Schedule II - Aflac Incorporated (Parent Only) - Condensed Statement of Earnings (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements, [Line Items]
Net investment income		$ 3,656	$ 3,818	$ 3,638
Net investment gains (losses)		363	468	(270)
Total revenues		19,502	22,106	22,147
Interest expense		226	238	242
Total acquisition and operating expenses		5,745	6,208	6,192
Income tax expense (benefit)		403	997	(619)
Net earnings		4,201	4,325	4,778
Expense on extinguishment of debt			48	15
Parent Company
Condensed Income Statements, [Line Items]
Management and service fees from subsidiaries	[1]	136	130	131
Net investment income		3	(93)	62
Interest from subsidiaries	[1]	2	2	3
Net investment gains (losses)		(228)	206	399
Total revenues		(87)	245	595
Interest expense		215	222	221
Other operating expenses	[2]	275	300	277
Total acquisition and operating expenses		490	522	498
Earnings before income taxes and equity in earnings of subsidiaries		(577)	(277)	97
Income tax expense (benefit)		(208)	(144)	(15)
Earnings before equity in earnings of subsidiaries		(369)	(133)	112
Equity in earnings of subsidiaries	[1]	4,570	4,458	4,666
Net earnings		$ 4,201	4,325	4,778
Expense on extinguishment of debt			$ 48	$ 15

[1] Eliminated in consolidation

[2] Includes expense of $48 in 2021 and $15 in 2020 for the early extinguishment of debt