Schedule of Contractholder Funds Activity (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Insurance [Line Items]
Balance, beginning of year	$ 14,255,844	$ 15,489,624	$ 17,247,071
Deposits	1,109,108	1,070,374	1,007,316
Interest credited	524,801	406,805	576,331
Benefits	(353,687)	(473,329)	(459,991)
Surrenders and partial withdrawals	(1,880,495)	(1,703,966)	(2,412,295)
Contract charges	(601,609)	(558,519)	(513,068)
Net transfers from separate accounts	18,477	16,463	18,935
Other adjustments	51,676	8,392	25,325
Balance, end of year	$ 13,124,115	$ 14,255,844	$ 15,489,624