Schedule II - Aflac Incorporated (Parent Only) - Condensed Statements of Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Net earnings	$ 3,158	$ 2,866	$ 1,937
Foreign currency translation adjustments:
Unrealized foreign currency translation gains (losses) during period - parent only	(1,588)	(287)	(18)
Unrealized gains (losses) on investment securities:
Unrealized holding gains (losses) on investment securities during period - parent only	(2,362)	1,660	566
Unrealized gains (losses) on derivatives during period	(10)	(22)	(33)
Pension liability adjustment during period	157	(20)	(65)
Total other comprehensive income (loss) before income taxes	(3,859)	1,828	1,604
Income tax expense (benefit) related to items of other comprehensive income (loss)	(581)	1,078	392
Other comprehensive income (loss), net of income taxes	(3,278)	750	1,212
Total comprehensive income (loss)	(120)	3,616	3,149
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net earnings	3,158	2,866	1,937
Foreign currency translation adjustments:
Unrealized foreign currency translation gains (losses) during period - parent only	48	95	(54)
Equity in unrealized foreign currency translation gains (losses) of subsidiaries during period	(1,636)	(382)	36
Unrealized gains (losses) on investment securities:
Unrealized holding gains (losses) on investment securities during period - parent only	(12)	15	11
Equity in unrealized holding gains (losses) on investment securities held by subsidiaries during period	(2,350)	1,645	555
Equity in reclassification adjustment for realized (gains) losses of subsidiaries included in net earnings	(56)	497	1,154
Unrealized gains (losses) on derivatives during period	(10)	(22)	(33)
Pension liability adjustment during period	157	(20)	(65)
Total other comprehensive income (loss) before income taxes	(3,859)	1,828	1,604
Income tax expense (benefit) related to items of other comprehensive income (loss)	(581)	1,078	392
Other comprehensive income (loss), net of income taxes	(3,278)	750	1,212
Total comprehensive income (loss)	$ (120)	$ 3,616	$ 3,149