SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,345,762	1,342,498	1,339,446
Exercise of stock options and issuance of restricted shares	1,778	3,264	3,052
Balance, end of period	1,347,540	1,345,762	1,342,498
Treasury Stock [Roll Forward]
Balance, beginning of period	564,852	530,877	490,686
Exercise of stock options	(1,874)	(5,766)	(4,122)
Balance, end of period	592,254	564,852	530,877
Shares outstanding, end of period	755,286	780,910	811,621
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired in open market, shares	28,949	35,510	43,236
Other purchases	392	1,018	662
Shares issued to AFL Stock Plan	(1,306)	(1,782)	(2,130)
Exercise of stock options	(519)	(734)	(1,366)
Other dispositions	(114)	(37)	(211)