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v3.21.1

Post-Employment Benefits - Summary of Amount Recognized in the Consolidated Balance Sheet (Parenthetical) (Detail) - SEK (kr) kr in Millions | Dec. 31, 2020 | Dec. 31, 2019
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Disclosure Of Defined Benefit Plans [Abstract] |  |
Effect of asset ceiling | kr (518) | kr (833)

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- Definition Defined Benefit Obligation Effect of Asset Ceiling + References No definition available. + Details
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Namespace Prefix: | eric_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- References No definition available. + Details
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Namespace Prefix: | ifrs-full_
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Balance Type: | na
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