Shareholders' Equity Transactions Stock Options Outstanding by Exercise Price (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower Limit	$ 13.37	$ 10.70	$ 10.70
Range of Exercise Price, Upper Limit	$ 47.80	$ 47.80	$ 47.80
Number Outstanding at Year End	4,664,634
Weighted Average Remaining Contractual Life	5 years 9 months 13 days
Weighted Average Exercise Price	$ 26.21	$ 28.99	$ 29.60	$ 29.28
Number Exercisable At Year End	3,074,275
Weighted Average Exercise Price	$ 29.93
Range of Exercise Price 10.70 to 15.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower Limit	$ 13.37
Range of Exercise Price, Upper Limit	$ 15.00
Number Outstanding at Year End	742,186
Weighted Average Remaining Contractual Life	9 years 7 months 13 days
Weighted Average Exercise Price	$ 13.39
Number Exercisable At Year End	1,986
Weighted Average Exercise Price	$ 13.37
Range of Exercise Price 15.01 to 25.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower Limit	$ 15.01
Range of Exercise Price, Upper Limit	$ 25.00
Number Outstanding at Year End	1,774,431
Weighted Average Remaining Contractual Life	6 years 9 months 13 days
Weighted Average Exercise Price	$ 22.50
Number Exercisable At Year End	1,198,832
Weighted Average Exercise Price	$ 22.15
Range of Exercise Price 25.01 to 35.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower Limit	$ 25.01
Range of Exercise Price, Upper Limit	$ 35.00
Number Outstanding at Year End	1,064,676
Weighted Average Remaining Contractual Life	6 years 9 months 13 days
Weighted Average Exercise Price	$ 25.85
Number Exercisable At Year End	790,117
Weighted Average Exercise Price	$ 25.98
Range of Exercise Price 35.01 to 47.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, Lower Limit	$ 35.01
Range of Exercise Price, Upper Limit	$ 47.80
Number Outstanding at Year End	1,083,341
Weighted Average Remaining Contractual Life	1 year 8 months 13 days
Weighted Average Exercise Price	$ 41.45
Number Exercisable At Year End	1,083,340
Weighted Average Exercise Price	$ 41.45