Schedule II - Aflac Incorporated (Parent Only) - Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Shareholder dividend reinvestment
Condensed Cash Flow Statements, Captions [Line Items]
Treasury stock issued for shareholder dividend reinvestment	$ 37	$ 32	$ 29
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
Interest paid	211	213	209
Parent Company | Shareholder dividend reinvestment
Condensed Cash Flow Statements, Captions [Line Items]
Treasury stock issued for shareholder dividend reinvestment	$ 37	$ 32	$ 29