Revenue from Contracts with Customers and Relevant Contract Assets and Liabilities - Detail Analysis of Contract Costs Recognized as Assets (Detail) - KRW (₩) ₩ in Millions	Dec. 31, 2020	Dec. 31, 2019
Incremental cost of contract establishment [Member]
Statement [Line Items]
Incremental cost of contract establishment	₩ 1,726,191	₩ 1,764,009
Cost of Contract performance [Member]
Statement [Line Items]
Incremental cost of contract establishment	₩ 78,757	₩ 85,234

The amount of assets recognised from the costs to obtain or fulfil contracts with customers. The costs to obtain a contract with a customer are the incremental costs of obtaining the contract that the entity would not have incurred if the contract had not been obtained. The costs to fulfil a contract with a customer are the costs that relate directly to a contract or to an anticipated contract that the entity can specifically identify.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2020-01-01
-Paragraph 128
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_128_a&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_AssetsRecognisedFromCostsToObtainOrFulfilContractsWithCustomers
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant