Contractual Maturities of Investments in Fixed Maturities (Detail) (USD $) In Millions	Sep. 30, 2011
Aflac Japan
Available for sale:
Due in one year or less	$ 1,832
Due after one year through five years	3,558
Due after five years through 10 years	3,778
Due after 10 years	29,593
Mortgage- and asset-backed securities	1,268
Total fixed maturities available for sale	40,029
Held to maturity:
Due in one year or less	360
Due after one year through five years	1,301
Due after five years through 10 years	3,590
Due after 10 years	35,962
Mortgage- and asset-backed securities	138
Total fixed maturities held to maturity	41,351
Available for sale:
Due in one year or less	1,873
Due after one year through five years	3,716
Due after five years through 10 years	4,028
Due after 10 years	29,838
Mortgage- and asset-backed securities	1,389
Total fixed maturities available for sale	40,844
Held to maturity:
Due in one year or less	364
Due after one year through five years	1,389
Due after five years through 10 years	3,855
Due after 10 years	34,360
Mortgage- and asset-backed securities	143
Total fixed maturities held to maturity	40,111
Aflac U.S.
Available for sale:
Due in one year or less	36
Due after one year through five years	267
Due after five years through 10 years	897
Due after 10 years	7,485
Mortgage- and asset-backed securities	47
Total fixed maturities available for sale	8,732
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity	0
Available for sale:
Due in one year or less	37
Due after one year through five years	291
Due after five years through 10 years	1,027
Due after 10 years	8,478
Mortgage- and asset-backed securities	59
Total fixed maturities available for sale	9,892
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity	$ 0

This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 7

-Footnote 2

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 20

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682