BUSINESS SEGMENT AND FOREIGN INFORMATION - Operations by Segment - Pretax Earnings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									$ 4,399		$ 4,658	$ 4,502
Realized investment gains (losses), non-operating									389	[1],[2]
Realized investment gains (losses)									399		(349)	(1,552)
Other non-operating income (loss)									28		(7)	0
Earnings before income taxes	1,028	1,069	1,358	1,361	880	1,480	741	1,202	4,816		4,302	2,950
Income taxes applicable to pretax operating earnings									1,512		1,561	1,556
Effect of foreign currency translation on operating earnings									(357)		8	169
Gain (loss) on change in fair value of derivative, interest rate component, operating									10
Aflac Japan
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									3,628		3,904	3,829
Aflac U.S.
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									1,038		997	904
Other business segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									(1)		(3)	1
Total Business Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									4,665		4,898	4,734
Interest expense, noninsurance operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									(198)		(184)	(168)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings									$ (68)		$ (56)	$ (64)

[1] Excluding a gain of $10 in 2013 related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations

[2] (1) Excluding a gain of $10 in 2013 related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations Amounts prior to 2012 have been adjusted for the adoption of accounting guidance on January 1, 2012 related to deferred policy acquisition costs.