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Investments in Associates and Joint Ventures - Summary of Reconciliation of Carrying Amount of Interests in the Associates and Joint Ventures (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
K Bank Inc. [member]
Disclosure of information about unconsolidated structured entities controlled by investment entity [line items]
Percentage of non-voting convertible stock are excluded	8.80%	8.00%

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- Definition

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

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No definition available.

+ Details

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- Definition

Proportion of non-voting rights in associate.

+ References

No definition available.

+ Details

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- Details

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