POLICY LIABILITIES - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liability for Future Policy Benefit, by Product Segment [Line Items]
Percentage of future policy benefits out of policy liabilities	78.00%
Percentage of unpaid policy claims out of policy liabilities	4.00%
Percentage of unearned premiums out of policy liabilities	11.00%
Percentage of other poliyholders' funds out of policy liabilities	7.00%
Percentage of advanced premiums to unearned premiums	80.00%	82.00%
Percentage of annuities to other policyholders' fund	98.00%	93.00%
Aflac Japan
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average interest rates reflected in the consolidated statements of earnings for future policy benefits	3.80%	3.90%	4.00%
Aflac U.S.
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average interest rates reflected in the consolidated statements of earnings for future policy benefits	5.70%	5.80%	6.00%