BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 segment		Mar. 31, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of Reportable Insurance Business Segments	2
Net earned premiums	$ 4,854		$ 5,184
Net investment income	827		833
Other income	5		35
Total revenues	5,640		6,208
Other non-operating income (loss)	(9)		0
Realized investment gains (losses), non-operating	(56)	[1]
Realized investment gains (losses)	(46)		156
Gain (loss) on change in fair value of derivative, interest rate component, operating	10
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	3,560		3,905
Net investment income	663		674
Other income	8		26
Total revenues	4,231		4,605
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	1,294		1,280
Net investment income	161		157
Other income	0		1
Total revenues	1,455		1,438
Other business segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	12		12
Total Business Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	5,698		6,055
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	78		92
Intercompany eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	$ (71)		$ (95)

[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