SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,349,309	1,347,540
Exercise of stock options and issuance of restricted shares	1,546	1,650
Balance, end of period	1,350,855	1,349,190
Treasury Stock [Roll Forward]
Balance, beginning of period	622,516	592,254
Balance, end of period	647,281	614,060
Shares outstanding, end of period	703,574	735,130
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired under share repurchase program, shares	26,108	23,126
Other purchases	541	589
Shares issued to AFL Stock Plan	(1,584)	(1,232)
Exercise of stock options	(49)	(382)
Other dispositions	(251)	(295)