Schedule II - Aflac Incorporated (Parent Only) - Condensed Statement of Earnings (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Condensed Income Statements, [Line Items]
Management and service fees from subsidiaries		$ 112	$ 100	$ 177
Net investment income		4,076	4,116	3,811
Net investment gains (losses)		(572)	1,271	590
Total revenues		17,164	18,927	18,701
Interest expense		220	197	195
Total acquisition and operating expenses		5,338	5,060	5,228
Income tax expense (benefit)		887	974	603
Net earnings		3,646	5,443	4,659
Parent Company
Condensed Income Statements, [Line Items]
Management and service fees from subsidiaries	[1]	170	163	151
Net investment income		147	31	(174)
Interest from subsidiaries	[1]	1	1	1
Net investment gains (losses)		122	503	301
Total revenues		440	698	279
Interest expense		213	189	187
Other operating expenses		392	282	295
Total acquisition and operating expenses		605	471	482
Earnings before income taxes and equity in earnings of subsidiaries		(165)	227	(203)
Income tax expense (benefit)		(103)	(126)	(444)
Earnings before equity in earnings of subsidiaries		(62)	353	241
Equity in earnings of subsidiaries	[1]	3,708	5,090	4,418
Net earnings		$ 3,646	$ 5,443	$ 4,659

[1] Eliminated in consolidation