Schedule II - Aflac Incorporated (Parent Only) - Condensed Statement of Earnings (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Income Statements, [Line Items]
Management and service fees from subsidiaries		$ 100	$ 177	$ 220
Net investment income		4,116	3,811	3,656
Net investment gains (losses)		1,271	590	363
Total revenues		18,927	18,701	19,140
Total acquisition and operating expenses		5,060	5,228	5,384
Income tax expense (benefit)		974	603	451
Net earnings		5,443	4,659	4,418
Parent Company
Condensed Income Statements, [Line Items]
Management and service fees from subsidiaries	[1]	163	151	136
Net investment income		31	(174)	3
Interest from subsidiaries	[1]	1	1	2
Net investment gains (losses)		503	301	(228)
Total revenues		698	279	(87)
Interest expense		189	187	215
Other operating expenses		282	295	275
Total acquisition and operating expenses		471	482	490
Earnings before income taxes and equity in earnings of subsidiaries		227	(203)	(577)
Income tax expense (benefit)		(126)	(444)	(208)
Earnings before equity in earnings of subsidiaries		353	241	(369)
Equity in earnings of subsidiaries	[1]	5,090	4,418	4,787
Net earnings		$ 5,443	$ 4,659	$ 4,418

[1] Eliminated in consolidation