BENEFIT PLANS - Fair Value Hierarchy Levels of Funded Pension Plans' Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Japanese Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 182	$ 187	$ 171
Japanese Pension Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	182	187
Japanese Pension Plan | Level 2 | Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0	15
Japanese Pension Plan | Level 2 | International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	34	42
Japanese Pension Plan | Level 2 | Japanese Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	60	62
Japanese Pension Plan | Level 2 | International Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	43	44
Japanese Pension Plan | Level 2 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	21	0
Japanese Pension Plan | Level 2 | Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	24	24
U.S. Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	313	261	224
U.S. Pension Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	313	261
U.S. Pension Plan | Level 1 | US Large Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	110	87
U.S. Pension Plan | Level 1 | US Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	19	16
U.S. Pension Plan | Level 1 | Real Estate Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	9	8
U.S. Pension Plan | Level 1 | International Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	68	59
U.S. Pension Plan | Level 1 | Fixed Income Bond Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	103	88
U.S. Pension Plan | Level 1 | Aflac Incorporated Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 4	$ 3