Share Repurchase Program and Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock Repurchase Program, Additional Authorized Amount					$ 2,000,000
Share Repurchase Program and Treasury Stock (Textuals) [Abstract]
Remaining Amount to Repurchase under the program	$ 1,700,000				$ 1,700,000
Shares Purchased Under Share Repurchase Program	28,100,000				28,100,000
Treasury Stock, Value, Acquired, Cost Method	$ 186,250	$ 186,250	$ 118,749	$ 118,750	$ 372,500	$ 237,500
Number of shares repurchased					(539,326)	(396,218)
Average price of share repurchased, per share					$ 690.66	$ 599.40
Exercise of stock options and restricted stock units, shares reissued					226,595	68,653