BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	$ 1,157		$ 1,157	$ 2,326		$ 2,362
Realized investment gains (losses), non-operating	92	[1]	201	36	[1]	357
Other non-operating income (loss)	(11)		0	(20)		0
Earnings before income taxes	1,238		1,358	2,342		2,719
Income taxes applicable to pretax operating earnings	400		398	795		813
Effect of foreign currency translation on operating earnings	(13)		(103)	(61)		(174)
Gain (loss) on change in fair value of derivative, interest rate component, operating	10			20
Aflac Japan
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	927		940	1,860		1,929
Aflac U.S.
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	300		283	603		564
Total Business Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	1,227		1,223	2,463		2,493
Interest expense, noninsurance operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	(51)		(48)	(101)		(97)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	$ (19)		$ (18)	$ (36)		$ (34)

[1] Excluding a gain of $10 for the three-month period and $20 for the six-month period ended June 30, 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