STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Aflac Re Bermuda
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	$ 991,000,000	$ 581,000,000
Minimum Margin of Solvency	$ 8,000,000
Minimum Margin of Solvency, percentage of assets of the first threshold	2.00%
Minimum Margin of Solvency, assets threshold	$ 500,000,000
Minimum Margin of Solvency, Percentage of assets in excess of threshold	1.50%
Minimum Margin of Solvency, Percentage of Enhanced Capital Requirement	25.00%
Dividends declared	$ 0	0
Bermuda Insurance Act, maximum percentage of statutory capital and surplus allowed to be paid in dividends	25.00%
Bermuda Insurance Act, maximum percentage of reduction in total statutory capital allowed without prior regulatory approval	15.00%
Aflac
Statutory Accounting Practices [Line Items]
Maximum percentage of statutory capital and surplus in dividends that can be paid to Parent Company	10.00%
Dividends declared	$ 906,000,000	976,000,000
Amount available for dividend distribution without prior approval from regulatory agency	$ 664,000,000
CAIC
Statutory Accounting Practices [Line Items]
Maximum percentage of statutory capital and surplus in dividends that can be paid to Parent Company	10.00%
Dividends declared		0
Extraordinary distribution	$ 240,000,000
TOIC
Statutory Accounting Practices [Line Items]
Maximum percentage of statutory capital and surplus in dividends that can be paid to Parent Company	10.00%
Dividends declared	$ 0	0
Aflac New York
Statutory Accounting Practices [Line Items]
Dividends declared	46,000,000	54,000,000
Aflac Japan
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	$ 6,900,000,000	$ 8,100,000,000