Earnings Per Share (Changes In Stock Price Impact On Number Of Shares Included In Diluted Earnings Per Share And Issuable Upon Conversion Of Notes) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012
Earning Per Share [Line Items]
Percent of Senior Convertible Notes	1.875%
80.73 [Member]
Earning Per Share [Line Items]
Share Price	80.73
Conversion of stock, shares converted	(3,116)	[1]
Total Treasury Method Incremental Shares	44,670	[2]
80.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	44,670
80.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(47,786)
90.73 [Member]
Earning Per Share [Line Items]
Share Price	90.73
Conversion of stock, shares converted	(20,925)	[1]
Total Treasury Method Incremental Shares	299,912	[2]
90.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	299,912
90.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(320,837)
100.73 [Member]
Earning Per Share [Line Items]
Share Price	100.73
Conversion of stock, shares converted	(35,197)	[1]
Total Treasury Method Incremental Shares	504,477	[2]
100.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	504,477
100.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(539,674)
110.73 [Member]
Earning Per Share [Line Items]
Share Price	110.73
Conversion of stock, shares converted	73,746	[1]
Warrant Shares	120,638
Total Treasury Method Incremental Shares	792,731	[2]
110.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	672,093
110.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(718,985)
120.73 [Member]
Earning Per Share [Line Items]
Share Price	120.73
Conversion of stock, shares converted	263,155	[1]
Warrant Shares	319,805
Total Treasury Method Incremental Shares	1,131,746	[2]
120.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	811,941
120.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(868,591)
130.73 [Member]
Earning Per Share [Line Items]
Share Price	130.73
Conversion of stock, shares converted	423,588	[1]
Warrant Shares	488,502
Total Treasury Method Incremental Shares	1,418,897	[2]
130.73 [Member] | Shares Underlying 1.875% Convertible Notes [Member]
Earning Per Share [Line Items]
Conversion of stock, shares converted	930,395
130.73 [Member] | Shares Due To The Company Under Notes Hedges [Member]
Earning Per Share [Line Items]
Total Treasury Method Incremental Shares	(995,309)

[1] Represents the number of incremental shares to be issued by the Company upon conversion of the 1.875% Convertible Notes, assuming concurrent settlement of the note hedges and warrants.

[2] Represents the number of incremental shares that must be included in the calculation of fully diluted shares under U.S. GAAP.