Shareholders' Equity (Schedule Of Share Repurchases) (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Apr. 19, 2016	May 06, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Class of Stock [Line Items]
Share repurchase authorization, amount	$ 500.0
Shares repurchased, shares			716,970	0	4,669,213	6,047,437
Cost of shares repurchased			$ 26.2	$ 0.0	$ 166.2	$ 245.3
Shares repurchased, average price per share			$ 36.59	$ 0.00	$ 35.61	$ 40.56
Treasury shares held for issuance pursuant to equity-based compensation plans	3,000,000
Exor SA [Member]
Class of Stock [Line Items]
Shares repurchased, shares		4,053,537
Cost of shares repurchased		$ 164.4
Shares repurchased, average price per share		$ 40.546