Share Repurchase Program (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands				2 Months Ended	12 Months Ended		122 Months Ended
	Feb. 10, 2021	Oct. 28, 2020	Feb. 05, 2020	Feb. 26, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 26, 2021
Share Repurchase Program
Increase in authorized amount		$ 1,000,000	$ 1,000,000
Authorization effective period		3 years	3 years
Remaining balance under share repurchase program					$ 481,500
Common stock repurchased, shares					4,832	3,877
Common stock repurchased, average price per share					$ 431.93	$ 369.55
Common stock repurchased, value					$ 2,087,146	$ 1,432,752
Subsequent event [Member]
Share Repurchase Program
Increase in authorized amount	$ 1,000,000
Cumulative authorized amount	$ 15,800,000
Authorization effective period	3 years
Common stock repurchased, shares				1,100			82,100
Common stock repurchased, average price per share				$ 447.49			$ 179.65
Common stock repurchased, value				$ 478,400			$ 14,700,000