Shareholders' Equity (Schedule Of Share Repurchases) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share repurchases:
Shares repurchased, shares	605,898	0	2,942,085	969,163
Cost of shares repurchased	$ 47,590,000	$ 0	$ 207,048,000	$ 60,000,000
Shares repurchased, average price per share	$ 78.54	$ 0.00	$ 70.37	$ 61.91
Repurchase authorization approved			$ 500,000,000