Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net cash provided by operating activities	$ 298,843	$ 112,280
Proceeds from sales, maturities and redemptions of investments:
Fixed maturities, available-for-sale	3,024,890	2,648,898
Mortgage loans on real estate	54,923	40,355
Limited partnership interests, other corporation interests and other investments	1,174	4,574
Purchases of investments:
Fixed maturities, available-for-sale	(1,009,516)	(409,356)
Mortgage loans on real estate	(131,172)	(89,239)
Limited partnership interests, other corporation interests and other investments	(123)	(606)
Net change in short-term investments	(2,170,798)	(2,367,889)
Net change in policy loans	(141)	(18)
Purchases of furniture, equipment and software	(23,451)	(5,365)
Net cash used in investing activities	(254,214)	(178,646)
Cash flows from financing activities:
Contract deposits	428,073us-gaap_AdditionsToContractHoldersFunds	576,724us-gaap_AdditionsToContractHoldersFunds
Contract withdrawals	(401,887)	(436,178)
Net change in due to/from parent and affiliates	16,067	43,388
Dividends paid	(77,309)us-gaap_PaymentsOfDividendsCommonStock	(92,801)us-gaap_PaymentsOfDividendsCommonStock
Payments for and interest (paid) received on financing element derivatives, net	(4,169)	(4,029)
Net change in commercial paper borrowings	(8,600)	(299)
Net change in book overdrafts	(1,722)	(13,020)
Income tax benefit of stock option exercises	275	27
Net cash (used in) provided by financing activities	(49,272)	73,812
Net (decrease) increase in cash	(4,643)	7,446
Cash, beginning of year	12,775	7,491
Cash, end of period	8,132	14,937
Net cash (paid) received during the year for:
Income taxes	(11,488)us-gaap_IncomeTaxesPaidNet	30,969us-gaap_IncomeTaxesPaidNet
Interest	(56)us-gaap_InterestPaid	(68)us-gaap_InterestPaid
Non-cash investing and financing transactions during the years:
Share-based compensation expense	$ 525us-gaap_ShareBasedCompensation	$ 650us-gaap_ShareBasedCompensation

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