BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014 segment		Jun. 30, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of Reportable Insurance Business Segments				2
Net earned premiums	$ 4,888		$ 5,013	$ 9,742		$ 10,197
Net investment income	843		813	1,670		1,646
Other income	5		17	10		52
Total revenues	5,838		6,044	11,478		12,252
Other non-operating income (loss)	(11)		0	(20)		0
Realized investment gains (losses), non-operating	92	[1]	201	36	[1]	357
Gain (loss) on change in fair value of derivative, interest rate component, operating	10			20
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	3,578		3,717	7,138		7,622
Net investment income	680		653	1,343		1,327
Other income	8		12	17		38
Total revenues	4,266		4,382	8,498		8,987
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	1,311		1,295	2,605		2,575
Net investment income	161		158	322		314
Other income	1		1	1		4
Total revenues	1,473		1,454	2,928		2,893
Other business segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	10		14	20		26
Total Business Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	5,749		5,850	11,446		11,906
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	74		66	152		159
Intercompany eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	$ (66)		$ (73)	$ (136)		$ (170)

[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