CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]
Cash Acquired from Acquisition		$ 9,709
Payments of Debt Issuance Costs	0	3,400
Repayments of Long-term Debt	(192)	0
Cash Flows from Operating Activities:
Net income	492,956	273,878
Change in operating assets and liabilities:
Accrued investment income	(41,658)	(63,339)
Premiums receivable and other reinsurance balances	(74,089)	81,189
Deferred policy acquisition costs	185,107	56,286
Reinsurance ceded receivable balances	9,961	49,286
Future policy benefits, other policy claims and benefits, and other reinsurance balances	736,169	1,005,756
Deferred income taxes	43,670	276,372
Other assets and other liabilities, net	134,471	(293,106)
Amortization of net investment premiums, discounts and other	(80,188)	(70,687)
Investment related gains, net	(225,416)	(66,149)
Gain on repurchase of collateral finance facility securities	0	(46,506)
Excess tax benefits from share-based payment arrangement	3,088	(2,410)
Other, net	54,105	50,460
Net cash provided by operating activities	1,238,176	1,251,030
Cash Flows from Investing Activities:
Sales of fixed maturity securities available-for-sale	3,370,036	2,838,099
Maturities of fixed maturity securities available-for-sale	353,554	118,951
Purchases of fixed maturity securities available-for-sale	(4,414,097)	(3,496,639)
Cash invested in mortgage loans on real estate	(480,906)	(467,429)
Cash invested in policy loans	(52,914)	0
Cash invested in funds withheld at interest	(67,024)	(70,753)
Principal payments on mortgage loans on real estate	341,989	262,226
Principal payments on policy loans	47,435	33,314
Purchase of a business net of cash acquired of $9,709	0	(2,805)
Payments to Acquire Property, Plant, and Equipment	(74,342)	0
Increase (Decrease) in Payables under Repurchase Agreements	100,000	0
Change in short-term investments	93,116	235,260
Change in other invested assets	266,389	35,341
Net cash used in investing activities	(516,764)	(514,435)
Cash Flows from Financing Activities:
Dividends to stockholders	(64,587)	(56,465)
Repurchase and repayment of collateral finance facility securities	0	(119,255)
Repayments of Short-term Debt	0	0
Purchases of treasury stock	(201,032)	(269,204)
Excess tax benefits from share-based payment arrangement	(3,088)	2,410
Exercise of stock options, net	17,010	9,212
Change in cash collateral for derivatives and other arrangements	83,283	(68,635)
Deposits on universal life and other investment type policies and contracts	84,036	120,250
Withdrawals on universal life and other investment type policies and contracts	(525,217)	(550,122)
Net cash used in financing activities	(509,787)	(536,717)
Proceeds from Issuance of Long-term Debt	100,000	398,492
Effect of exchange rate changes on cash	(16,527)	(36,535)
Change in cash and cash equivalents	195,098	163,343
Cash and cash equivalents, beginning of period	923,647	1,259,892
Cash and cash equivalents, end of period	1,118,745	1,423,235
Supplementary information:
Cash paid for interest	93,698	75,003
Cash paid for income taxes, net of refunds	$ 37,833	$ 100,429