Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net earnings		$ 3,646	$ 5,443	$ 4,659
Adjustments to reconcile net earnings to net cash provided from operating activities:
Other, net		(273)	(616)	1,043
Net cash provided (used) by operating activities		2,555	2,707	3,190
Cash flows from investing activities:
Fixed maturity securities purchased		(11,742)	(5,542)	(2,801)
Other investments sold (purchased)		(256)	(972)	(417)
Settlement of derivatives		(20)	(184)	79
Other, net		(295)	61	(149)
Net cash provided (used) by investing activities		1,561	2,781	817
Cash flows from financing activities:
Purchases of treasury stock		(3,530)	(2,800)	(2,801)
Proceeds from borrowings		1,039	823	204
Principal payments under debt obligations		(84)	(194)	0
Dividends paid to shareholders		(1,198)	(1,087)	(966)
Treasury stock reissued		8	14	17
Proceeds from exercise of stock options		9	13	16
Other, net		(38)	(28)	(17)
Net cash provided (used) by financing activities		(4,069)	(3,486)	(3,723)
Net change in cash and cash equivalents		16	1,923	363
Cash and cash equivalents, beginning of period		6,229
Cash and cash equivalents, end of period		6,245	6,229
Parent Company
Cash flows from operating activities:
Net earnings		3,646	5,443	4,659
Adjustments to reconcile net earnings to net cash provided from operating activities:
Equity in earnings of subsidiaries	[1]	(3,708)	(5,090)	(4,418)
Cash dividends received from subsidiaries		3,824	4,274	3,410
Other, net		(52)	(292)	(686)
Net cash provided (used) by operating activities		3,710	4,335	2,965
Cash flows from investing activities:
Fixed maturity securities sold		824	572	547
Fixed maturity securities purchased		(772)	(695)	(345)
Other investments sold (purchased)		125	(243)	(34)
Settlement of derivatives		277	469	693
Additional capitalization of subsidiaries	[1]	(15)	(84)	(203)
Other, net		(58)	0	1
Net cash provided (used) by investing activities		381	19	659
Cash flows from financing activities:
Purchases of treasury stock		(3,530)	(2,800)	(2,801)
Proceeds from borrowings		1,039	823	0
Principal payments under debt obligations		(84)	0	0
Dividends paid to shareholders		(1,198)	(1,087)	(966)
Treasury stock reissued		8	14	17
Proceeds from exercise of stock options		7	9	13
Net change in amount due to/from subsidiary	[1]	25	(5)	(6)
Other, net		(20)	(7)	(17)
Net cash provided (used) by financing activities		(3,753)	(3,053)	(3,760)
Net change in cash and cash equivalents		338	1,301	(136)
Cash and cash equivalents, beginning of period		2,308	1,007	1,143
Cash and cash equivalents, end of period		$ 2,646	$ 2,308	$ 1,007

[1] Eliminated in consolidation