SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Common Stock Issued [Roll Forward]
Balance, beginning of period	671,249	669,723	668,132
Exercise of stock options and issuance of restricted shares	1,632	1,526	1,591
Balance, end of period	672,881	671,249	669,723
Treasury Stock [Roll Forward]
Balance, beginning of period	265,439	245,343	225,687
Exercise of stock options	(2,883)	(2,061)	(2,013)
Balance, end of period	282,426	265,439	245,343
Shares outstanding, end of period	390,455	405,810	424,380
Treasury Stock
Treasury Stock [Roll Forward]
Stock Acquired In Open Market, Shares	17,755	21,618	21,179
Other purchases	509	330	247
Shares issued to AFL Stock Plan	(891)	(1,064)	(1,209)
Exercise of stock options	(367)	(683)	(465)
Other dispositions	(19)	(105)	(96)