SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 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	1,341	1,060
Balance, end of period	1,350,650	1,348,600
Treasury Stock [Roll Forward]
Balance, beginning of period	622,516	592,254
Balance, end of period	632,268	602,113
Shares outstanding, end of period	718,382	746,487
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired under share repurchase program, shares	9,984	10,237
Other purchases	508	561
Shares issued to AFL Stock Plan	(468)	(430)
Exercise of stock options	(45)	(231)
Other dispositions	(227)	(278)