STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Additional Information (Detail) $ in Millions, ¥ in Billions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 JPY (¥)
Statutory Accounting Practices [Line Items]
Statutory accounting practices, statutory capital and surplus required	$ 1,300
Net Derivatives Notional Amount	43,927	$ 22,127
Aflac
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	11,221	11,298
Net Income, Nebraska state basis	2,800	2,300	$ 2,400
Amount available for dividend distribution without prior approval from regulatory agency	2,800
Dividends declared	2,000
Aflac Japan
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	5,600	$ 4,700
Twenty Sixteen Profit Repatriation
Statutory Accounting Practices [Line Items]
Intercompany transfer profit repatriation, reduction in amount received	$ 64
Foreign currency forwards and options | Twenty Sixteen Profit Repatriation
Statutory Accounting Practices [Line Items]
Net Derivatives Notional Amount | ¥				¥ 114.0
Foreign currency forwards and options | Future profit repatriation
Statutory Accounting Practices [Line Items]
Net Derivatives Notional Amount | ¥				¥ 122.6