Share-Based Compensation Plans (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	1 Months Ended			3 Months Ended		3 Months Ended
	Mar. 31, 2012 Y	Apr. 18, 2012 Plan Of 2012 [Member]	Mar. 31, 2012 Plan Of 2012 [Member]	Mar. 31, 2012 Directors' Plan [Member]	Mar. 31, 2012 Performance Restricted Stock Units [Member]	Apr. 18, 2012 Employee Stock Purchase Plan [Member]	Mar. 31, 2012 Minimum [Member] Performance Restricted Stock Units [Member]	Mar. 31, 2012 Maximum [Member] Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of remaining shares that may be issued			2,799,859	49,099
Additional shares authorized		2,750,000				750,000
Number of employee stock purchase programs	2
Reduction in the number of total shares for each stock option or stock appreciation rights granted, per share		1
Reduction in the number of total shares for each award of other share based awards, per share		$ 2.87
Total shareholder return risk-free interest rate	0.41%
Total shareholder return dividend yield	0.85%
Total shareholder return expected life in years	2.83
Awards requisite service period, in years					three
Percentage of target payout of employee varying from actual payout under award							0.00%	200.00%
Unrecognized compensation expenses related to share-based payment arrangements	$ 99.1
Weighted-average period of recognizing unrecognized compensation expenses related to share-based compensation, in years	3