Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Financial Statements, Captions [Line Items]
Net earnings	$ 4,201	$ 4,325	$ 4,778
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	(1,080)	(889)	510
Unrealized gains (losses) on derivatives during period	4	5	(1)
Pension liability adjustment during period	165	148	(7)
Total other comprehensive income (loss) before income taxes	(13,967)	(1,696)	1,722
Income tax expense (benefit) related to items of other comprehensive income (loss)	(2,169)	(155)	251
Other comprehensive income (loss), net of tax	(11,798)	(1,541)	1,471
Total comprehensive income (loss)	(7,597)	2,784	6,249
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net earnings	4,201	4,325	4,778
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	(1,080)	(889)	510
Unrealized gains (losses) on fixed maturity securities during period	(13,056)	(960)	1,220
Unrealized gains (losses) on derivatives during period	4	5	(1)
Pension liability adjustment during period	165	148	(7)
Total other comprehensive income (loss) before income taxes	(13,967)	(1,696)	1,722
Income tax expense (benefit) related to items of other comprehensive income (loss)	(2,169)	(155)	251
Other comprehensive income (loss), net of tax	(11,798)	(1,541)	1,471
Total comprehensive income (loss)	$ (7,597)	$ 2,784	$ 6,249