Schedule II - Aflac Incorporated - Aggregate Contractual Maturities of Notes Payable (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Condensed Financial Statements, Captions [Line Items]
2018	$ 8
2019	7
2020	553
2021	46
2022	351
Thereafter	4,365
Total	5,330
Parent Company
Condensed Financial Statements, Captions [Line Items]
2018	0
2019	0
2020	550
2021	44
2022	350
Thereafter	4,364
Total	$ 5,308

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
-Paragraph 3
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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