SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,351,018	1,349,309
Exercise of stock options and issuance of restricted shares	1,261	1,341
Balance, end of period	1,352,279	1,350,650
Treasury Stock [Roll Forward]
Balance, beginning of period	658,564	622,516
Balance, end of period	671,572	632,268
Shares outstanding, end of period	680,707	718,382
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired under share repurchase program, shares	13,440	9,984
Other purchases	378	508
Shares issued to AFL Stock Plan	(387)	(468)
Exercise of stock options	(211)	(45)
Other dispositions	(212)	(227)