Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net earnings		$ 4,201	$ 4,325	$ 4,778
Adjustments to reconcile net earnings to net cash provided from operating activities:
Other, net		(162)	(82)	176
Net cash provided (used) by operating activities		3,879	5,051	5,958
Cash flows from investing activities:
Fixed maturity securities purchased		(3,514)	(5,813)	(4,772)
Other investments sold (purchased)		(227)	(1,066)	(860)
Settlement of derivatives		(61)	199	18
Other, net		112	41	(265)
Net cash provided (used) by investing activities		(1,540)	(2,378)	(4,619)
Cash flows from financing activities:
Purchases of treasury stock		(2,401)	(2,301)	(1,537)
Proceeds from borrowings		1,277	1,153	1,545
Principal payments under debt obligations		(1,416)	(700)	(350)
Dividends paid to shareholders		(979)	(855)	(769)
Treasury stock reissued		17	26	34
Proceeds from exercise of stock options		16	26	18
Other, net		34	(26)	(27)
Net cash provided (used) by financing activities		(3,551)	(2,739)	(1,115)
Net change in cash and cash equivalents		(1,108)	(90)	245
Cash and cash equivalents, beginning of period		5,051
Cash and cash equivalents, end of period		3,943	5,051
Parent Company
Cash flows from operating activities:
Net earnings		4,201	4,325	4,778
Adjustments to reconcile net earnings to net cash provided from operating activities:
Equity in earnings of subsidiaries	[1]	(4,570)	(4,458)	(4,666)
Cash dividends received from subsidiaries		2,705	2,791	2,060
Other, net		18	408	(331)
Net cash provided (used) by operating activities		2,354	3,066	1,841
Cash flows from investing activities:
Fixed maturity securities sold		392	483	438
Fixed maturity securities purchased		(438)	(489)	(484)
Other investments sold (purchased)		(206)	(421)	(711)
Settlement of derivatives		718	135	4
Additional capitalization of subsidiaries	[1]	(294)	(161)	(291)
Other, net		1	1	2
Net cash provided (used) by investing activities		173	(452)	(1,042)
Cash flows from financing activities:
Purchases of treasury stock		(2,401)	(2,301)	(1,537)
Proceeds from borrowings		1,277	1,153	1,545
Principal payments under debt obligations		(1,416)	(700)	(350)
Dividends paid to shareholders		(979)	(855)	(769)
Treasury stock reissued		17	26	34
Proceeds from exercise of stock options		12	17	12
Net change in amount due to/from subsidiary	[1]	16	43	(89)
Other, net		(7)	(26)	(27)
Net cash provided (used) by financing activities		(3,481)	(2,643)	(1,181)
Net change in cash and cash equivalents		(954)	(29)	(382)
Cash and cash equivalents, beginning of period		2,097	2,126	2,508
Cash and cash equivalents, end of period		$ 1,143	$ 2,097	$ 2,126

[1] Eliminated in consolidation