STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Additional Information (Detail) $ in Millions, ¥ in Billions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 JPY (¥)
Statutory Accounting Practices [Line Items]
Statutory accounting practices, statutory capital and surplus required	$ 1,300
Net Derivatives Notional Amount	22,127	$ 23,662
Aflac
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	11,298	10,839
Net Income, Nebraska state basis	2,300	2,400	$ 2,400
Amount available for dividend distribution without prior approval from regulatory agency	2,300
Dividends declared	2,400
Aflac Japan
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	4,700	$ 5,600
Twenty Fifteen Profit Repatriation
Statutory Accounting Practices [Line Items]
Intercompany transfer profit repatriation additional amount received	$ 71
Foreign currency forwards and options | Twenty Fifteen Profit Repatriation
Statutory Accounting Practices [Line Items]
Net Derivatives Notional Amount | ¥				¥ 242.5
Foreign currency forwards and options | Future profit repatriation
Statutory Accounting Practices [Line Items]
Net Derivatives Notional Amount | ¥				¥ 124.1