BUSINESS SEGMENT AND FOREIGN INFORMATION - Operations by Segment - Revenues (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums	$ 4,910	$ 5,028	$ 5,013	$ 5,184	$ 5,643	$ 5,660	$ 5,467	$ 5,378	$ 20,135		$ 22,148	$ 20,362
Net investment income	826	821	813	833	876	869	845	882	3,293		3,473	3,280
Other income	45	15	17	35	27	32	8	25	112		92	81
Total revenues	5,801	5,886	6,044	6,208	6,375	6,847	5,902	6,240	23,939		25,364	22,171
Realized investment gains (losses), non-operating									389	[1],[2]
Realized investment gains (losses)									399		(349)	(1,552)
Other non-operating income (loss)									28		0	0
Gain (loss) on change in fair value of derivative, interest rate component, operating									10
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									14,982		17,151	15,619
Net investment income									2,651		2,845	2,688
Other income									55		57	46
Total revenues									17,688		20,053	18,353
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									5,153		4,996	4,743
Net investment income									632		613	588
Other income									6		19	10
Total revenues									5,791		5,628	5,341
Other business segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									49		46	54
Total Business Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									23,528		25,727	23,748
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									302		262	241
Intercompany eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									(308)		(276)	(266)
Cancer [Member] | Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									6,123		7,537	7,541
Cancer [Member] | Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									1,283		1,282	1,258
Medical And Other Health [Member] | Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									4,282		5,244	5,158
Life insurance | Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									4,577		4,370	2,920
Life insurance | Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									252		242	230
Accident And Disability [Member] | Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									2,284		2,213	2,194
Other Health [Member] | Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Earned premiums									$ 1,334		$ 1,259	$ 1,061

[1] Excluding a gain of $10 in 2013 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

[2] (1) Excluding a gain of $10 in 2013 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 Amounts prior to 2012 have been adjusted for the adoption of accounting guidance on January 1, 2012 related to deferred policy acquisition costs.