SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,347,540	1,345,762	1,342,498
Exercise of stock options and issuance of restricted shares	1,769	1,778	3,264
Balance, end of period	1,349,309	1,347,540	1,345,762
Treasury Stock [Roll Forward]
Balance, beginning of period	592,254	564,852	530,877
Exercise of stock options	(1,584)	(1,874)	(5,766)
Balance, end of period	622,516	592,254	564,852
Shares outstanding, end of period	726,793	755,286	780,910
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired under share repurchase program, shares	31,994	28,949	35,510
Other purchases	592	392	1,018
Shares issued to AFL Stock Plan	(1,610)	(1,306)	(1,782)
Exercise of stock options	(418)	(519)	(734)
Other dispositions	(296)	(114)	(37)