Share Repurchase Program and Treasury Stock (Details) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Share Repurchase Program and Treasury Stock (Textuals) [Abstract]
Remaining Amount to Repurchase under the program	$ 292,500,000
Stock Repurchase Program, Additional Authorized Amount	750,000,000
Shares Purchased Under Share Repurchase Program	20,800,000
Treasury Stock, Value, Acquired, Cost Method	$ 144,844,000	$ 135,800,000	$ 278,672,000
Number of shares repurchased	680,934	797,095
Average price of share repurchased, per share	$ 212.69	$ 170.31
Exercise of stock options and restricted stock units, shares reissued	216,176	233,146