Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash provided from operations	$ 771,003	$ 697,668
Long-term investments sold or matured:
Fixed maturities available for sale - sold	78,751	148,597
Fixed maturities available for sale - matured, called, and repaid	453,216	624,815
Equities and other long-term investments	14,067	1,525
Total long-term investments sold or matured	546,034	774,937
Long-term investments acquired:
Fixed maturities	(792,562)	(747,008)
Other long-term investments	(571)	(1,750)
Total long-term investments acquired	(793,133)	(748,758)
Net increase in policy loans	(17,817)	(16,297)
Net (increase) decrease in short-term investments	(41,128)	(364,781)
Net change in payable or receivable for securities	(43,989)	12,496
Disposition of properties	557	56
Additions to properties	(4,364)	(3,856)
Investment in low-income housing interests	(34,463)	(62,453)
Cash used for investment activities	(388,303)	(408,656)
Cash provided from (used for) financing activities:
Proceeds from exercise of stock options	73,122	138,308
Issue expenses of debt offerings	0	(7,101)
Net borrowings (repayments) of commercial paper	2,840	946
Excess tax benefit from stock option exercises	14,669	14,651
Acquisition of treasury stock	(342,680)	(466,099)
Cash dividends paid to shareholders	(45,487)	(41,293)
Net receipts (withdrawals) from deposit product operations	(16,734)	11,141
Cash provided by (used for) financing activities	(408,320)	(74,447)
Effect of foreign exchange rate changes on cash	2,702	153
Net increase (decrease) in cash	(22,918)	214,718
Cash at beginning of year	61,710	84,113
Cash at end of period	38,792	298,831
7.375% Notes [Member]
Cash provided from (used for) financing activities:
Repayment of Notes	(94,050)	0
3.80% Senior Notes due 2022 [Member]
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	0	150,000
5.875% Junior subordinated debentures due 2052 [Member]
Cash provided from (used for) financing activities:
Proceeds from issuance of debt	$ 0	$ 125,000