Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Financial Statements, Captions [Line Items]
Net earnings	$ 5,443	$ 4,659	$ 4,418
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	(769)	(366)	(1,034)
Unrealized holding gains (losses) on fixed maturity securities during period	(1,224)	2,493	(12,603)
Unrealized gains (losses) on derivatives during period	3	6	4
Effect of changes in discount rate assumptions during period	5,780	(582)	17,384
Pension liability adjustment during period	23	35	165
Total other comprehensive income (loss) before income taxes	3,616	1,420	3,463
Income tax expense (benefit) related to items of other comprehensive income (loss)	1,074	511	1,481
Other comprehensive income (loss), net of tax	2,542	909	1,982
Total comprehensive income (loss)	7,985	5,568	6,400
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net earnings	5,443	4,659	4,418
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	(769)	(366)	(1,034)
Unrealized holding gains (losses) on fixed maturity securities during period	(1,421)	2,327	(13,056)
Unrealized gains (losses) on derivatives during period	3	6	4
Effect of changes in discount rate assumptions during period	5,780	(582)	17,384
Pension liability adjustment during period	23	35	165
Total other comprehensive income (loss) before income taxes	3,616	1,420	3,463
Income tax expense (benefit) related to items of other comprehensive income (loss)	1,074	511	1,481
Other comprehensive income (loss), net of tax	2,542	909	1,982
Total comprehensive income (loss)	$ 7,985	$ 5,568	$ 6,400