BUSINESS SEGMENT AND FOREIGN INFORMATION - Additional Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014 segment	Dec. 31, 2013
Segment Reporting Information [Line Items]
Reportable insurance business segments	2us-gaap_NumberOfReportableSegments
Total receivables related to Aflac Japan's operations	$ 842us-gaap_PremiumsAndOtherReceivablesNet	$ 1,165us-gaap_PremiumsAndOtherReceivablesNet
Aflac Japan
Segment Reporting Information [Line Items]
Total receivables related to Aflac Japan's operations	$ 386	$ 731
Percentage of total receivables related to Aflac Japan's operations	45.80%	82.90%
Maximum \| Machinery and Equipment [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Maximum \| Building
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Useful Life	50 years
Maximum \| Furniture and fixtures
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Useful Life	20 years

Percentage of the carrying amount, as of the balance sheet date, net of allowance for doubtful accounts, of all premiums and other types of receivables due from other persons or entities.

No definition available.

+ Details

Name:	afl_PercentageOfTotalPremiumsAndOtherReceivablesNet
Namespace Prefix:	afl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of all premiums and other types of receivables due from other persons or entities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.5)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 5

-Article 7

+ Details

Name:	us-gaap_PremiumsAndOtherReceivablesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=afl_AflacJapanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: