XML 126 R59.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

INVESTMENTS - Information Regarding Changes in Unrealized Gains and Losses from Investments (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Changes in unrealized gains (losses): |  |  |
Changes in unrealized gains (losses) | $ 5,852 | $ (3,142) | $ 1,728
Fixed maturity securities | Available-for-sale securities |  |  |
Changes in unrealized gains (losses): |  |  |
Changes in unrealized gains (losses) | 5,852 | (3,142) | 1,657
Equity securities |  |  |
Changes in unrealized gains (losses): |  |  |
Changes in unrealized gains (losses) | $ 0 | $ 0 | $ 71

X
- Definition The change in the aggregate increase (decrease) in the market value of unsold investments. + References No definition available. + Details
Name: | afl_ChangesInUnrealizedGainLossOnInvestments
Namespace Prefix: | afl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Changes in Unrealized Gain Loss on Investments [Abstract] + References No definition available. + Details
Name: | afl_ChangesInUnrealizedGainLossOnInvestmentsAbstract
Namespace Prefix: | afl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |