Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 250

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6801783&loc=d3e22583-107794

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

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accounting Change

-URI http://asc.fasb.org/extlink&oid=6503790

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 154

-Paragraph 2, 17, 18

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Retrospective Application

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Indirect Effects of a Change in Accounting Principle

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Direct Effects of a Change in Accounting Principle

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-Publisher FASB

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+ Details

- Definition

Tax effect, net of reclassification adjustments, of the change in the balance sheet adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency of the reporting entity. Also includes the following: gain (loss) on foreign currency forward exchange contracts; foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; and gain (loss) on a derivative instrument or nonderivative financial instrument that may give rise to a foreign currency transaction gain (loss) that has been designated and qualified as a hedging instrument for hedging of the foreign currency exposure of a net investment in a foreign operation.

+ References+ Details

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified		9 Months Ended					3 Months Ended		9 Months Ended
	Dec. 31, 2010 Accounting Standards Update 2010-26	Sep. 30, 2012 Aflac Japan	Sep. 30, 2011 Aflac Japan	Dec. 31, 2011 Aflac Japan	Dec. 31, 2010 Retained earnings: Accounting Standards Update 2010-26	Dec. 31, 2010 Accumulated Other Comprehensive Income (Loss) Accounting Standards Update 2010-26	Sep. 30, 2012 Dollar denominated investment portfolio Aflac Japan	Sep. 30, 2011 Dollar denominated investment portfolio Aflac Japan	Sep. 30, 2012 Dollar denominated investment portfolio Aflac Japan	Sep. 30, 2011 Dollar denominated investment portfolio Aflac Japan
Significant Accounting Policies [Line Items]
Aflac Japan's percentage of the Company's total revenues		78.00%	75.00%
Aflac Japan's percentage of the Company's total assets		88.00%		87.00%
Other comprehensive income foreign exchange gains or losses, deferred tax expense (benefit)							$ (86)	$ (186)	$ (25)	$ (236)
Effective income tax rate excluding income tax expense (benefit) related to Aflac Japan's dollar-denominated portfolio							34.40%	29.20%	35.20%	36.50%
Adjustment to the shareholders' equity upon adoption of new DAC accounting guidance	$ (516)				$ (408)	$ (108)