Schedule of Analysis Deferred Acquisition Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Acquisition Costs, Balance at beginning of year				$ 2,916,732	[1]	$ 2,869,546	[2]
Deferred Acquisition Costs, Commissions				230,565		212,258	[2]
Deferred Acquisition Costs, Other expenses				124,738		116,792	[2]
Deferred Acquisition Costs, Total deferred costs				355,303		329,050	[2]
Deferred Acquisition Costs, Adjustment attributable to unrealized investment losses				5,353	[3]	0	[2],[3]
Deferred Acquisition Costs, Foreign exchange adjustment				4,471		0	[2]
Deferred Acquisition Costs, Total additions				365,127		329,050	[2]
Deferred Acquisition Costs, Amortized during period	(94,016)	(89,899)	[4]	(287,115)		(274,026)	[2],[4],[5]
Deferred Acquisition Costs, Adjustment attributable to unrealized investment gains				0	[3]	(37,048)	[2],[3]
Deferred Acquisition Costs, Foreign exchange adjustment				0		(2,243)	[2]
Deferred Acquisition Costs, Total deductions						(313,317)	[2]
Deferred Acquisition Costs, Balance at end of period	$ 2,994,744	$ 2,885,279	[2]	$ 2,994,744		$ 2,885,279	[2]

[1] Derived from audited financial statements. Additionally, 2011 balances have been retrospectively adjusted to give effect to the adoption of new accounting guidance as described in Note F-Adoption of New Accounting Standard.

[2] The 2011 balances have been retroactively adjusted to give effect to the adoption of the new accounting guidance.

[3] Represents amounts pertaining to investments relating to universal life-type products.

[4] The 2011 balances have been retrospectively adjusted to give effect to the adoption of new accounting guidance as described in Note F-Adoption of New Accounting Standard.

[5] The 2011 balances have been retroactively adjusted to give effect to the adoption of new accounting guidance as described in Note F-Adoption of New Accounting Standard.