Number of Series of Senior Notes Issued Through a U.S. Public Debt Offering

No definition available.

Name:	afl_NumberOfSeriesOfSeniorNotesIssuedThroughUSPublicDebtOffering
Namespace Prefix:	afl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of outstanding long-term debt or borrowing associated with any securities or credit agreement for which there has been a default in principal, interest, sinking fund, or redemption provisions, or any breach of covenant that existed at the end of the period and subsequently has not been cured.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(c))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtDefaultLongtermDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SubordinatedBondsPointNineSixThreePercentDueAprilTwentyFortyNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesPointThreeZeroZeroPercentDueSeptemberTwentyTwentyNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesPointFiveFiveZeroPercentDueMarchTwentyThirtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesPointSevenFiveZeroPercentDueMarchTwentyThirtyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesPointEightThreeZeroPercentDueMarchTwentyThirtyFIveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesFourPointZeroZeroPercentDueFebruaryTwentyTwentyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

NOTES PAYABLE AND LEASE OBLIGATIONS - Additional Information (Details) $ in Millions, ¥ in Billions	1 Months Ended
	Jan. 31, 2020 USD ($)	Mar. 31, 2020 JPY (¥) series	Mar. 31, 2020 USD ($) series	Dec. 31, 2019 JPY (¥)
Debt Instrument [Line Items]
Number of Series of Senior Notes Issued Through a U.S. Public Debt Offering \| series		4	4
Lines of credit
Debt Instrument [Line Items]
Debt instrument, debt default, amount \| $			$ 0
.936% subordinate bond due April 2049
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 30.0		¥ 30.0
Debt instrument, interest rate		0.963%	0.963%	0.963%
Notes payable
Debt Instrument [Line Items]
Debt instrument, debt default, amount \| $			$ 0
Senior notes
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 57.0
.300% senior notes due September 2025
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 12.4
Debt instrument, interest rate		0.30%	0.30%
.550% senior notes due March 2030
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 13.3
Debt instrument, interest rate		0.55%	0.55%
.750% senior notes due March 2032
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 20.7
Debt instrument, interest rate		0.75%	0.75%
.830% senior notes due March 2035
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 10.6
Debt instrument, interest rate		0.83%	0.83%
4.00% senior notes paid January 2020
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%	4.00%	4.00%	4.00%
Repayments of debt \| $	$ 350