BUSINESS SEGMENT INFORMATION AND SELECTED FOREIGN CURRENCY TRANSLATION ITEMS - Additional Information (Detail) $ in Millions		12 Months Ended
		Dec. 31, 2025 USD ($) segment	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of reportable insurance business segments | segment		2
Net earned premiums	[1]	$ 13,548	$ 13,440	$ 14,123
Receivables		835	779
Premiums receivable, allowance for credit loss		107	108
Aflac Re Bermuda
Segment Reporting Information [Line Items]
Net earned premiums		$ 692	$ 568	$ 258
Aflac Japan
Segment Reporting Information [Line Items]
Percentage of the Company's total revenues		53.00%	55.00%	60.00%
Percentage of the Company's total assets		76.00%	77.00%
Net earned premiums		$ 6,744	$ 6,930	$ 8,047
Receivables		$ 167	$ 197
Percentage of total receivables related to Aflac Japan's operations		20.00%	25.30%

[1] Includes a gain (loss) of $(52), $(81) and $20 in 2025, 2024 and 2023, respectively, related to remeasurement of the deferred profit liability for limited-payment contracts.