DEFERRED POLICY ACQUISITION COSTS AND INSURANCE EXPENSES - Depreciation and Other Amortization Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Depreciation and Other Amortization Expenses [Line Items]
Depreciation expense	$ 60		$ 59		$ 60
Other amortization expense	7		5		22
Total depreciation and other amortization expense	67	[1]	64	[1]	82	[1]
Aflac Japan
Depreciation and Other Amortization Expenses [Line Items]
Total depreciation and other amortization expense	$ 33		$ 51		$ 48

[1] Aflac Japan accounted for $33 in 2012, $51 in 2011 and $48 in 2010