SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,345,762	1,342,498
Exercise of stock options and issuance of restricted shares	1,614	2,840
Balance, end of period	1,347,376	1,345,338
Treasury Stock [Roll Forward]
Balance, beginning of period	564,852	530,877
Balance, end of period	584,263	557,588
Shares outstanding, end of period	763,113	787,750
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired in open market, shares	20,443	27,796
Other purchases	361	872
Shares issued to AFL Stock Plan	(850)	(1,392)
Exercise of stock options	(430)	(526)
Other dispositions	(113)	(39)