SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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	1,060	1,014
Balance, end of period	1,348,600	1,346,776
Treasury Stock [Roll Forward]
Balance, beginning of period	592,254	564,852
Balance, end of period	602,113	571,019
Shares outstanding, end of period	746,487	775,757
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired in open market, shares	10,237	6,640
Other purchases	561	315
Shares issued to AFL Stock Plan	(430)	(384)
Exercise of stock options	(231)	(305)
Other dispositions	(278)	(99)