Consolidated Statements Of Shareholders' Investment (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Beginning Balance	$ 1,771,200	$ 1,620,500	$ 2,194,900
Net income	530,100	328,000	509,600
Total other comprehensive loss	(14,600)	(10,400)	(31,500)
Cash dividends declared ($0.71 per share, $0.75 per share and $0.79 per share for year 2010, 2011 and 2012 respectively)	(66,900)	(65,600)	(65,900)
Issuance of common stock	101,300	110,200	43,300
Share-based compensation	52,000	55,400	58,100
Purchases of common stock	(458,000)	(295,100)	(1,069,900)
Tax benefit relating to share-based compensation plans	10,600	28,200	7,800
Purchase of noncontrolling interest			(25,900)
Ending Balance	1,925,700	1,771,200	1,620,500
Common Stock
Beginning Balance (in shares)	84,543,338	84,973,586	95,917,095
Beginning Balance	21,200	21,300	24,000
Issuance of common stock (in shares)	1,889,148	2,257,762	1,081,491
Issuance of common stock	400	600	300
Purchases of common stock (in shares)	(4,735,077)	(2,688,010)	(12,025,000)
Purchases of common stock	(1,200)	(700)	(3,000)
Ending Balance (in shares)	81,697,409	84,543,338	84,973,586
Ending Balance	20,400	21,200	21,300
Capital In Excess Of Par Value
Beginning Balance	1,349,800	1,146,400	1,060,900
Issuance of common stock	100,900	109,600	43,000
Share-based compensation	52,000	55,400	58,100
Purchases of common stock		10,200	(10,200)
Tax benefit relating to share-based compensation plans	10,600	28,200	7,800
Purchase of noncontrolling interest			(13,200)
Ending Balance	1,513,300	1,349,800	1,146,400
Retained Earnings
Beginning Balance	466,800	509,000	1,122,400
Net income	530,100	328,000	509,200
Cash dividends declared ($0.71 per share, $0.75 per share and $0.79 per share for year 2010, 2011 and 2012 respectively)	(66,900)	(65,600)	(65,900)
Purchases of common stock	(456,800)	(304,600)	(1,056,700)
Ending Balance	473,200	466,800	509,000
Accumulated Other Comp. (Loss) Inc.
Beginning Balance	(66,600)	(56,200)	(24,700)
Total other comprehensive loss	(14,600)	(10,400)	(31,500)
Ending Balance	(81,200)	(66,600)	(56,200)
Noncontrolling Interest
Beginning Balance			12,300
Net income			400
Purchase of noncontrolling interest			$ (12,700)