INVESTMENTS - Securities Lending (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Investments [Abstract]
Securities loaned total	$ 202	$ 6,122
Cash collateral on loaned securities	$ 207	$ 6,277

Amount of obligation to return cash collateral under master netting arrangements that has not been offset against securities loaned.

No definition available.

Name:	afl_SecuritiesLoanedCollateralObligationToReturnCash
Namespace Prefix:	afl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant