Earnings Per Share (Computation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator (basic and diluted):
Net income		$ 391,293	$ 366,151	$ 1,066,126	$ 1,024,130
Denominator:
Weighted-average common shares outstanding - basic		76,172	80,593	77,415	81,939
Effect of stock options	[1]	797	817	805	902
Weighted-average common shares outstanding - assuming dilution		76,969	81,410	78,220	82,841
Earnings per share - basic		$ 5.14	$ 4.54	$ 13.77	$ 12.50
Earnings per share - assuming dilution		$ 5.08	$ 4.50	$ 13.63	$ 12.36
Antidilutive stock options	[1]	207	650	214	232
Weighted-average exercise price	[1]	$ 360.80	$ 264.65	$ 360.36	$ 268.22

[1] See Note 8 for further information concerning the terms of the Company’s share-based compensation plans.