BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	$ 1,169		$ 1,205
Realized investment gains (losses), non-operating	(56)	[1]
Realized investment gains (losses)	(46)		156
Other non-operating income (loss)	(9)		0
Earnings before income taxes	1,104		1,361
Income taxes applicable to pretax operating earnings	395		415
Effect of foreign currency translation on operating earnings	(48)		(71)
Gain (loss) on change in fair value of derivative, interest rate component, operating	10
Aflac Japan
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	933		989
Aflac U.S.
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	303		281
Total Business Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	1,236		1,270
Interest expense, noninsurance operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	(50)		(48)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	$ (17)		$ (17)

[1] Excluding a gain of $10 for the three-month period ended March 31, 2014 related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations