STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Aflac Japan
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	$ 9,000	$ 7,800
Aflac
Statutory Accounting Practices [Line Items]
Amount available for dividend distribution without prior approval from regulatory agency	872
Dividends declared	853
Aflac New York
Statutory Accounting Practices [Line Items]
Dividends declared	$ 30

Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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-SubTopic 10
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Amount of dividends that can be declared or paid without approval of regulatory agency.

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-Name Accounting Standards Codification
-Topic 235
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- Definition

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

+ References

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-Name Accounting Standards Codification
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-SubTopic 210
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