POLICY LIABILITIES - Liability for Future Policy Benefits (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 76,106	$ 69,687
Aflac Japan
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.50%	3.60%	3.80%
Aflac U.S.
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		5.50%	5.60%	5.70%
Intercompany eliminations | 2015
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.00%
Interest Rates In 20 Years		2.00%
Liability amounts	[1]	$ (630)	$ (646)
Health insurance | Aflac Japan | 1992 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 8,912	7,633
Health insurance | Aflac Japan | 1992 - 2016 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		1.25%
Interest Rates In 20 Years		1.25%
Health insurance | Aflac Japan | 1992 - 2016 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.50%
Interest Rates In 20 Years		2.50%
Health insurance | Aflac Japan | 1974 - 2013
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 1,118	1,078
Health insurance | Aflac Japan | 1974 - 2013 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.70%
Interest Rates In 20 Years		2.25%
Health insurance | Aflac Japan | 1974 - 2013 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.75%
Interest Rates In 20 Years		2.75%
Health insurance | Aflac Japan | 1998 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.00%
Interest Rates In 20 Years		3.00%
Liability amounts		$ 11,687	11,008
Health insurance | Aflac Japan | 1997 - 1999
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.50%
Interest Rates In 20 Years		3.50%
Liability amounts		$ 2,485	2,435
Health insurance | Aflac Japan | 1994 - 1996
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 3,069	2,998
Health insurance | Aflac Japan | 1994 - 1996 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		4.00%
Interest Rates In 20 Years		4.00%
Health insurance | Aflac Japan | 1994 - 1996 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		4.50%
Interest Rates In 20 Years		4.50%
Health insurance | Aflac Japan | 1987 - 1994
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		5.50%
Interest Rates In 20 Years		5.50%
Liability amounts		$ 14,372	14,161
Health insurance | Aflac Japan | 1985 - 1991
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 1,871	1,868
Health insurance | Aflac Japan | 1985 - 1991 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		5.25%
Interest Rates In 20 Years		5.25%
Health insurance | Aflac Japan | 1985 - 1991 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		6.75%
Interest Rates In 20 Years		5.50%
Health insurance | Aflac Japan | 1978 - 1984
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		6.50%
Interest Rates In 20 Years		5.50%
Liability amounts		$ 2,134	2,163
Health insurance | Aflac U.S. | 2013 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 75	57
Health insurance | Aflac U.S. | 2013 - 2016 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.00%
Interest Rates In 20 Years		3.00%
Health insurance | Aflac U.S. | 2013 - 2016 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.50%
Interest Rates In 20 Years		3.50%
Health insurance | Aflac U.S. | 2012 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.75%
Interest Rates In 20 Years		3.75%
Liability amounts		$ 1,062	794
Health insurance | Aflac U.S. | 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		4.75%
Interest Rates In 20 Years		4.75%
Liability amounts		$ 319	300
Health insurance | Aflac U.S. | 2005 - 2010
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		5.50%
Interest Rates In 20 Years		5.50%
Liability amounts		$ 3,004	2,986
Health insurance | Aflac U.S. | 1988 - 2004
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		8.00%
Interest Rates In 20 Years		6.00%
Liability amounts		$ 669	687
Health insurance | Aflac U.S. | 1986 - 2004
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		6.00%
Interest Rates In 20 Years		6.00%
Liability amounts		$ 1,265	1,276
Health insurance | Aflac U.S. | 1981 - 1986
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 166	174
Health insurance | Aflac U.S. | 1981 - 1986 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		6.50%
Interest Rates In 20 Years		5.50%
Health insurance | Aflac U.S. | 1981 - 1986 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		7.00%
Interest Rates In 20 Years		6.50%
Health insurance | Aflac U.S. | 1998 - 2004
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		7.00%
Interest Rates In 20 Years		7.00%
Liability amounts		$ 1,295	1,279
Health insurance | Aflac U.S. | Other years
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		19	21
Life insurance | Aflac Japan | 2001 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 7,255	5,441
Life insurance | Aflac Japan | 2001 - 2016 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		1.50%
Interest Rates In 20 Years		1.50%
Life insurance | Aflac Japan | 2001 - 2016 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		1.85%
Interest Rates In 20 Years		1.85%
Life insurance | Aflac Japan | 2011 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.00%
Interest Rates In 20 Years		2.00%
Liability amounts		$ 4,151	3,226
Life insurance | Aflac Japan | 2009 - 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.25%
Interest Rates In 20 Years		2.25%
Liability amounts		$ 2,861	2,332
Life insurance | Aflac Japan | 1992 - 2006
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.19%
Interest Rates In 20 Years		1.55%
Liability amounts		$ 5	5
Life insurance | Aflac Japan | 2005 - 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.50%
Interest Rates In 20 Years		2.50%
Liability amounts		$ 1,488	1,330
Life insurance | Aflac Japan | 1985 - 2006
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.70%
Interest Rates In 20 Years		2.25%
Liability amounts		$ 2,007	1,962
Life insurance | Aflac Japan | 2007 - 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		2.75%
Interest Rates In 20 Years		2.75%
Liability amounts		$ 1,220	1,105
Life insurance | Aflac Japan | 1999 - 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.00%
Interest Rates In 20 Years		3.00%
Liability amounts		$ 2,102	1,988
Life insurance | Aflac Japan | 1996 - 2009
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.50%
Interest Rates In 20 Years		3.50%
Liability amounts		$ 657	635
Life insurance | Aflac Japan | 1994 - 1996
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 897	877
Life insurance | Aflac Japan | 1994 - 1996 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		4.00%
Interest Rates In 20 Years		4.00%
Life insurance | Aflac Japan | 1994 - 1996 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		4.50%
Interest Rates In 20 Years		4.50%
Life insurance | Aflac U.S. | 1956 - 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability amounts		$ 571	$ 514
Life insurance | Aflac U.S. | 1956 - 2016 | Lower Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		3.50%
Interest Rates In 20 Years		3.50%
Life insurance | Aflac U.S. | 1956 - 2016 | Upper Limit
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest Rates Year of Issue		6.00%
Interest Rates In 20 Years		6.00%

[1] Elimination entry necessary due to recapture of a portion of policy liabilities ceded externally, as a result of the reinsurance retrocession transaction as described in Note 8 of the Notes to the Consolidated Financial Statements