DERIVATIVE INSTRUMENTS - Additional Information (Detail)			3 Months Ended		6 Months Ended												3 Months Ended		6 Months Ended
	Jun. 30, 2013 USD ($) Y currency counterparties	Dec. 31, 2012 USD ($)	Jun. 30, 2013 Cash flow hedges USD ($)	Jun. 30, 2012 Cash flow hedges USD ($)	Jun. 30, 2013 Cash flow hedges USD ($)	Jun. 30, 2012 Cash flow hedges USD ($)	Jun. 30, 2013 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Dec. 31, 2012 Variable interest rate yen-denominated Samurai notes due July 2014 JPY (¥)	Jun. 30, 2013 3.625% senior notes due June 2023 USD ($)	Jun. 30, 2013 2.65% senior notes due February 2017 USD ($)	Jun. 30, 2013 4.00% senior notes due February 2022 USD ($)	Jun. 30, 2013 5.50% subordinated notes due September 2052 USD ($)	Jun. 30, 2013 Twenty thirteen profit repatriation Foreign currency forwards and options JPY (¥)	Jun. 30, 2013 Twenty fourteen profit repatriation Foreign currency forwards and options JPY (¥)	Jun. 30, 2013 Parent Company USD ($)	Jun. 30, 2013 Aflac USD ($)	Jun. 30, 2013 Non-derivative hedging instruments USD ($)	Jun. 30, 2012 Non-derivative hedging instruments USD ($)	Jun. 30, 2013 Non-derivative hedging instruments USD ($)	Jun. 30, 2012 Non-derivative hedging instruments USD ($)	Jun. 30, 2013 Non-derivative hedging instruments Foreign currency options USD ($)	Jun. 30, 2013 Non-derivative hedging instruments Foreign currency swaps USD ($)
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Number of currencies related to foreign currency swaps	2
Number of counterparties	13
Number of counterparties that comprise majority of aggregate notional amount of swaps	4
Percentage of notional amount of swaps from certain number of counterparties	72.00%
Derivative, Net Liability Position, Aggregate Fair Value															$ 18,000,000	$ 8,000,000
Collateral Already Posted, Aggregate Fair Value															10,000,000	14,000,000
Additional Collateral, Aggregate Fair Value															8,000,000	0
Hedging activity, weighted-average period (in years)	13
Notes payable, principal amount							5,500,000,000	5,500,000,000	700,000,000
Notes payable, effective interest rate							1.475%		1.50%
Derivative, amount of hedged item									700,000,000	400,000,000	350,000,000	500,000,000
Notional Amount of Derivatives	20,413,000,000	13,370,000,000											65,000,000,000	47,500,000,000			3,497,000,000		3,497,000,000		913,000,000	1,950,000,000
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0	0	0	0
Net investment hedge gain loss reclassified to earnings net																	$ 0	$ 0	$ 0	$ 0