Reconciliation of the Number of Shares of Common Stock (Detail) In Thousands				9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Sep. 30, 2011 Common Stock	Sep. 30, 2010 Common Stock	Sep. 30, 2011 Treasury Stock	Sep. 30, 2010 Treasury Stock
Stockholders Equity Note [Line Items]
Balance, beginning of period	663,478	662,660		662,660	661,209
Exercise of stock options and issuance of restricted shares				818	902
Balance, end of period	663,478	662,660		663,478	662,111
Balance, beginning of period						192,999	192,641
Purchases of treasury stock:
Open market						5,100	0
Other						157	98
Dispositions of treasury stock:
Shares issued to AFL Stock Plan						(1,253)	0
Exercise of stock options						(85)	(1,589)
Other						(79)	(83)
Balance, end of period						196,839	191,067
Shares outstanding, end of period	466,639		471,044