(9,257)	(10,490)	(6,437)
Others	(175,711)	(93,814)	(143,083)
Other operating expenses	₩ (2,014,462)	₩ (691,376)	₩ (705,495)

Other Operating Income and Ex_4

Other Operating Income and Expenses - Details of Other Operating Income and Expenses (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Analysis of income and expense [abstract]
Tax refund upon successful appeal to tax	₩ 55,306
Refund of VAT and other taxes		₩ 160,501
Additional taxes imposed about value added tax	₩ 52,997

Finance Income and Costs - Deta

Finance Income and Costs - Details of Finance Income and Costs (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finance income
Interest income	₩ 337,258	₩ 212,451	₩ 182,475
Dividend income	63,345	92,962	41,000
Gain on foreign currency transactions	716,060	785,616	1,032,552
Gain on foreign currency translations	212,443	564,016	377,723
Gain on derivatives transactions	247,513	210,727	316,524
Gain on valuations of derivatives	96,986	64,735	147,111
Gain on disposals of available-for-sale financial assets		425,684	130,830
Gain on valuations of financial assets at fair value through profit or loss	16,149
Others	16,216	16,476	3,765
Finance income	1,705,970	2,372,667	2,231,980
Finance costs
Interest expenses	(741,296)	(653,115)	(658,726)
Loss on foreign currency transactions	(810,857)	(756,654)	(1,147,192)
Loss on foreign currency translations	(321,748)	(422,880)	(405,391)
Loss on derivatives transactions	(208,772)	(236,273)	(338,314)
Loss on valuation of derivatives	(40,674)	(226,487)	(162,676)
Impairment loss on available-for-sale financial assets		(123,214)	(248,404)
Loss on valuations of financial assets at fair value through profit or loss	(59,442)
Others	(61,627)	(65,654)	(53,487)
Finance costs	₩ (2,244,416)	₩ (2,484,277)	₩ (3,014,190)

Finance Income and Costs - De_2

Finance Income and Costs - Details of Finance Income and Costs (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Analysis of income and expense [abstract]
Interest income	₩ 197,142	₩ 130,710	₩ 106,828

Expenses by Nature - Summary of

Expenses by Nature - Summary of Expenses by Nature (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Analysis of income and expense [abstract]
Raw material used, changes in inventories and others	₩ 38,884,690	₩ 35,584,184	₩ 30,177,732
Employee benefits expenses	3,639,192	3,357,861	3,444,276
Outsourced processing cost	7,462,656	7,074,948	7,678,055
Electricity expenses	949,435	933,045	1,018,429
Depreciation	2,911,048	2,887,646	2,835,843
Amortization	356,581	409,774	378,004
Freight and custody expenses	1,414,940	1,336,969	1,342,009
Sales commissions	79,080	115,925	94,377
Loss on disposal of property, plant and equipment	117,614	151,343	86,622
Impairment loss on property, plant and equipment	1,004,704	117,231	196,882
Impairment loss on goodwill and intangible assets	337,519	167,995	127,875
Donations	52,074	51,424	43,810
Other expenses	4,445,124	4,253,625	3,448,497
Expenses by nature	61,654,657	56,441,970	50,872,411
Wages and salaries	3,372,831	3,105,364	3,016,488
Expenses related to post-employment benefits	266,361	252,497	427,788
Employee benefits expenses	₩ 3,639,192	₩ 3,357,861	₩ 3,444,276

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Expense (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Major components of tax expense (income) [abstract]
Current income taxes	₩ 1,577,581	₩ 864,143	₩ 699,269
Deferred income tax due to temporary differences	(38,851)	300,037	(209,706)
Items recorded directly in equity	144,900	21,560	(110,019)
Income tax expense	₩ 1,683,630	₩ 1,185,740	₩ 379,544

Income Taxes - Income Tax Credi

Income Taxes - Income Tax Credit (Charged) Directly to Equity (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current and deferred tax relating to items charged or credited directly to equity [abstract]
Net changes in fair value of equity investments at fair value through other comprehensive income	₩ 47,423	₩ 1,271	₩ (100,550)
Remeasurements of defined benefit plans	56,289	22,208	(11,722)
Gain on sale of treasury shares	(50)	(40)	(10)
Others	41,238	(1,879)	2,263
Income taxes credited (charged) directly to equity	₩ 144,900	₩ 21,560	₩ (110,019)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Major components of tax expense (income) [abstract]
POSCO's statutory rate	27.50%	27.50%	27.50%
Deductible temporary differences	₩ 5,590,698
Taxable temporary differences, not recognized	₩ 4,873,232

Income Taxes - Reconciliation O

Income Taxes - Reconciliation Of Calculated Income Tax Expense Based on the Statutory Rate to Actual Amount of Taxes Recorded (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of accounting profit multiplied by applicable tax rates [abstract]
Profit before income tax expense	₩ 3,616,016	₩ 4,095,051	₩ 1,411,609
Income tax expense computed at statutory rate	982,287	990,540	341,148
Adjustments:
Tax credits	(32,103)	(40,757)	(30,124)
Additional Income tax expense for prior years (Over provisions from prior years)	44,336	(20,912)	(11,829)
Tax effect from tax audit	130,196
Investment in subsidiaries, associates and joint ventures	114,856	55,113	76,751
Tax effects due to permanent differences	64,708	4,798	(9,962)
Effect of tax rate change		175,647
Others	379,350	21,311	13,560
Adjustments	701,343	195,200	38,396
Income tax expense	₩ 1,683,630	₩ 1,185,740	₩ 379,544
Effective tax rate	46.56%	28.96%	26.89%

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation Of Calculated Income Tax Expense Based on the Statutory Rate to Actual Amount of Taxes Recorded (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Income Taxes [Line Items]
Statutory rate	27.50%	27.50%	27.50%
Changes in tax rates or tax laws enacted or announced [member]
Disclosure of Income Taxes [Line Items]
Statutory rate	27.50%
Excess of taxable income enacted	₩ 300,000

Income Taxes - Movements in Def

Income Taxes - Movements in Deferred Tax Assets (Liabilities) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	₩ (441,187)	₩ (142,720)
Inc. (Dec.)	161,081	(298,467)
Ending	(280,106)	(441,187)
Allowance for credit losses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	273,994	213,119
Inc. (Dec.)	(92,851)	60,875
Ending	181,143	273,994
Reserve for technology developments [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(37,987)	(91,960)
Inc. (Dec.)	37,987	53,973
Ending		(37,987)
Property, plant and equipment depreciation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	14,641	(11,639)
Inc. (Dec.)	(4,804)	26,280
Ending	9,837	14,641
Share of profit or loss of equity-accounted investees [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	196,042	70,259
Inc. (Dec.)	31,552	125,783
Ending	227,594	196,042
Allowance for inventories valuation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	10,780	15,651
Inc. (Dec.)	(104)	(4,871)
Ending	10,676	10,780
Property, plant and equipment revaluation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(1,828,164)	(1,524,149)
Inc. (Dec.)	(33,548)	(304,015)
Ending	(1,861,712)	(1,828,164)
Prepaid expenses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	20,000	19,665
Inc. (Dec.)	(2,741)	335
Ending	17,259	20,000
Property, plant and equipment impairment loss [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	5,540	5,295
Inc. (Dec.)	(927)	245
Ending	4,613	5,540
Gain or loss on foreign currency [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(48,472)	(5,957)
Inc. (Dec.)	10,462	(42,515)
Ending	(38,010)	(48,472)
Defined benefit obligations [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	430,117	361,838
Inc. (Dec.)	70,334	68,279
Ending	500,451	430,117
Plan assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(397,621)	(355,661)
Inc. (Dec.)	(66,940)	(41,960)
Ending	(464,561)	(397,621)
Provision for construction losses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	441	997
Inc. (Dec.)	6,964	(556)
Ending	7,405	441
Provision for construction warranty [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	28,717	24,322
Inc. (Dec.)	41,601	4,395
Ending	70,318	28,717
Accrued income [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(12,915)	(9,441)
Inc. (Dec.)	(179)	(3,474)
Ending	(13,094)	(12,915)
Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	694,317	750,151
Inc. (Dec.)	(233,026)	(55,834)
Ending	461,291	694,317
Temporary differences [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(650,570)	(537,510)
Inc. (Dec.)	(236,220)	(113,060)
Ending	(886,790)	(650,570)
Changes in fair value of investments in equity instruments measured at fair value through other comprehensive income [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	(49,236)	(50,507)
Inc. (Dec.)	206,121	1,271
Ending	156,885	(49,236)
Other deferred income taxes recognized directly to equity [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	72,161	51,832
Inc. (Dec.)	58,111	20,329
Ending	130,272	72,161
Deferred income taxes recognized directly to equity [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	22,925	1,325
Inc. (Dec.)	264,232	21,600
Ending	287,157	22,925
Tax credit carryforward and others [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	118,032	307,335
Inc. (Dec.)	(2,443)	(189,303)
Ending	115,589	118,032
Investments in subsidiaries, associates and joint ventures [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning	68,426	86,130
Inc. (Dec.)	135,512	(17,704)
Ending	₩ 203,938	₩ 68,426

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets And Liabilities (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	₩ 3,170,473	₩ 2,811,648
Liabilities	(3,450,579)	(3,252,835)
Net	(280,106)	(441,187)	₩ (142,720)
Allowance for credit losses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	181,143	273,994
Net	181,143	273,994	213,119
Reserve for technology developments [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Liabilities		(37,987)
Net		(37,987)	(91,960)
Property, plant and equipment depreciation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	55,354	59,912
Liabilities	(45,517)	(45,271)
Net	9,837	14,641	(11,639)
Share of profit or loss of equity-accounted investees [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	278,466	236,637
Liabilities	(50,872)	(40,595)
Net	227,594	196,042	70,259
Allowance for inventories valuation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	10,676	10,780
Net	10,676	10,780	15,651
Property, plant and equipment revaluation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Liabilities	(1,861,712)	(1,828,164)
Net	(1,861,712)	(1,828,164)	(1,524,149)
Prepaid expenses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	17,259	20,000
Net	17,259	20,000	19,665
Property, plant and equipment impairment loss [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	5,240	5,639
Liabilities	(627)	(99)
Net	4,613	5,540	5,295
Gain or loss on foreign currency [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	121,797	113,760
Liabilities	(159,807)	(162,232)
Net	(38,010)	(48,472)	(5,957)
Defined benefit obligations [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	500,451	430,117
Net	500,451	430,117	361,838
Plan assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Liabilities	(464,561)	(397,621)
Net	(464,561)	(397,621)	(355,661)
Provision for construction losses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	7,405	441
Net	7,405	441	997
Provision for construction warranty [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	70,318	28,717
Net	70,318	28,717	24,322
Accrued income [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Liabilities	(13,094)	(12,915)
Net	(13,094)	(12,915)	(9,441)
Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	857,583	746,367
Liabilities	(396,292)	(52,050)
Net	461,291	694,317	750,151
Temporary differences [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	2,105,692	1,926,364
Liabilities	(2,992,482)	(2,576,934)
Net	(886,790)	(650,570)	(537,510)
Changes in fair value of investments in equity instruments measured at fair value through other comprehensive income [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	247,921	110,865
Liabilities	(91,036)	(160,101)
Net	156,885	(49,236)	(50,507)
Other deferred income taxes recognized directly to equity [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	153,609	92,981
Liabilities	(23,337)	(20,820)
Net	130,272	72,161	51,832
Deferred income taxes recognized directly to equity [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	401,530	203,846
Liabilities	(114,373)	(180,921)
Net	287,157	22,925	1,325
Tax credit carryforward and others [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	115,589	118,032
Net	115,589	118,032	307,335
Investments in subsidiaries, associates and joint ventures [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Assets	547,662	563,406
Liabilities	(343,724)	(494,980)
Net	₩ 203,938	₩ 68,426	₩ 86,130

Earnings Per Share - Basic And

Earnings Per Share - Basic And Diluted Earnings Per Share (Detail) - KRW (₩)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings per share [abstract]
Profit attribute to controlling interest	₩ 1,711,902,000,000	₩ 2,756,230,000,000	₩ 1,354,807,000,000
Interests of hybrid bonds	₩ (17,720,986,299)	₩ (33,048,799,997)	₩ (33,225,163,081)
Weighted-average number of common shares outstanding	80,000,606	79,998,600	79,996,389
Basic and diluted earnings per share	₩ 21,177	₩ 34,040	₩ 16,521
Total number of common shares issued	87,186,835	87,186,835	87,186,835
Weighted-average number of treasury shares	(7,186,229)	(7,188,235)	(7,190,446)
Weighted-average number of common shares outstanding	80,000,606	79,998,600	79,996,389

Related Party Transactions - Si

Related Party Transactions - Significant Transactions Between the Controlling Company and Related Parties (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of transactions between related parties [line items]
Sales		₩ 12,751,894
Other sales		153,870
Purchase of material		3,913,323
Purchase of fixed assets		829,730
Outsourced processing cost		650,170
Others		428,940
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Sales		3,328
Other sales		71
Purchase of fixed assets		151,639
Outsourced processing cost		32
Others		18,352
POSCO Processing & Service [member]
Disclosure of transactions between related parties [line items]
Sales		298,781
Other sales		1
Purchase of material		113,628
Purchase of fixed assets		4,595
Outsourced processing cost		8,309
Others		404
POSCO COATED & COLOR STEEL Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		417,369
Other sales		3,533
Outsourced processing cost		8,483
Others		106
POSCO ICT [member]
Disclosure of transactions between related parties [line items]
Sales		1,697
Other sales		5,097
Purchase of fixed assets		315,748
Outsourced processing cost		29,773
Others		183,226
eNtoB Corporation [member]
Disclosure of transactions between related parties [line items]
Sales		1
Other sales		30
Purchase of material		330,921
Purchase of fixed assets		8,215
Outsourced processing cost		139
Others		26,023
POSCO CHEMTECH [member]
Disclosure of transactions between related parties [line items]
Sales		359,862
Other sales		33,076
Purchase of material		479,896
Purchase of fixed assets		23,043
Outsourced processing cost		296,296
Others		6,860
POSCO ENERGY CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Sales		179,966
Other sales		1,456
Others		2
POSCO DAEWOO Corporation [member]
Disclosure of transactions between related parties [line items]
Sales		5,214,127
Other sales		35,182
Purchase of material		550,258
Purchase of fixed assets		221
Outsourced processing cost		44,108
Others		1,948
POSCO Thainox Public Company Limited [member]
Disclosure of transactions between related parties [line items]
Sales		218,005
Other sales		9,780
Purchase of material		10,168
POSCO America Corporation [member]
Disclosure of transactions between related parties [line items]
Sales		345,225
Purchase of material		90
Others		1,776
POSCO Canada Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		439
Other sales		690
Purchase of material		278,915
POSCO Asia Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		1,949,354
Other sales		1,454
Purchase of material		365,025
Purchase of fixed assets		337
Outsourced processing cost		1,625
Others		4,982
Qingdao Pohang Stainless Steel Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		161,803
Others		176
POSCO JAPAN Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		1,436,159
Other sales		20
Purchase of material		26,256
Purchase of fixed assets		621
Others		44,829
POSCO-VIETNAM Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		212,883
Others		7
POSCO MEXICO S.A. DE C.V. [member]
Disclosure of transactions between related parties [line items]
Sales		276,387
Others		1,749
POSCO Maharashtra Steel Private Limited [member]
Disclosure of transactions between related parties [line items]
Sales		467,206
Others		65
POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		192,467
Others [member]
Disclosure of transactions between related parties [line items]
Sales		932,048
Other sales		10,073
Purchase of material		262,828
Purchase of fixed assets		25,270
Outsourced processing cost		240,687
Others		118,665
Subsidiaries [member]
Disclosure of transactions between related parties [line items]
Sales		12,667,107
Other sales		100,463
Purchase of material		2,417,985
Purchase of fixed assets		529,689
Outsourced processing cost		629,452
Others		409,170
POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		2,947
Other sales		112
Purchase of material		5,487
Purchase of fixed assets		300,041
Outsourced processing cost		20,718
Others		19,763
SNNC [member]
Disclosure of transactions between related parties [line items]
Sales		6,734
Other sales		712
Purchase of material		554,151
Others		4
POSCO-SAMSUNG-Slovakia Processing Center [member]
Disclosure of transactions between related parties [line items]
Sales		52,779
Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales		14,943
Other sales		52,583
Purchase of material		79,103
Others		3
Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales		84,787
Other sales		53,407
Purchase of material		1,495,338
Purchase of fixed assets		300,041
Outsourced processing cost		20,718
Others		19,770
Roy Hill Holdings Pty Ltd. [member]
Disclosure of transactions between related parties [line items]
Purchase of material		697,096
CSP - Compania Siderurgica do Pecem [member]
Disclosure of transactions between related parties [line items]
Sales		7,384
Purchase of material		₩ 159,501
Posco [member]
Disclosure of transactions between related parties [line items]
Sales	₩ 13,564,308		₩ 11,239,938
Other sales	202,162		169,401
Purchase of material	4,367,687		2,882,146
Purchase of fixed assets	965,298		741,739
Outsourced processing cost	712,217		610,018
Others	438,631		388,292
Posco [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Sales	7,827		29,511
Other sales	97		16,661
Purchase of material			8
Purchase of fixed assets	322,924		183,768
Outsourced processing cost	47
Others	36,428		24,511
Posco [member] | POSCO Processing & Service [member]
Disclosure of transactions between related parties [line items]
Sales			1,212,220
Other sales			5,778
Purchase of material			549,803
Purchase of fixed assets			2,896
Outsourced processing cost			22,704
Others			2,445
Posco [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	476,105		326,078
Other sales	2,725		2,560
Outsourced processing cost	9,211		12,232
Others	1,434		126
Posco [member] | POSCO ICT [member]
Disclosure of transactions between related parties [line items]
Sales	2,624		1,224
Other sales	7,479		727
Purchase of fixed assets	341,472		219,301
Outsourced processing cost	34,376		32,456
Others	196,252		171,107
Posco [member] | eNtoB Corporation [member]
Disclosure of transactions between related parties [line items]
Sales	12
Other sales	60		5
Purchase of material	377,198		278,016
Purchase of fixed assets	27,508		9,836
Outsourced processing cost	390		212
Others	31,455		19,436
Posco [member] | POSCO CHEMTECH [member]
Disclosure of transactions between related parties [line items]
Sales	417,957		319,164
Other sales	35,762		33,784
Purchase of material	531,452		502,448
Purchase of fixed assets	21,730		14,847
Outsourced processing cost	319,868		290,427
Others	2,802		5,139
Posco [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Sales	206,638		187,311
Other sales	1,445		1,382
Others			7
Posco [member] | POSCO TMC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			219,489
Purchase of material			2
Outsourced processing cost			863
Others			1,177
Posco [member] | POSCO AST [member]
Disclosure of transactions between related parties [line items]
Sales			152,098
Other sales			1
Outsourced processing cost			19,695
Others			922
Posco [member] | POSCO DAEWOO Corporation [member]
Disclosure of transactions between related parties [line items]
Sales	5,835,226		3,227,716
Other sales	42,888		34,341
Purchase of material	690,345		92,203
Outsourced processing cost	57,624		343
Others	4,318
Posco [member] | POSCO Thainox Public Company Limited [member]
Disclosure of transactions between related parties [line items]
Sales	299,450		237,471
Other sales	5,335		2,915
Purchase of material	10,115		9,593
Outsourced processing cost			19
Others	71		548
Posco [member] | POSCO America Corporation [member]
Disclosure of transactions between related parties [line items]
Sales	336,366		469,543
Purchase of material			284
Others	2,486		1,103
Posco [member] | POSCO Canada Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			275
Other sales	2,155
Purchase of material	300,982		148,528
Posco [member] | POSCO Asia Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	1,857,665		1,758,080
Other sales	253		1,373
Purchase of material	536,280		403,174
Purchase of fixed assets	650		247
Outsourced processing cost	2,449		939
Others	6,524		3,602
Posco [member] | Qingdao Pohang Stainless Steel Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	188,252		135,405
Other sales	7
Others	34		525
Posco [member] | POSCO JAPAN Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	1,353,313		1,112,489
Other sales	6		128
Purchase of material	25,773		23,217
Purchase of fixed assets	4,204		3,744
Outsourced processing cost			345
Others	5,411		3,841
Posco [member] | POSCO-VIETNAM Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	273,573		226,063
Other sales	156		445
Others	8
Posco [member] | POSCO MEXICO S.A. DE C.V. [member]
Disclosure of transactions between related parties [line items]
Sales	299,276		274,210
Other sales	17		462
Others	35
Posco [member] | POSCO Maharashtra Steel Private Limited [member]
Disclosure of transactions between related parties [line items]
Sales	563,618		355,829
Other sales	584		2,613
Others	156		93
Posco [member] | POSCO(Suzhou) Automotive Processing Center Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	196,095		149,911
Purchase of material	2,616
Others	5
Posco [member] | Others [member]
Disclosure of transactions between related parties [line items]
Sales	1,158,122		766,263
Other sales	44,098		22,717
Purchase of material	456,804		207,601
Purchase of fixed assets	31,787		62,202
Outsourced processing cost	264,060		212,344
Others	140,869		145,562
Posco [member] | Subsidiaries [member]
Disclosure of transactions between related parties [line items]
Sales	13,472,119		11,160,350
Other sales	143,067		125,892
Purchase of material	2,931,565		2,214,877
Purchase of fixed assets	750,275		496,841
Outsourced processing cost	688,025		592,579
Others	428,288		380,144
Posco [member] | SeAH Changwon Integrated Special Steel [member]
Disclosure of transactions between related parties [line items]
Sales			28
Purchase of material			1,095
Outsourced processing cost			627
Posco [member] | POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	10,904		2,245
Other sales	240		48
Purchase of material	3,166		3,533
Purchase of fixed assets	215,023		244,898
Outsourced processing cost	24,192		16,812
Others	10,257		8,146
Posco [member] | SNNC [member]
Disclosure of transactions between related parties [line items]
Sales	5,105		6,004
Other sales	4,108		1,042
Purchase of material	558,425		487,395
Others	80		2
Posco [member] | POSCO-SAMSUNG-Slovakia Processing Center [member]
Disclosure of transactions between related parties [line items]
Sales	61,981		44,686
Posco [member] | KOBRASCO [member]
Disclosure of transactions between related parties [line items]
Other sales			29,297
Posco [member] | Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales	14,199		26,625
Other sales	54,747		13,122
Purchase of material	64,335		175,246
Others	6
Posco [member] | Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales	92,189		79,588
Other sales	59,095		43,509
Purchase of material	1,436,122		667,269
Purchase of fixed assets	215,023		244,898
Outsourced processing cost	24,192		17,439
Others	10,343		₩ 8,148
Posco [member] | Roy Hill Holdings Pty Ltd. [member]
Disclosure of transactions between related parties [line items]
Purchase of material	₩ 810,196

Related Party Transactions - _2

Related Party Transactions - Significant Transactions Between the Controlling Company and Related Parties (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of transactions between related parties [line items]
Loans to related parties during the year	₩ 627,783	₩ 1,055,895	₩ 603,332
Loans recorded as allowance for doubtful accounts	916,790	1,094,464	₩ 977,771	₩ 999,678
Posco [member] | Suncheon Eco Trans Co., Ltd [member]
Disclosure of transactions between related parties [line items]
Loans to related parties during the year	2,950
Loans [member]
Disclosure of transactions between related parties [line items]
Loans recorded as allowance for doubtful accounts	147,980	₩ 258,957
Loans [member] | Posco [member] | Suncheon Eco Trans Co., Ltd [member]
Disclosure of transactions between related parties [line items]
Loans recorded as allowance for doubtful accounts	₩ 2,950

Related Party Transactions - Re

Related Party Transactions - Related Account Balances of Significant Transactions Between the Controlling Company and Related Parties (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	₩ 122,670
Accounts payable	320,200
Other payables	121,846
Total payables	564,716
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Accounts payable	52,775
Other payables	438
Total payables	53,213
POSCO COATED & COLOR STEEL Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Accounts payable	25
Other payables	1,194
Total payables	1,219
POSCO ICT [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	1,572
Accounts payable	112,960
Other payables	8,717
Total payables	123,249
eNtoB Corporation [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	10,860
Accounts payable	22,072
Other payables	11
Total payables	32,943
POSCO CHEMTECH [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	19,911
Accounts payable	58,725
Other payables	19,012
Total payables	97,648
POSCO ENERGY CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Other payables	1,425
Total payables	1,425
POSCO DAEWOO Corporation [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	161
Accounts payable	1,881
Other payables	5,304
Total payables	7,346
POSCO Thainox Public Company Limited [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	467
Accounts payable	71
Total payables	538
POSCO America Corporation [member]
Disclosure of transactions between related parties [line items]
Accounts payable	221
Total payables	221
POSCO Asia Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	7,839
Total payables	7,839
Others [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	33,183
Accounts payable	36,591
Other payables	85,745
Total payables	155,519
Subsidiaries [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	73,993
Accounts payable	285,321
Other payables	121,846
Total payables	481,160
POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	3,275
Accounts payable	34,803
Total payables	38,078
SNNC [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	22,188
Total payables	22,188
Roy Hill Holdings Pty Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	22,997
Total payables	22,997
Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	217
Accounts payable	76
Total payables	293
Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	48,677
Accounts payable	34,879
Total payables	83,556
Posco [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	2,046,649	₩ 1,980,600
Other receivables	70,447	78,631
Total receivables	2,117,096	2,059,231
Trade accounts and notes payable		155,922
Accounts payable		224,238
Other payables		84,112
Total payables		464,272
Posco [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	57	2
Other receivables	5,181	2,908
Total receivables	5,238	2,910
Accounts payable		21,965
Other payables		674
Total payables		22,639
Posco [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	55,598	58,184
Other receivables	317	324
Total receivables	55,915	58,508
Accounts payable		5
Other payables		504
Total payables		509
Posco [member] | POSCO ICT [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable		55
Other receivables	229	217
Total receivables	229	272
Trade accounts and notes payable		1,458
Accounts payable		72,586
Other payables		27,009
Total payables		101,053
Posco [member] | eNtoB Corporation [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable		12,252
Accounts payable		31,899
Other payables		20
Total payables		44,171
Posco [member] | POSCO CHEMTECH [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	40,258	61,810
Other receivables	3,883	3,589
Total receivables	44,141	65,399
Trade accounts and notes payable		51,774
Accounts payable		20,313
Other payables		17,568
Total payables		89,655
Posco [member] | POSCO ENERGY CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	22,163	33,239
Other receivables	1,700	1,673
Total receivables	23,863	34,912
Other payables		1,425
Total payables		1,425
Posco [member] | POSCO DAEWOO Corporation [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	437,554	483,915
Other receivables	1,056	12,739
Total receivables	438,610	496,654
Trade accounts and notes payable		10,213
Accounts payable		2,145
Other payables		5,794
Total payables		18,152
Posco [member] | POSCO Thainox Public Company Limited [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	71,189	57,826
Total receivables	71,189	57,826
Trade accounts and notes payable		1,204
Total payables		1,204
Posco [member] | POSCO America Corporation [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	14,338	5,365
Total receivables	14,338	5,365
Posco [member] | POSCO Asia Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	480,205	404,857
Other receivables	1,047	541
Total receivables	481,252	405,398
Trade accounts and notes payable		9,811
Accounts payable		24
Total payables		9,835
Posco [member] | Qingdao Pohang Stainless Steel Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	52,037	31,693
Total receivables	52,037	31,693
Posco [member] | POSCO MEXICO S.A. DE C.V. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	101,179	55,695
Other receivables	218	530
Total receivables	101,397	56,225
Posco [member] | POSCO Maharashtra Steel Private Limited [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	390,413	392,630
Other receivables	1,428	5,733
Total receivables	391,841	398,363
Posco [member] | Others [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	379,950	384,385
Other receivables	54,407	49,403
Total receivables	434,357	433,788
Trade accounts and notes payable		15,038
Accounts payable		59,575
Other payables		31,118
Total payables		105,731
Posco [member] | Subsidiaries [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	2,044,941	1,969,656
Other receivables	69,466	77,657
Total receivables	2,114,407	2,047,313
Trade accounts and notes payable		101,750
Accounts payable		208,512
Other payables		84,112
Total payables		394,374
Posco [member] | POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	249	1,946
Other receivables	10	9
Total receivables	259	1,955
Trade accounts and notes payable		3,842
Accounts payable		15,723
Total payables		19,565
Posco [member] | SNNC [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	541	648
Other receivables	61	61
Total receivables	602	709
Trade accounts and notes payable		49,506
Accounts payable		3
Total payables		49,509
Posco [member] | Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	918	8,350
Other receivables	910	904
Total receivables	1,828	9,254
Trade accounts and notes payable		824
Total payables		824
Posco [member] | Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	1,708	10,944
Other receivables	981	974
Total receivables	₩ 2,689	11,918
Trade accounts and notes payable		54,172
Accounts payable		15,726
Total payables		₩ 69,898

Related Party Transactions - _3

Related Party Transactions - Significant Transactions Between the Company, Excluding the Controlling Company, and Related Companies (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of transactions between related parties [line items]
Sales		₩ 12,751,894
Other sales		153,870
Purchase of material		3,913,323
Other purchases		428,940
POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		2,947
Other sales		112
Purchase of material		5,487
Other purchases		19,763
SNNC [member]
Disclosure of transactions between related parties [line items]
Sales		6,734
Other sales		712
Purchase of material		554,151
Other purchases		4
Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales		14,943
Other sales		52,583
Purchase of material		79,103
Other purchases		3
Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales		84,787
Other sales		53,407
Purchase of material		1,495,338
Other purchases		19,770
Company, excluding the controlling company [member] | POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	₩ 19,394	19,513	₩ 21,659
Other sales			5
Purchase of material	83	98	3,335
Other purchases	24,103	8,113	5,912
Company, excluding the controlling company [member] | New Songdo International City Development, LLC [member]
Disclosure of transactions between related parties [line items]
Sales	30,997	223,567	226,042
Other sales	53,316	13,207
Other purchases	97	49	14
Company, excluding the controlling company [member] | SNNC [member]
Disclosure of transactions between related parties [line items]
Sales	66,075	26,288	29,330
Other sales	128
Purchase of material	2,395	3,578	21,479
Other purchases	71,421	17,985	9,494
Company, excluding the controlling company [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	25,693	42,147	288,307
Company, excluding the controlling company [member] | Noeul Green Energy [member]
Disclosure of transactions between related parties [line items]
Sales	6,444	11,863	107,268
Other purchases	587	2,178
Company, excluding the controlling company [member] | VSC POSCO Steel Corporation [member]
Disclosure of transactions between related parties [line items]
Sales	12,504	19,404	43,650
Other sales			47
Purchase of material	2,314	188	479
Company, excluding the controlling company [member] | USS-POSCO Industries [member]
Disclosure of transactions between related parties [line items]
Sales		26,899	287,072
Other sales		107
Purchase of material	2,595	2,222	1,195
Company, excluding the controlling company [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of transactions between related parties [line items]
Sales	239,922	241,299	157,814
Other sales	9,678
Purchase of material	346,602	101,018
Other purchases	26,324	21,154
Company, excluding the controlling company [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of transactions between related parties [line items]
Sales	46,538	38,484	61,844
Purchase of material	62,851	47,241	57,179
Company, excluding the controlling company [member] | LLP POSUK Titanium [member]
Disclosure of transactions between related parties [line items]
Purchase of material	944	3,972	14,575
Company, excluding the controlling company [member] | BX STEEL POSCO Cold Rolled Sheet Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales		4
Purchase of material	10,572	20,145	24,365
Company, excluding the controlling company [member] | POS-SEAH STEEL WIRE (TIANJIN) CO., Ltd [member]
Disclosure of transactions between related parties [line items]
Sales	12,244	20,004	15,759
Company, excluding the controlling company [member] | PT. batutua tembaga raya [member]
Disclosure of transactions between related parties [line items]
Other sales	168
Purchase of material	15,663	21,024	13,079
Company, excluding the controlling company [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales	30,417	34,088	31,711
Purchase of material	249	192	65
Company, excluding the controlling company [member] | Zhangjiagang Pohang Refractories Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			250
Other sales			14
Purchase of material		87	364
Other purchases		1,632	2,472
Company, excluding the controlling company [member] | Sebang Steel [member]
Disclosure of transactions between related parties [line items]
Sales		441
Purchase of material	13,571	23,778	26,276
Company, excluding the controlling company [member] | SHANGHAI WAIGAOQIAO FREE TRADE ZONE LANSHENG DAEWOO IN'L TRADING CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Sales		43,764	157,886
Purchase of material			3,535
Company, excluding the controlling company [member] | DMSA/AMSA [member]
Disclosure of transactions between related parties [line items]
Other sales		99
Purchase of material	46,293	47,092	72,582
Company, excluding the controlling company [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of transactions between related parties [line items]
Other sales	50,789	62,423	87,973
Company, excluding the controlling company [member] | Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales	359,124	272,107	195,139
Other sales	62,375	43,126	11,184
Purchase of material	19,192	19,520	16,664
Other purchases	50,918	19,483	1,801
Company, excluding the controlling company [member] | Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Sales	849,352	1,019,872	1,746,453
Other sales	176,454	118,962	99,223
Purchase of material	523,324	290,155	277,201
Other purchases	₩ 173,450	₩ 70,594	35,912
Company, excluding the controlling company [member] | SeAH Changwon Integrated Special Steel [member]
Disclosure of transactions between related parties [line items]
Sales			16,294
Purchase of material			22,029
Company, excluding the controlling company [member] | Posco e&c Songdo International Building [member]
Disclosure of transactions between related parties [line items]
Sales			4,245
Other purchases			16,219
Company, excluding the controlling company [member] | Incheon-Gimpo Expressway Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Sales			₩ 102,183

Related Party Transactions - _4

Related Party Transactions - Related Account Balances of Significant Transactions Between the Company, Excluding the Controlling Company, and Related Parties (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	₩ 122,670
Other payables	121,846
Total payables	564,716
POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	3,275
Total payables	38,078
Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	217
Total payables	293
Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes payable	48,677
Total payables	83,556
Company, excluding the controlling company [member] | POSCO PLANTEC Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	3,593	₩ 2,287
Other receivables	6	5
Total receivables	3,599	2,292
Trade accounts and notes payable	6,160	3,442
Other payables	217	5,595
Total payables	6,377	9,037
Company, excluding the controlling company [member] | New Songdo International City Development, LLC [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	233,157	484,038
Loan		282,775
Other receivables		1,696
Total receivables	233,157	768,509
Other payables		7,146
Total payables		7,146
Company, excluding the controlling company [member] | Chuncheon Energy Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Other receivables		21
Total receivables		21
Other payables	1,758	9,617
Total payables	1,758	9,617
Company, excluding the controlling company [member] | Nickel mining company SAS [member]
Disclosure of transactions between related parties [line items]
Loan	59,664	59,668	₩ 60,425
Other receivables	118	118
Total receivables	59,782	59,786
Company, excluding the controlling company [member] | CSP - Compania Siderurgica do Pecem [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	364,190	380,180
Other receivables	9,669	13,443
Total receivables	373,859	393,623
Trade accounts and notes payable	62,578
Other payables		29,700
Total payables	62,578	29,700
Company, excluding the controlling company [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	10,836	2,108
Loan		5,357	6,647
Other receivables		6
Total receivables	10,836	7,471
Trade accounts and notes payable	2,101	2,449
Total payables	2,101	2,449
Company, excluding the controlling company [member] | PT. batutua tembaga raya [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable		24
Loan	35,100	29,048	38,120
Other receivables	171
Total receivables	35,271	29,072
Company, excluding the controlling company [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	6,274	8,067
Loan	3,354	5,357	8,460
Other receivables	27	32
Total receivables	9,655	13,456
Trade accounts and notes payable	66	107
Total payables	66	107
Company, excluding the controlling company [member] | DMSA/AMSA [member]
Disclosure of transactions between related parties [line items]
Loan	64,297	69,713	90,638
Other receivables		4,443
Total receivables	64,297	74,156
Company, excluding the controlling company [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of transactions between related parties [line items]
Loan	191,107	229,880	276,605
Total receivables	191,107	229,880
Company, excluding the controlling company [member] | Other associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	75,382	135,128
Loan	136,117	134,506
Other receivables	13,071	6,889
Total receivables	224,570	276,523
Trade accounts and notes payable	7,768	1,873
Other payables	5,363	2,531
Total payables	13,131	4,404
Company, excluding the controlling company [member] | Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	707,135	1,011,832
Loan	489,639	816,304	₩ 684,132
Other receivables	23,062	26,653
Total receivables	1,219,836	1,854,789
Trade accounts and notes payable	78,673	7,871
Other payables	74,194	54,589
Total payables	152,867	₩ 62,460
Company, excluding the controlling company [member] | POSCO Power Co Ltd [member]
Disclosure of transactions between related parties [line items]
Trade accounts and notes receivable	13,703
Total receivables	13,703
Other payables	66,856
Total payables	₩ 66,856

Related Party Transactions - _5

Related Party Transactions - Related Account Balances of Significant Transactions Between the Company, Excluding the Controlling Company, and Related Parties (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2018	Dec. 31, 2017
Company, excluding the controlling company [member]
Disclosure of transactions between related parties [line items]
Bad-debt allowance for receivables	₩ 102,694	₩ 4,217

Related Party Transactions - _6

Related Party Transactions - Significant Financial Transactions Between the Company, Excluding the Controlling Company, and Related Parties (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of transactions between related parties [line items]
Lend	₩ (627,783)	₩ (1,055,895)	₩ (603,332)
Collect	(941,962)	(667,045)	(557,064)
Company, excluding the controlling company [member] | METAPOLIS Co.,Ltd [member]
Disclosure of transactions between related parties [line items]
Beginning		13,270
Others		(13,270)
Ending			13,270
Company, excluding the controlling company [member] | New Songdo International City Development, LLC [member]
Disclosure of transactions between related parties [line items]
Beginning	282,775
Lend	150	484,644
Collect	(252,759)	(201,869)
Others	(30,166)
Ending		282,775
Company, excluding the controlling company [member] | Gale International Korea, LLC [member]
Disclosure of transactions between related parties [line items]
Beginning	2,000
Lend	8,500	2,000
Collect	(10,500)
Ending		2,000
Company, excluding the controlling company [member] | DMSA/AMSA [member]
Disclosure of transactions between related parties [line items]
Beginning	69,713	90,638
Lend	9,965	2,956
Collect	(342)
Others	(15,039)	(23,881)
Ending	64,297	69,713	90,638
Company, excluding the controlling company [member] | South-East Asia Gas Pipeline Company Ltd. [member]
Disclosure of transactions between related parties [line items]
Beginning	229,880	276,605
Lend		28,967
Collect	(47,569)	(46,252)
Others	8,796	(29,440)
Ending	191,107	229,880	276,605
Company, excluding the controlling company [member] | PT. batutua tembaga raya [member]
Disclosure of transactions between related parties [line items]
Beginning	29,048	38,120
Lend	4,678
Others	1,374	(9,072)
Ending	35,100	29,048	38,120
Company, excluding the controlling company [member] | PT. Tanggamus Electric Power [member]
Disclosure of transactions between related parties [line items]
Beginning	3,197	3,606
Others	1,226	(409)
Ending	4,423	3,197	3,606
Company, excluding the controlling company [member] | PT. wampu electric power [member]
Disclosure of transactions between related parties [line items]
Beginning	5,107	5,761
Others	223	(654)
Ending	5,330	5,107	5,761
Company, excluding the controlling company [member] | PT. POSMI Steel Indonesia [member]
Disclosure of transactions between related parties [line items]
Beginning	4,286	4,834
Collect	(2,200)
Others	150	(548)
Ending	2,236	4,286	4,834
Company, excluding the controlling company [member] | Nickel mining company SAS [member]
Disclosure of transactions between related parties [line items]
Beginning	59,668	60,425
Others	(4)	(757)
Ending	59,664	59,668	60,425
Company, excluding the controlling company [member] | AN KHANH NEW CITY DEVELOPMENT J.V. CO., LTD. [member]
Disclosure of transactions between related parties [line items]
Beginning		60,425
Others		(60,425)
Ending			60,425
Company, excluding the controlling company [member] | Zhongyue POSCO (Qinhuangdao) Tinplate Industrial Co., Ltd [member]
Disclosure of transactions between related parties [line items]
Beginning	5,357	6,647
Collect	(5,357)	(577)
Others		(713)
Ending		5,357	6,647
Company, excluding the controlling company [member] | KRAKATAU POS-CHEM DONG-SUH CHEMICAL [member]
Disclosure of transactions between related parties [line items]
Beginning	6,428	7,251
Others	281	(823)
Ending	6,709	6,428	7,251
Company, excluding the controlling company [member] | Hamparan Mulya [member]
Disclosure of transactions between related parties [line items]
Beginning		3,626
Collect		(3,626)
Ending			3,626
Company, excluding the controlling company [member] | POS-SEAH STEEL WIRE (TIANJIN) CO., Ltd [member]
Disclosure of transactions between related parties [line items]
Beginning		5,438
Collect		(5,438)
Ending			5,438
Company, excluding the controlling company [member] | POSCO SeAH Steel Wire(Nantong) Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Beginning	5,357	8,460
Lend	4,451
Collect	(6,454)	(2,262)
Others		(841)
Ending	3,354	5,357	8,460
Company, excluding the controlling company [member] | POS-SeAH Steel Wire (Thailand) Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Beginning	6,428	7,251
Collect		(1,142)
Others	281	319
Ending	6,709	6,428	7,251
Company, excluding the controlling company [member] | AMCI (WA) PTY LTD [member]
Disclosure of transactions between related parties [line items]
Beginning	92,061	91,775
Lend	3,795	4,327
Others	(5,376)	(4,041)
Ending	90,480	92,061	91,775
Company, excluding the controlling company [member] | POSCO(Yantai)Automotive Processing Center Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Beginning	5,357
Lend	5,564
Collect	(5,357)
Others	26	5,357
Ending	5,590	5,357
Company, excluding the controlling company [member] | POS-AUSTEM WUHAN AUTOMOTIVE CO.,LTD [member]
Disclosure of transactions between related parties [line items]
Beginning	8,571
Lend	8,902
Collect	(8,571)
Others	43	8,571
Ending	8,945	8,571
Company, excluding the controlling company [member] | SAMHWAN VINA CO., LTD [member]
Disclosure of transactions between related parties [line items]
Beginning	1,071
Collect	(1,071)
Others		1,071
Ending		1,071
Company, excluding the controlling company [member] | Associates and joint ventures [member]
Disclosure of transactions between related parties [line items]
Beginning	816,304	684,132
Lend	51,700	522,894
Collect	(340,180)	(261,166)
Others	(38,185)	(129,556)
Ending	489,639	₩ 816,304	₩ 684,132
Company, excluding the controlling company [member] | UITrans LRT Co., Ltd. [member]
Disclosure of transactions between related parties [line items]
Lend	5,695
Ending	₩ 5,695

Related Party Transactions - _7

Related Party Transactions - Significant Financial Transactions Between the Company, Excluding the Controlling Company, and Related Parties (Parenthetical) (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Company, excluding the controlling company [member] | DMSA/AMSA [member]
Disclosure of transactions between related parties [line items]
Loans converted to shares of DMSA/AMSA	₩ 17,559	₩ 13,712

Related Party Transactions - De

Related Party Transactions - Details of Compensation to Key Management Officers (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related party transactions [abstract]
Short-term benefits	₩ 115,618	₩ 112,688	₩ 90,916
Long-term benefits	13,400	8,632	17,905
Retirement benefits	21,658	20,422	17,870
Compensation to key management	₩ 150,676	₩ 141,742	₩ 126,691

Commitments and Contingencies -

Commitments and Contingencies - Contingent Liabilities on Outstanding Guarantees (Detail) - Dec. 31, 2018 ₩ in Millions	KRW (₩)	USD ($)	INR (₨)	IDR (Rp)	BRL (R$)	THB (฿)	AUD ($)	EUR (€)
Contingent liabilities on outstanding guarantees [member] | USD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	₩ 3,968,462	$ 3,549,290,606
Contingent liabilities on outstanding guarantees [member] | KRW [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	2,454,046
Contingent liabilities on outstanding guarantees [member] | Indonesia, Rupiahs
Disclosure of contingent liabilities [line items]
Guarantee amount	11,520			Rp 150,000,000,000
Contingent liabilities on outstanding guarantees [member] | India, Rupees
Disclosure of contingent liabilities [line items]
Guarantee amount	144		₨ 9,000,000
Contingent liabilities on outstanding guarantees [member] | THB [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	188,959					฿ 5,501,000,000
Contingent liabilities on outstanding guarantees [member] | EUR [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	58,841							€ 46,000,000
Contingent liabilities on outstanding guarantees [member] | AUD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	20,599						$ 26,147,711
Contingent liabilities on outstanding guarantees [member] | BRL [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	133,253				R$ 462554370
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | USD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	5,023,024	4,492,463,974
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | KRW [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	3,522,872
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | Indonesia, Rupiahs
Disclosure of contingent liabilities [line items]
Guarantee amount	11,520			150,000,000,000
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | India, Rupees
Disclosure of contingent liabilities [line items]
Guarantee amount	1,663
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | THB [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	188,959					5,501,000,000
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | EUR [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	58,841							46,000,000
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | AUD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	20,599						26,147,711
Contingent liabilities on outstanding guarantees [member] | Top of range [member] | BRL [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	133,686				464,060,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO Asia Co., Ltd. [member] | BOC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	111,810	100,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO ASSAN TST STEEL INDUSTRY [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	147,449	131,874,750
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO COATED STEEL (THAILAND) CO., LTD. [member] | The Great&CO Co., Ltd(SPC) [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	188,959					5,501,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO Maharashtra Steel Private Limited [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	188,285	168,397,800
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO MEXICO S.A. DE C.V. [member] | BOA and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	178,896	160,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO SS-VINA Co., Ltd [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	306,996	274,570,077
Contingent liabilities on outstanding guarantees [member] | Posco [member] | POSCO-VIETNAM Co., Ltd. [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	174,424	156,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | PT. KRAKATAU POSCO [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,226,821	1,097,236,405
Contingent liabilities on outstanding guarantees [member] | Posco [member] | CSP - Compania Siderurgica do Pecem [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	439,365	392,956,955
Contingent liabilities on outstanding guarantees [member] | Posco [member] | CSP - Compania Siderurgica do Pecem [member] | BNDES [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	133,253				462,554,370
Contingent liabilities on outstanding guarantees [member] | Posco [member] | LLP POSUK Titanium [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,772	15,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Nickel mining company SAS [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	58,841							46,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO Asia Co., Ltd. [member] | BOC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	111,810	100,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO ASSAN TST STEEL INDUSTRY [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	163,832	146,527,500
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO COATED STEEL (THAILAND) CO., LTD. [member] | The Great&CO Co., Ltd(SPC) [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	188,959					฿ 5,501,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO Maharashtra Steel Private Limited [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	566,712	506,853,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO MEXICO S.A. DE C.V. [member] | BOA and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	178,896	160,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO SS-VINA Co., Ltd [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	396,200	354,351,050
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | POSCO-VIETNAM Co., Ltd. [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	174,424	156,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | PT. KRAKATAU POSCO [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,509,770	1,350,300,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | CSP - Compania Siderurgica do Pecem [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	469,602	420,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | CSP - Compania Siderurgica do Pecem [member] | BNDES [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	133,686	464,060,000			R$ 464060000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | LLP POSUK Titanium [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,772	15,000,000
Contingent liabilities on outstanding guarantees [member] | Posco [member] | Top of range [member] | Nickel mining company SAS [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	58,841							€ 46,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | POSCO ASSAN TST STEEL INDUSTRY [member] | ING and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,383	14,652,750
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Daewoo Global Development. Pte., Ltd [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	219,167	169,017,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | DAEWOO POWER PNG Ltd. [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	53,222	47,600,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | POSCO DAEWOO INDIA PVT., LTD. [member] | Shinhan Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	87,203	77,990,903
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | PT. Bio Inti Agrindo [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	139,902	125,125,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | PT. Bio Inti Agrindo [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	11,520			150,000,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Golden Lace DAEWOO Company Limited [member] | Shinhan Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	6,708	6,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | POSCO DAEWOO CHINA CO., LTD. [member] | Mizuho [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	8,151	7,290,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | GLOBAL KOMSCO Daewoo LLC [member] | Industrial & Commercial Bank of China [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	9,196	8,225,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Ambatovy Project Investments Limited and others [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	13,451	12,030,434
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | POSCO ASSAN TST STEEL INDUSTRY [member] | ING and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,383	14,652,750
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | Daewoo Global Development. Pte., Ltd [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	219,167	169,017
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | DAEWOO POWER PNG Ltd. [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	53,222	47,600,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | POSCO DAEWOO INDIA PVT., LTD. [member] | Shinhan Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	167,044	149,400,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | PT. Bio Inti Agrindo [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	139,902	125,125,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | PT. Bio Inti Agrindo [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	11,520			Rp 150,000,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | Golden Lace DAEWOO Company Limited [member] | Shinhan Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	10,063	9,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | POSCO DAEWOO CHINA CO., LTD. [member] | Mizuho [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	8,945	8,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | Songdo Posco Family housing [member] | SHINYOUNG SECURITIES CO., LTD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	10,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | GLOBAL KOMSCO Daewoo LLC [member] | Industrial & Commercial Bank of China [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	9,196	8,225,000
Contingent liabilities on outstanding guarantees [member] | POSCO DAEWOO Corporation [member] | Top of range [member] | Ambatovy Project Investments Limited and others [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	97,580	87,272,727
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Daewoo Global Development. Pte., Ltd [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	182,958	163,633,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | POSCO E&C Vietnam Co., Ltd. [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	52,551	47,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd [member] | Woori Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	158,770	142,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	144		9,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | Woori Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	2,348	2,100,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | PT. POSCO E&C INDONESIA [member] | POSCO Asia Co., Ltd. And others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	12,187	10,900,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | New Songdo International City Development, LLC [member] | Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	432,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | UITrans LRT Co., Ltd. [member] | Kookmin Bank and Other [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	3,766
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Chuncheon Energy Co., Ltd. [member] | Kookmin Bank and Other [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	941
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | JB CLARK HILLS [member] | Korea Investment and securities co. ltd [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	30,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Ecocity Company Limited and Others [member] | Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	545,893
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | Daewoo Global Development. Pte., Ltd [member] | SMBC and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	182,958	163,633,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | Songdo Posco Family housing [member] | SHINYOUNG SECURITIES CO., LTD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	10,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | POSCO E&C Vietnam Co., Ltd. [member] | Export-Import Bank of Korea [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	52,551	47,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd [member] | Woori Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	165,479	148,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,663
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | Woori Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	2,348	2,100,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | PT. POSCO E&C INDONESIA [member] | POSCO Asia Co., Ltd. And others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	12,187	10,900,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | New Songdo International City Development, LLC [member] | Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	440,000	440,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | UITrans LRT Co., Ltd. [member] | Kookmin Bank and Other [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	20,740	20,740
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | Chuncheon Energy Co., Ltd. [member] | Kookmin Bank and Other [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	11,600	11,600
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | Pohang E&E Co,. Ltd. [member] | Heungkuk Life Insurance Co. LTD [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	6,500	6,500
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | JB CLARK HILLS [member] | Korea Investment and securities co. ltd [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	40,000	40,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | Ecocity Company Limited and Others [member] | Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,524,314	1,524,314
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | PT.POSCO ICT INDONESIA [member] | POSCO Asia Co., Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,677	1,500,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Incheon-Gimpo Expressway Co., Ltd. [member] | Korea Development Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	100,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | UITrans LRT Co., Ltd. [member] | Kookmin Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	76,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | SMS Energy and others [member] | KEB Hana Bank and Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	60,519
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Hyochun CO., LTD [member] | Kyobo Securities Co, Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	39,575
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | BLT Enterprise and others [member] | Kyobo Life Insurance Co., Ltd and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,165,352
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | PT.POSCO ICT INDONESIA [member] | POSCO Asia Co., Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,677	1,500,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | Incheon-Gimpo Expressway Co., Ltd. [member] | Korea Development Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	100,000	100,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | UITrans LRT Co., Ltd. [member] | Kookmin Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	76,000	76,000
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | SMS Energy and others [member] | KEB Hana Bank and Others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	78,791	78,791
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | Hyochun CO., LTD [member] | Kyobo Securities Co, Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	39,575	39,575
Contingent liabilities on outstanding guarantees [member] | POSCO ICT [member] | Top of range [member] | BLT Enterprise and others [member] | Kyobo Life Insurance Co., Ltd and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,165,352	1,165,352
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | PT.Krakatau Posco Chemtech Calcination [member] | POSCO Asia Co., Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,101	14,400,000
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | KRAKATAU POS-CHEM DONG-SUH CHEMICAL [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	885	791,667
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | POS INFRA AUTO [member] | Korea Development Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	872	780,000
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | Top of range [member] | PT.Krakatau Posco Chemtech Calcination [member] | POSCO Asia Co., Ltd. [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	16,995	15,200,000
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | Top of range [member] | KRAKATAU POS-CHEM DONG-SUH CHEMICAL [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	1,274	1,140,000
Contingent liabilities on outstanding guarantees [member] | POSCO M-TECH [member] | Top of range [member] | POS INFRA AUTO [member] | Korea Development Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	872	780,000
Contingent liabilities on outstanding guarantees [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member] | Myanmar POSCO C&C Company, Limited [member] | POSCO Asia Co., Ltd. And others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	15,639	13,986,947
Contingent liabilities on outstanding guarantees [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member] | Top of range [member] | Myanmar POSCO C&C Company, Limited [member] | POSCO Asia Co., Ltd. And others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	15,639	13,986,947
Contingent liabilities on outstanding guarantees [member] | POSCO ENERGY CO., LTD. [member] | PT. Krakatau Posco Energy [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	135,549	121,231,918
Contingent liabilities on outstanding guarantees [member] | POSCO ENERGY CO., LTD. [member] | POSCO SINGAPORE LNG TRADING PTE. LTD [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	44,724	40,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENERGY CO., LTD. [member] | Top of range [member] | PT. Krakatau Posco Energy [member] | Export-Import Bank of Korea and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	216,800	193,900,000
Contingent liabilities on outstanding guarantees [member] | POSCO ENERGY CO., LTD. [member] | Top of range [member] | POSCO SINGAPORE LNG TRADING PTE. LTD [member] | SMBC [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	44,724	$ 40,000,000
Contingent liabilities on outstanding guarantees [member] | POSCO AUSTRALIA PTY LTD [member] | Department of Trade and Investment (NSW Government) [member] | Woori Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	20,599						26,147,711
Contingent liabilities on outstanding guarantees [member] | POSCO AUSTRALIA PTY LTD [member] | Top of range [member] | Department of Trade and Investment (NSW Government) [member] | Woori Bank and others [member]
Disclosure of contingent liabilities [line items]
Guarantee amount	₩ 20,599						$ 26,147,711
Top of range [member] | Top of range [member] | India, Rupees
Disclosure of contingent liabilities [line items]
Guarantee amount | ₨			104,000,000
Top of range [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | KEB Hana Bank [member]
Disclosure of contingent liabilities [line items]
Guarantee amount | ₨			₨ 104,000,000

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail) T in Thousands, ₩ in Millions	12 Months Ended
	Dec. 31, 2018KRW (₩)VesselT	Dec. 31, 2018USD ($)VesselT	Dec. 31, 2018USD ($)	Dec. 31, 2017KRW (₩)
Disclosure of contingent liabilities [line items]
Borrowings	₩ 20,209,270			₩ 21,063,657
Posco [member]
Disclosure of contingent liabilities [line items]
Remaining iron ore to be purchased | T	100,000	100,000
Remaining coal to be purchased | T	14,000	14,000
Liquefied natural gas to be purchased | T	550	550
Liquefied natural gas terms	20 years	20 years
Number of vessels for transportation of raw materials | Vessel	38	38
Average remaining contract period	10 years	10 years
Freight expense | $			$ 668,000,000
Posco [member] | Korea National Oil Corporation [member]
Disclosure of contingent liabilities [line items]
Borrowings | $			1,020,000
Posco [member] | Bottom of range [member]
Disclosure of contingent liabilities [line items]
Iron ore and coal contracts terms	3 years	3 years
Nickel contracts terms	1 year	1 year
Posco [member] | Top of range [member] | Korea National Oil Corporation [member]
Disclosure of contingent liabilities [line items]
Borrowings | $			$ 6,490,000
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member]
Disclosure of contingent liabilities [line items]
Completions guarantees provided	₩ 395,162
Construction guarantees received	179,619
POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Top of range [member]
Disclosure of contingent liabilities [line items]
Foreign currency guarantee | $		$ 2,517,000,000
Busan E&E Co. [member]
Disclosure of contingent liabilities [line items]
Supplementary fund				₩ 9,800
Woori Bank and others [member]
Disclosure of contingent liabilities [line items]
Foreign currency guarantee | $		$ 763,000,000
POSCO ICT [member] | Korea Software Financial Cooperative [member]
Disclosure of contingent liabilities [line items]
Contingent liabilities guarantee amount	131,117
POSCO ICT [member] | Seoul Guarantee Insurance [member]
Disclosure of contingent liabilities [line items]
Contingent liabilities guarantee amount	8,939
POSCO ICT [member] | Engineering Guarantee Insurance [member]
Disclosure of contingent liabilities [line items]
Contingent liabilities guarantee amount	₩ 305

Commitments and Contingencies_3

Commitments and Contingencies - Litigations in Progress (Detail) - 12 months ended Dec. 31, 2018 ₺ in Thousands, ₨ in Thousands, ₨ in Thousands, ฿ in Thousands, ¥ in Thousands, Rp in Thousands, R$ in Thousands, $ in Thousands, $ in Thousands, ₩ in Millions	KRW (₩)LegalMatter	USD ($)	INR (₨)	PKR (₨)	CAD ($)	IDR (Rp)	BRL (R$)	TRY (₺)	CNY (¥)	THB (฿)
Lawsuits provision [member]
Disclosure of contingent liabilities [line items]
Estimated lawsuits	122
Provision for legal contingencies and claims | ₩	₩ 50,888
Litigations in progress [member] | Posco [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	27
Claim amount | ₩	₩ 75,218
Claim amount | ₩	₩ 75,218
Description	Lawsuit on claim for employee right and others(*1)
Litigations in progress [member] | POSCO DAEWOO Corporation [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	10
Claim amount | ₩	₩ 20,049
Claim amount | ₩	₩ 20,049
Description	Litigation for confirmation of deposit bond and others
Litigations in progress [member] | POSCO DAEWOO Corporation [member] | CAD [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 64,808				$ 79,000
Claim amount	₩ 64,808				$ 79,000
Description	Lawsuit on claim for damages
Litigations in progress [member] | POSCO DAEWOO Corporation [member] | India [member]
Disclosure of contingent liabilities [line items]
Legal actions	3
Claim amount	₩ 72,254		₨ 4,518,694
Claim amount	₩ 72,254		4,518,694
Description	Lawsuit on claim for payment on guarantees and others(*1)
Litigations in progress [member] | POSCO DAEWOO Corporation [member] | US [member]
Disclosure of contingent liabilities [line items]
Legal actions	5
Claim amount	₩ 32,160	$ 28,763
Claim amount	₩ 32,160	28,763
Description	Lawsuit on claim for damages and others
Litigations in progress [member] | POSCO DAEWOO Corporation [member] | Pakistan [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 1,003			₨ 124,775
Claim amount	₩ 1,003			₨ 124,775
Description	Lawsuit on claim for damages
Litigations in progress [member] | POSCO ENGINEERING & CONSTRUCTION CO., LTD. [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	120
Claim amount | ₩	₩ 442,812
Claim amount | ₩	₩ 442,812
Description	Lawsuit on claim for damages and others(*1)
Litigations in progress [member] | POSCO ICT [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	11
Claim amount | ₩	₩ 6,452
Claim amount | ₩	₩ 6,452
Description	Lawsuit on claim for damages and others
Litigations in progress [member] | POSCO ICT [member] | US [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 2,103	1,881
Claim amount	₩ 2,103	1,881
Description	Lawsuit on claim for damages
Litigations in progress [member] | POSCO ICT [member] | Brazil [Member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 2,933						R$ 10182
Claim amount	₩ 2,933						10,182
Description	Lawsuit on revocation of claim for damage
Litigations in progress [member] | POSCO A&C [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	8
Claim amount | ₩	₩ 2,752
Claim amount | ₩	₩ 2,752
Description	Lawsuit on claim for payment on construction and others
Litigations in progress [member] | POSCO ENERGY CO., LTD. [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	3
Claim amount | ₩	₩ 3,039
Claim amount | ₩	₩ 3,039
Description	Lawsuit on claim for damages and others
Litigations in progress [member] | POSCO E&C CHINA Co., Ltd. [member] | China [member]
Disclosure of contingent liabilities [line items]
Legal actions	3
Claim amount	₩ 7,234								¥ 44,446
Claim amount	₩ 7,234								44,446
Description	Lawsuit over contract dispute and others
Litigations in progress [member] | POSCO COATED & COLOR STEEL Co., Ltd. [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount | ₩	₩ 1,400
Claim amount | ₩	₩ 1,400
Description	Lawsuit on claim for payment
Litigations in progress [member] | POSCO ENGINEERING (THAILAND) CO., LTD. [member] | Thailand [Member]
Disclosure of contingent liabilities [line items]
Legal actions	2
Claim amount	₩ 17,491									฿ 509,191
Claim amount	₩ 17,491									฿ 509,191
Description	Lawsuit on claim for payment on construction and others
Litigations in progress [member] | PT. KRAKATAU POSCO [member] | Indonesia [Member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 16,236					Rp 211,407,872
Claim amount	₩ 16,236					Rp 211,407,872
Description	Lawsuit on claim for payment on construction
Litigations in progress [member] | POSCO E&C Vietnam Co., Ltd. [member] | US [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 4,354	3,894
Claim amount	₩ 4,354	3,894
Description	Lawsuit on claim for payment on construction
Litigations in progress [member] | POSCO-China Qingdao Processing Center Co., Ltd. [member] | China [member]
Disclosure of contingent liabilities [line items]
Legal actions	2
Claim amount	₩ 1,103								6,774
Claim amount	₩ 1,103								6,774
Description	Lawsuit over contract dispute and others
Litigations in progress [member] | POSCO-Malaysia SDN. BHD. [member] | MYR [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Description	Lawsuit on claim for infringement of right
Litigations in progress [member] | Pos-Sea Pte Ltd [member] | US [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 13,474	12,051
Claim amount	₩ 13,474	$ 12,051
Description	Lawsuit over contract dispute
Litigations in progress [member] | POSCO INDIA HOLDINGS PRIVATE LIMITED [member] | India, Rupees
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 3,518		220,000
Claim amount	₩ 3,518		220,000
Description	Lawsuit over contract dispute
Litigations in progress [member] | POSCO TNPC Otomotiv Celik San. Ve Tic. A.S [member] | Turkey [Member]
Disclosure of contingent liabilities [line items]
Legal actions	8
Claim amount	₩ 22							₺ 102
Claim amount	₩ 22							102
Description	Lawsuit over industrial accidents and others
Litigations in progress [member] | POSCO India Steel Distribution Center Private Ltd [member] | India [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 3,578		223,795
Claim amount	₩ 3,578		₨ 223,795
Description	Lawsuit on claim for tax restitution
Litigations in progress [member] | POSCO(Dalian) IT Center Development Co., Ltd. [member] | China [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 690								4,240
Claim amount	₩ 690								¥ 4,240
Description	Lawsuit over contract dispute
Litigations in progress [member] | Brazil Sao Paulo Steel Processing Center [member] | Brazil [Member]
Disclosure of contingent liabilities [line items]
Legal actions	3
Claim amount	₩ 1,346						4,671
Claim amount	₩ 1,346						4,671
Description	Lawsuit on claim for labor and others
Litigations in progress [member] | POSCO ENGINEERING & CONSTRUCTION DO BRAZIL LTDA. [member] | Brazil [Member]
Disclosure of contingent liabilities [line items]
Legal actions	148
Claim amount	₩ 44,944						156,011
Claim amount	₩ 44,944						R$ 156011
Description	Lawsuit on claim for payment on construction and others
Litigations in progress [member] | POSCO ASSAN TST STEEL INDUSTRY [member] | Turkey [Member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount	₩ 1,027							4,870
Claim amount	₩ 1,027							₺ 4,870
Description	Lawsuit on compensation
Litigations in progress [member] | HONG KONG POSCO E&C (CHINA) INVESTMENT Co., Ltd [member] | Korea [member]
Disclosure of contingent liabilities [line items]
Legal actions	1
Claim amount | ₩	₩ 3,305
Claim amount | ₩	₩ 3,305
Description	Lawsuit on claim for payment

Additional Information of Cas_3

Additional Information of Cash Flow Statements - Changes in Operating Assets and Liabilities (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from (used in) operating activities [abstract]
Trade accounts and notes receivable	₩ 17,806	₩ 63,075	₩ 273,419
Other receivables	(20,786)	113,740	191,591
Inventories	(1,451,009)	(1,435,170)	(889,998)
Other current assets	1,118	110,688	(287,377)
Other non-currentassets	5,974	12,455	33,584
Trade accounts and notes payable	379,742	(607,999)	769,337
Other payables	(111,893)	(26,922)	(179,174)
Other current liabilities	(199,981)	338,273	2,490
Provisions	(116,790)	(145,763)	(124,884)
Payments of severance benefits	(189,165)	(185,220)	(278,278)
Plan assets	(245,214)	3,815	(138,854)
Other non-currentliabilities	(175,528)	(82,605)	223,574
Changes in operating cash flows	₩ (2,105,726)	₩ (1,841,633)	₩ (404,570)

Additional Information of Cas_4

Additional Information of Cash Flow Statements - Changes in Liabilities Arising from Financial Activities (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Short-term borrowings [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning	₩ 8,174,818	₩ 7,979,727
Changes from financing cash flows	(854,554)	558,083
Changes arising from obtaining or losing control of subsidiaries or other business	(342)	(12,469)
The effect of changes in foreign exchange rates	167,858	(350,523)
Other changes:	0	0
Ending	7,487,780	8,174,818
Long-term borrowings [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning	12,888,839	14,725,271
Changes from financing cash flows	(373,862)	(1,410,033)
Changes arising from obtaining or losing control of subsidiaries or other business		3,299
The effect of changes in foreign exchange rates	200,308	(435,170)
Other changes:	0	0
Amortization of discount on debentures issued	6,205	5,472
Ending	12,721,490	12,888,839
Dividend payable [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning	7,213	7,770
Changes from financing cash flows	(770,099)	(931,232)
The effect of changes in foreign exchange rates	(5,573)
Other changes:	0	0
Decrease in retained earnings	704,444	863,579
Decrease in non-controllinginterest	72,688	67,096
Ending	8,673	7,213
Finance lease liabilities [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning	93,018	114,409
Changes from financing cash flows	(14,955)	(10,536)
The effect of changes in foreign exchange rates	(7,766)	(10,855)
Other changes:	0	0
Increase in finance lease assets	24,457
Ending	94,754	93,018
Derivatives that hedge long-term borrowings [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning	119,320	(52,373)
Changes from financing cash flows	(17,237)
Changes in fair values	(58,666)	171,693
Other changes:	0	0
Ending	₩ 43,417	₩ 119,320

Operating Segments - Informatio

Operating Segments - Information about Reportable Segments (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of operating segments [line items]
Revenues	₩ 65,154,636	₩ 60,186,867	₩ 52,939,771
Interest income	337,258	212,451	182,475
Interest expenses	(741,296)	(653,115)	(658,726)
Depreciation and amortization	(3,267,629)	(3,297,420)	(3,213,847)
Impairment loss on property, plant and equipment and others	(1,451,397)	(302,967)	(368,939)
Impairment loss on available-for-sale financial assets		(123,214)	(248,404)
Share of profit or loss of investment in associates and joint ventures	112,635	10,540	(88,677)
Income tax expense	(1,683,630)	(1,185,740)	(379,544)
Profit (loss)	1,932,386	2,909,311	1,032,065
Assets	78,776,991	79,785,629
Liabilities	32,104,377	32,458,904
Reportable segments [member]
Disclosure of operating segments [line items]
Revenues	102,258,628	95,059,704	81,885,203
Interest income	373,926	280,488	245,454
Interest expenses	(863,560)	(757,963)	(759,001)
Depreciation and amortization	(3,325,415)	(3,360,366)	(3,276,416)
Impairment loss on property, plant and equipment and others	(1,343,360)	(336,719)	(243,282)
Impairment loss on available-for-sale financial assets		(127,319)	(314,446)
Share of profit or loss of investment in associates and joint ventures	(1,049,335)	(1,721)	(554,872)
Income tax expense	(1,664,258)	(1,274,696)	(463,009)
Profit (loss)	1,331,419	3,160,761	135,026
Assets	101,878,001	101,542,757	101,525,764
Investment in subsidiaries, associates and joint ventures	18,922,074	19,113,739	19,206,073
Acquisition of non-currentassets	2,652,860	2,670,224	2,801,687
Liabilities	40,264,320	39,809,138	41,917,003
Reportable segments [member] | External customers [member]
Disclosure of operating segments [line items]
Revenues	64,977,777	60,655,100	53,083,513
Reportable segments [member] | Internal customers [member]
Disclosure of operating segments [line items]
Revenues	37,280,851	34,404,604	28,801,690
Reportable segments [member] | Intersegment [member]
Disclosure of operating segments [line items]
Revenues	24,344,571	22,823,501	17,132,284
Reportable segments [member] | Steel [member]
Disclosure of operating segments [line items]
Revenues	50,421,222	47,611,378	42,906,170
Interest income	199,016	128,827	126,210
Interest expenses	(468,681)	(422,357)	(459,345)
Depreciation and amortization	(2,812,666)	(2,856,133)	(2,788,535)
Impairment loss on property, plant and equipment and others	(1,057,474)	(149,840)	(99,165)
Impairment loss on available-for-sale financial assets		(95,261)	(225,225)
Share of profit or loss of investment in associates and joint ventures	(733,879)	8,352	(211,084)
Income tax expense	(1,307,292)	(977,853)	(495,874)
Profit (loss)	1,268,313	2,790,855	1,511,383
Assets	70,976,493	70,017,816	69,914,939
Investment in subsidiaries, associates and joint ventures	16,099,692	16,116,654	16,109,360
Acquisition of non-currentassets	2,239,467	2,033,184	2,334,842
Liabilities	20,289,037	19,057,249	20,292,764
Reportable segments [member] | Steel [member] | External customers [member]
Disclosure of operating segments [line items]
Revenues	32,358,009	30,230,368	26,844,154
Reportable segments [member] | Steel [member] | Internal customers [member]
Disclosure of operating segments [line items]
Revenues	18,063,213	17,381,010	16,062,016
Reportable segments [member] | Steel [member] | Intersegment [member]
Disclosure of operating segments [line items]
Revenues	12,496,287	12,004,614	8,992,783
Reportable segments [member] | Trading [member]
Disclosure of operating segments [line items]
Revenues	38,318,855	34,878,203	26,420,104
Interest income	36,437	32,799	40,424
Interest expenses	(189,165)	(121,967)	(70,841)
Depreciation and amortization	(210,493)	(206,490)	(165,863)
Impairment loss on property, plant and equipment and others	(86,085)	(140,839)	(45,995)
Impairment loss on available-for-sale financial assets			(28,988)
Share of profit or loss of investment in associates and joint ventures	(160,085)		(53,586)
Income tax expense	(52,914)	(109,710)	(18,629)
Profit (loss)	49,264	112,661	53,244
Assets	15,550,854	14,139,098	13,580,179
Investment in subsidiaries, associates and joint ventures	1,379,045	1,134,798	1,100,973
Acquisition of non-currentassets	132,017	286,185	249,597
Liabilities	11,454,079	10,386,294	10,134,170
Reportable segments [member] | Trading [member] | External customers [member]
Disclosure of operating segments [line items]
Revenues	22,407,717	20,802,207	16,774,078
Reportable segments [member] | Trading [member] | Internal customers [member]
Disclosure of operating segments [line items]
Revenues	15,911,138	14,075,996	9,646,026
Reportable segments [member] | Trading [member] | Intersegment [member]
Disclosure of operating segments [line items]
Revenues	8,743,666	8,043,643	5,296,847
Reportable segments [member] | Construction [member]
Disclosure of operating segments [line items]
Revenues	7,320,734	7,285,530	7,482,051
Interest income	115,019	100,922	65,256
Interest expenses	(111,101)	(112,983)	(102,292)
Depreciation and amortization	(36,840)	(42,123)	(57,719)
Impairment loss on property, plant and equipment and others	(82,521)	(37,476)	(9,426)
Impairment loss on available-for-sale financial assets		(18,637)	(35,331)
Share of profit or loss of investment in associates and joint ventures	(155,371)	(8,555)	(283,833)
Income tax expense	(238,441)	(109,961)	107,520
Profit (loss)	234	24,545	(1,403,712)
Assets	7,333,221	8,609,753	9,501,046
Investment in subsidiaries, associates and joint ventures	511,230	668,392	795,445
Acquisition of non-currentassets	49,095	99,190	25,533
Liabilities	4,386,852	5,744,693	6,780,380
Reportable segments [member] | Construction [member] | External customers [member]
Disclosure of operating segments [line items]
Revenues	6,769,410	6,886,606	6,768,348
Reportable segments [member] | Construction [member] | Internal customers [member]
Disclosure of operating segments [line items]
Revenues	551,324	398,924	713,703
Reportable segments [member] | Construction [member] | Intersegment [member]
Disclosure of operating segments [line items]
Revenues	465,057	329,215	557,526
Reportable segments [member] | Other reportable segment [member]
Disclosure of operating segments [line items]
Revenues	6,197,817	5,284,593	5,076,878
Interest income	23,454	17,940	13,564
Interest expenses	(94,613)	(100,656)	(126,523)
Depreciation and amortization	(265,416)	(255,620)	(264,299)
Impairment loss on property, plant and equipment and others	(117,280)	(8,564)	(88,696)
Impairment loss on available-for-sale financial assets		(13,421)	(24,902)
Share of profit or loss of investment in associates and joint ventures		(1,518)	(6,369)
Income tax expense	(65,611)	(77,172)	(56,026)
Profit (loss)	13,608	232,700	(25,889)
Assets	8,017,433	8,776,090	8,529,600
Investment in subsidiaries, associates and joint ventures	932,107	1,193,895	1,200,295
Acquisition of non-currentassets	232,281	251,665	191,715
Liabilities	4,134,352	4,620,902	4,709,689
Reportable segments [member] | Other reportable segment [member] | External customers [member]
Disclosure of operating segments [line items]
Revenues	3,442,641	2,735,919	2,696,933
Reportable segments [member] | Other reportable segment [member] | Internal customers [member]
Disclosure of operating segments [line items]
Revenues	2,755,176	2,548,674	2,379,945
Reportable segments [member] | Other reportable segment [member] | Intersegment [member]
Disclosure of operating segments [line items]
Revenues	₩ 2,639,561	₩ 2,446,029	₩ 2,285,128

Operating Segments - Reconcilia

Operating Segments - Reconciliation of Segment Revenues, Profit or Loss, Assets and Liabilities and Other Significant Items (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of operating segments [line items]
Revenue	₩ 65,154,636	₩ 60,186,867	₩ 52,939,771
Profit before income tax expense	3,616,016	4,095,051	1,411,609
Assets	78,776,991	79,785,629
Liabilities	32,104,377	32,458,904
Interest income	337,258	212,451	182,475
Interest expenses	(741,296)	(653,115)	(658,726)
Depreciation and amortization	(3,267,629)	(3,297,420)	(3,213,847)
Share of profit or loss of investment in associates		10,540	(88,677)
Share of profit or loss of investment in associates	112,635	10,540	(88,677)
Income tax expense	(1,683,630)	(1,185,740)	(379,544)
Impairment loss on property, plant and equipment and others	(1,451,397)	(302,967)	(368,939)
Impairment loss on available-for-sale financial assets		(123,214)	(248,404)
Other significant items	(6,694,059)	(5,339,465)	(4,775,662)
Reportable segments [member]
Disclosure of operating segments [line items]
Revenue	102,258,628	95,059,704	81,885,203
Profit before income tax expense	1,331,419	3,160,761	135,026
Assets	101,878,001	101,542,757	101,525,764
Liabilities	40,264,320	39,809,138	41,917,003
Interest income	373,926	280,488	245,454
Interest expenses	(863,560)	(757,963)	(759,001)
Depreciation and amortization	(3,325,415)	(3,360,366)	(3,276,416)
Share of profit or loss of investment in associates		(1,721)	(554,872)
Share of profit or loss of investment in associates	(1,049,335)	(1,721)	(554,872)
Income tax expense	(1,664,258)	(1,274,696)	(463,009)
Impairment loss on property, plant and equipment and others	(1,343,360)	(336,719)	(243,282)
Impairment loss on available-for-sale financial assets		(127,319)	(314,446)
Other significant items	(7,872,002)	(5,578,296)	(5,365,572)
Investments in subsidiaries, associates and joint ventures [member]
Disclosure of operating segments [line items]
Assets	15,272,243	15,555,972
Goodwill and corporate FV adjustments [member]
Disclosure of operating segments [line items]
Profit before income tax expense	(77,756)	(84,370)	(123,110)
Assets	2,722,115	3,368,333
Liabilities	321,320	483,693
Interest expenses	1,035	1,304	(807)
Depreciation and amortization	(103,932)	(106,195)	(104,949)
Share of profit or loss of investment in associates			(38,732)
Income tax expense	25,921	21,270	21,945
Impairment loss on property, plant and equipment and others	(779)	(867)
Other significant items	(77,755)	(84,488)	(122,543)
Elimination of inter-segment amounts [member]
Disclosure of operating segments [line items]
Revenue	(37,280,851)	(34,404,604)	(28,801,690)
Profit before income tax expense	638,401	(102,922)	1,036,253
Assets	11,079,608	10,330,159
Liabilities	(9,096,926)	(8,731,880)
Interest income	(36,668)	(68,037)	(62,979)
Interest expenses	121,229	103,544	101,082
Depreciation and amortization	161,718	169,141	167,518
Share of profit or loss of investment in associates		12,261	504,927
Share of profit or loss of investment in associates	1,161,970
Income tax expense	(32,420)	47,203	56,379
Impairment loss on property, plant and equipment and others	(107,258)	34,619	(125,657)
Impairment loss on available-for-sale financial assets		4,105	66,042
Other significant items	1,268,571	302,836	707,312
Income tax expense [member]
Disclosure of operating segments [line items]
Profit before income tax expense	1,670,757	1,206,223	384,685
Basis difference [member]
Disclosure of operating segments [line items]
Revenue	176,859	(468,233)	(143,742)
Profit before income tax expense	53,195	(84,641)	(21,245)
Assets	528,726	760,670
Liabilities	615,663	897,953
Income tax expense	(12,873)	20,483	5,141
Other significant items	₩ (12,873)	₩ 20,483	₩ 5,141

Operating Segments - Revenue an

Operating Segments - Revenue and Non-current Assets by Geographic Area (Detail) - KRW (₩) ₩ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of geographical areas [line items]
Revenue	₩ 65,154,636	₩ 60,186,867	₩ 52,939,771
Non-current assets	36,117,713	38,900,718
Domestic [member]
Disclosure of geographical areas [line items]
Non-current assets	28,298,293	30,790,462
Japan [member]
Disclosure of geographical areas [line items]
Non-current assets	146,490	162,328
China [member]
Disclosure of geographical areas [line items]
Non-current assets	1,185,828	1,284,561
Indonesia [Member]
Disclosure of geographical areas [line items]
Non-current assets	2,711,032	2,750,084
Asia-other [member]
Disclosure of geographical areas [line items]
Non-current assets	2,356,904	2,516,715
North America [member]
Disclosure of geographical areas [line items]
Non-current assets	173,914	277,249
Other countries [member]
Disclosure of geographical areas [line items]
Non-current assets	1,245,252	1,119,319
Basis difference [member]
Disclosure of geographical areas [line items]
Revenue	176,859	(468,233)	(143,742)
Reportable segments [member]
Disclosure of geographical areas [line items]
Revenue	102,258,628	95,059,704	81,885,203
Reportable segments [member] | External customers [member]
Disclosure of geographical areas [line items]
Revenue	64,977,777	60,655,100	53,083,513
Reportable segments [member] | External customers [member] | Domestic [member]
Disclosure of geographical areas [line items]
Revenue	41,671,930	38,882,220	34,883,941
Reportable segments [member] | External customers [member] | Japan [member]
Disclosure of geographical areas [line items]
Revenue	2,084,061	2,200,405	1,892,022
Reportable segments [member] | External customers [member] | China [member]
Disclosure of geographical areas [line items]
Revenue	6,945,266	6,731,214	5,908,046
Reportable segments [member] | External customers [member] | Indonesia [Member]
Disclosure of geographical areas [line items]
Revenue	1,592,046	1,266,572	908,361
Reportable segments [member] | External customers [member] | Asia-other [member]
Disclosure of geographical areas [line items]
Revenue	7,312,486	6,483,981	4,741,482
Reportable segments [member] | External customers [member] | North America [member]
Disclosure of geographical areas [line items]
Revenue	1,834,534	1,725,120	1,899,291
Reportable segments [member] | External customers [member] | Other countries [member]
Disclosure of geographical areas [line items]
Revenue	₩ 3,537,454	₩ 3,365,588	₩ 2,850,370