SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,347,540	1,345,762
Exercise of stock options and issuance of restricted shares	1,650	1,614
Balance, end of period	1,349,190	1,347,376
Treasury Stock [Roll Forward]
Balance, beginning of period	592,254	564,852
Balance, end of period	614,060	584,263
Shares outstanding, end of period	735,130	763,113
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired under share repurchase program, shares	23,126	20,443
Other purchases	589	361
Shares issued to AFL Stock Plan	(1,232)	(850)
Exercise of stock options	(382)	(430)
Other dispositions	(295)	(113)