Common Shares And Stock-Based Awards Plans (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended			0 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Oct. 12, 2012 2010 Repurchase Program [Member]	Mar. 03, 2010 2010 Repurchase Program [Member]	Jun. 13, 2012 2012 Repurchase Program [Member]	Dec. 31, 2012 2012 Repurchase Program [Member]	Dec. 31, 2012 2002 Plan [Member]	Dec. 31, 2012 Stock Options [Member] Employee Awards [Member]	Dec. 31, 2012 Restricted Shares, Restricted Stock Units And Phantom Stock [Member] Employee Awards [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member] Non-Employee Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of common shares	3,200,000	3,700,000	3,300,000	6,700,000
Repurchase of common shares, authorized amount					$ 100	$ 100
Repurchase of common shares, remaining authorized amount							88.0
Repurchase of common shares, value	$ 47.1	$ 56.3	$ 58.9
Repurchase of common shares, average price per share	$ 14.59	$ 15.13	$ 17.70
Vesting period									4 years	4 years	1 year
Contractual life of options								10 years	10 years
Additional shares available for issuance	3,000,000
Number of options, exercisable	3,517,000	3,700,000	3,600,000
Weighted-average exercise price of options exercisable	$ 20.46	$ 20.32	$ 20.40