Schedule II - Aflac Incorporated (Parent Only) - Additional Information (Detail) ¥ in Billions	12 Months Ended
Dec. 31, 2016 JPY (¥)
Parent Company \| Yen Denominated Uridashi and Samurai Notes
Condensed Financial Statements, Captions [Line Items]
Extinguishment of notes	¥ 2.0

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

No definition available.

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