Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Condensed Financial Statements, Captions [Line Items]
Net earnings	$ 3,646	$ 5,443	$ 4,659
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	146	(769)	(366)
Unrealized holding gains (losses) on fixed maturity securities during period	(2,316)	(1,224)	2,493
Unrealized gains (losses) on derivatives during period	8	3	6
Effect of changes in discount rate assumptions during period	7,631	5,780	(582)
Pension liability adjustment during period	97	23	35
Total other comprehensive income (loss) before income taxes	5,560	3,616	1,420
Income tax expense (benefit) related to items of other comprehensive income (loss)	1,130	1,074	511
Other comprehensive income (loss), net of income taxes	4,430	2,542	909
Total comprehensive income (loss)	8,076	7,985	5,568
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net earnings	3,646	5,443	4,659
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	146	(769)	(366)
Unrealized holding gains (losses) on fixed maturity securities during period	(2,322)	(1,421)	2,327
Unrealized gains (losses) on derivatives during period	8	3	6
Effect of changes in discount rate assumptions during period	7,631	5,780	(582)
Pension liability adjustment during period	97	23	35
Total other comprehensive income (loss) before income taxes	5,560	3,616	1,420
Income tax expense (benefit) related to items of other comprehensive income (loss)	1,130	1,074	511
Other comprehensive income (loss), net of income taxes	4,430	2,542	909
Total comprehensive income (loss)	$ 8,076	$ 7,985	$ 5,568