Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Cash flows from operating activities:
Net earnings	$ 3,158		$ 2,866		$ 1,937
Adjustments to reconcile net earnings to net cash provided from operating activities:
Change in income tax liabilities	993		712		266
Other, net	401		(138)		165
Net cash provided (used) by operating activities	10,547		14,952		10,842
Cash flows from investing activities:
Fixed maturity securities sold	9,631		7,385		14,385
Fixed maturity securities purchased	(22,967)		(19,533)		(8,392)
Other, net	(354)		514		(62)
Net cash provided (used) by investing activities	(11,091)		(16,952)		(10,829)
Cash flows from financing activities:
Purchases of treasury stock	(813)		(118)		(308)
Proceeds from borrowings	700		1,506		620
Principal payments under debt obligations	0		(341)		(462)
Dividends paid to shareholders	(635)		(603)		(552)
Treasury stock reissued	88		32		26
Net change in amount due to/from subsidiaries	6		12		7
Net cash provided (used) by financing activities	1,136		1,945		64
Net change in cash and cash equivalents	502		(208)		128
Cash and cash equivalents, beginning of period	2,041		2,249		2,121
Cash and cash equivalents, end of period	2,543		2,041		2,249
Parent Company
Cash flows from operating activities:
Net earnings	3,158		2,866		1,937
Adjustments to reconcile net earnings to net cash provided from operating activities:
Equity in undistributed earnings of subsidiaries	(1,986)	[1]	(2,749)	[1]	(1,642)	[1]
Change in income tax liabilities	155		111		(52)
Other, net	11		(242)		145
Net cash provided (used) by operating activities	1,338		(14)		388
Cash flows from investing activities:
Fixed maturity securities sold	8		13		4
Fixed maturity securities purchased	(206)		(26)		(10)
Other investments sold (purchased)	(298)		(3)		0
Additional capitalization of subsidiaries	0	[1]	0	[1]	(40)	[1]
Net cash provided (used) by investing activities	(496)		(16)		(46)
Cash flows from financing activities:
Purchases of treasury stock	(813)		(118)		(308)
Proceeds from borrowings	700		1,506		620
Principal payments under debt obligations	0		(380)		(459)
Dividends paid to shareholders	(635)		(603)		(552)
Treasury stock reissued	88		70		26
Proceeds from exercise of stock options	41		21		14
Net change in amount due to/from subsidiaries	28	[1]	(21)	[1]	9	[1]
Net cash provided (used) by financing activities	(591)		475		(650)
Net change in cash and cash equivalents	251		445		(308)
Cash and cash equivalents, beginning of period	830		385		693
Cash and cash equivalents, end of period	$ 1,081		$ 830		$ 385

[1] Eliminated in consolidation