Consolidated Statements Of Shareholders' Investment (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Beginning Balance	$ 1,925,700	$ 1,771,200	$ 1,620,500
Net income	689,800	530,100	328,000
Total other comprehensive income (loss)	60,300	(14,600)	(10,400)
Cash dividends declared ($0.75 per share, $0.79 per share and $0.83 per share for year 2011, 2012 and 2013 respectively)	(66,400)	(66,900)	(65,600)
Issuance of common stock	134,200	101,300	110,200
Share-based compensation	61,500	52,000	55,400
Purchases of common stock	(738,100)	(458,000)	(295,100)
Tax benefit relating to share-based compensation plans	21,200	10,600	28,200
Ending Balance	2,088,200	1,925,700	1,771,200
Common Stock
Beginning Balance (in shares)	81,697,409	84,543,338	84,973,586
Beginning Balance	20,400	21,200	21,300
Net income	0	0	0
Cash dividends declared ($0.75 per share, $0.79 per share and $0.83 per share for year 2011, 2012 and 2013 respectively)	0	0	0
Issuance of common stock (in shares)	2,298,049	1,889,148	2,257,762
Issuance of common stock	600	400	600
Share-based compensation	0	0	0
Purchases of common stock (in shares)	(6,559,195)	(4,735,077)	(2,688,010)
Purchases of common stock	(1,600)	(1,200)	(700)
Tax benefit relating to share-based compensation plans	0	0	0
Ending Balance (in shares)	77,436,263	81,697,409	84,543,338
Ending Balance	19,400	20,400	21,200
Capital In Excess Of Par Value
Beginning Balance	1,513,300	1,349,800	1,146,400
Net income	0	0	0
Cash dividends declared ($0.75 per share, $0.79 per share and $0.83 per share for year 2011, 2012 and 2013 respectively)	0	0	0
Issuance of common stock	133,600	100,900	109,600
Share-based compensation	61,500	52,000	55,400
Purchases of common stock	0	0	10,200
Tax benefit relating to share-based compensation plans	21,200	10,600	28,200
Ending Balance	1,729,600	1,513,300	1,349,800
Retained Earnings
Beginning Balance	473,200	466,800	509,000
Net income	689,800	530,100	328,000
Cash dividends declared ($0.75 per share, $0.79 per share and $0.83 per share for year 2011, 2012 and 2013 respectively)	(66,400)	(66,900)	(65,600)
Issuance of common stock	0	0	0
Share-based compensation	0	0	0
Purchases of common stock	(736,500)	(456,800)	(304,600)
Tax benefit relating to share-based compensation plans	0	0	0
Ending Balance	360,100	473,200	466,800
Accumulated Other Comp. (Loss) Inc.
Beginning Balance	(81,200)	(66,600)	(56,200)
Net income	0	0	0
Total other comprehensive income (loss)	60,300	(14,600)	(10,400)
Cash dividends declared ($0.75 per share, $0.79 per share and $0.83 per share for year 2011, 2012 and 2013 respectively)	0	0	0
Issuance of common stock	0	0	0
Share-based compensation	0	0	0
Purchases of common stock	0	0	0
Tax benefit relating to share-based compensation plans	0	0	0
Ending Balance	$ (20,900)	$ (81,200)	$ (66,600)