Share-Based Compensation (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		12 Months Ended
	May 20, 2012	May 19, 2012	Dec. 31, 2013 Stock appreciation rights	Dec. 31, 2012 Stock appreciation rights	Dec. 31, 2011 Stock appreciation rights	Dec. 31, 2010 Stock appreciation rights	Dec. 31, 2013 Stock appreciation rights Maximum	Dec. 31, 2013 Stock appreciation rights Minimum	Dec. 31, 2013 Restricted stock units	Dec. 31, 2012 Restricted stock units	Dec. 31, 2011 Restricted stock units	Dec. 31, 2013 Vests Rateably over 3 Years Stock Options
Share-Based Compensation Arrangement By Share-based Payment Award [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross			500,000	800,000	500,000
Shares reserved for grant		5,000,000
Increase in authorized shares	2,000,000
Granted, Shares			500,000						500,000	600,000	300,000
Vesting period				3 years	3 years	3 years
Award vesting percentage												33.33%
Stock awards expiration							10 years	7 years
Forfeitures percentage			3.00%		3.00%	3.00%
Intrinsic value of SARS exercised			$ 14.9	$ 25.5	$ 8.0
Unrecognized compensation cost			$ 3.2						$ 9.3
Weighted-average remaining contractual term			17						15
Nonvested, balance			2,100,000	2,100,000					1,300,000
Weighted-average grant date fair value			$ 16.63	$ 11.31					$ 18.60
Weighted-average grant date fair value			$ 10.83	$ 6.92	$ 8.12