Schedule II - Aflac Incorporated (Parent Only) - Condensed Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Investments and cash:
Other investments	$ 463		$ 174
Cash and cash equivalents	2,543		2,041		2,249	2,121
Total investments and cash	108,459		118,219
Other assets	1,606	[1]	835	[1]
Total assets	121,307		131,094		116,237
Liabilities:
Income taxes	3,718		3,858
Notes payable	4,891		4,343
Other liabilities	2,850	[2]	2,909	[2]
Total liabilities	106,687		115,116
Shareholders' equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2013 and 2012; issued 667,046 shares in 2013 and 665,239 shares in 2012	67		67
Additional paid-in capital	1,644		1,505
Retained earnings	19,885		17,387
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains	(1,505)		333
Unrealized gains (losses) on investment securities	1,035		2,570
Unrealized gains (losses) on derivatives	(12)		(5)
Pension liability adjustment	(81)		(183)
Treasury stock, at average cost	(6,413)		(5,696)
Total shareholders' equity	14,620		15,978		12,946
Total liabilities and shareholders' equity	121,307		131,094
Parent Company
Investments and cash:
Fixed maturity securities available for sale, at fair value (amortized cost $322 in 2013 and $131 in 2012)	332		156
Investments in subsidiaries	17,678	[3]	19,001	[3]
Other investments	313		14
Cash and cash equivalents	1,081		830		385	693
Total investments and cash	19,404		20,001
Due from subsidiaries	128	[3]	156	[3]
Other assets	464		257
Total assets	19,996		20,414
Liabilities:
Income taxes	(120)		(232)
Employee benefit plans	246		255
Notes payable	4,910		4,367
Other liabilities	340		46
Total liabilities	5,376		4,436
Shareholders' equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2013 and 2012; issued 667,046 shares in 2013 and 665,239 shares in 2012	67		67
Additional paid-in capital	1,644		1,505
Retained earnings	19,885		17,387
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains	(1,505)		333
Unrealized gains (losses) on investment securities	1,035		2,570
Unrealized gains (losses) on derivatives	(12)		(5)
Pension liability adjustment	(81)		(183)
Treasury stock, at average cost	(6,413)		(5,696)
Total shareholders' equity	14,620		15,978
Total liabilities and shareholders' equity	$ 19,996		$ 20,414

[1] Includes $106 in 2013 and $191 in 2012 of derivatives from consolidated variable interest entities

[2] Includes $207 in 2013 and $399 in 2012 of derivatives from consolidated variable interest entities

[3] Eliminated in consolidation