Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net earnings		$ 5,443	$ 4,659	$ 4,418
Adjustments to reconcile net earnings to net cash provided from operating activities:
Other, net		(616)	1,043	(136)
Net cash provided (used) by operating activities		2,707	3,190	3,879
Cash flows from investing activities:
Fixed maturity securities purchased		(5,542)	(2,801)	(3,514)
Other investments sold (purchased)		(972)	(417)	(227)
Settlement of derivatives		(184)	79	(61)
Other, net		61	(149)	112
Net cash provided (used) by investing activities		2,781	817	(1,540)
Cash flows from financing activities:
Purchases of treasury stock		(2,800)	(2,801)	(2,401)
Proceeds from borrowings		823	204	1,277
Principal payments under debt obligations		(194)	0	(1,416)
Dividends paid to shareholders		(1,087)	(966)	(979)
Treasury stock reissued		14	17	17
Proceeds from exercise of stock options		13	16	16
Other, net		(28)	(17)	34
Net cash provided (used) by financing activities		(3,486)	(3,723)	(3,551)
Net change in cash and cash equivalents		1,923	363	(1,108)
Cash and cash equivalents, beginning of period		4,306
Cash and cash equivalents, end of period		6,229	4,306
Parent Company
Cash flows from operating activities:
Net earnings		5,443	4,659	4,418
Adjustments to reconcile net earnings to net cash provided from operating activities:
Equity in earnings of subsidiaries	[1]	(5,090)	(4,418)	(4,787)
Cash dividends received from subsidiaries		4,274	3,410	2,705
Other, net		(292)	(686)	18
Net cash provided (used) by operating activities		4,335	2,965	2,354
Cash flows from investing activities:
Fixed maturity securities sold		572	547	392
Fixed maturity securities purchased		(695)	(345)	(438)
Other investments sold (purchased)		(243)	(34)	(206)
Settlement of derivatives		469	693	718
Additional capitalization of subsidiaries	[1]	(84)	(203)	(294)
Other, net		0	1	1
Net cash provided (used) by investing activities		19	659	173
Cash flows from financing activities:
Purchases of treasury stock		(2,800)	(2,801)	(2,401)
Proceeds from borrowings		823	0	1,277
Principal payments under debt obligations		0	0	(1,416)
Dividends paid to shareholders		(1,087)	(966)	(979)
Treasury stock reissued		14	17	17
Proceeds from exercise of stock options		9	13	12
Net change in amount due to/from subsidiary	[1]	(5)	(6)	16
Other, net		(7)	(17)	(7)
Net cash provided (used) by financing activities		(3,053)	(3,760)	(3,481)
Net change in cash and cash equivalents		1,301	(136)	(954)
Cash and cash equivalents, beginning of period		1,007	1,143	2,097
Cash and cash equivalents, end of period		$ 2,308	$ 1,007	$ 1,143

[1] Eliminated in consolidation