Stockholders' Deficit Stockholders' (Deficit) Equity (Summary of Common Stock Repurchase) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended		12 Months Ended
	Feb. 11, 2021	Feb. 06, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Stock Repurchase Program, Authorized Amount	$ 1,000,000	$ 1,000,000
Additional share repurchase amount authorized	$ 747,000	$ 743,000
Treasury Stock Shares Repurchased			3,674	3,911	4,352
Treasury Stock Shares Repurchased For Tax Withholdings And Other			204	243	309
Treasury Stock, Shares, Acquired			3,878	4,154	4,661
Treasury Stock Shares Repurchased, Average Cost Per Share			$ 200.06	$ 188.84	$ 137.86
Treasury stock shares repurchased for tax withholdings and other, average cost per share			208.92	181.07	123.62
Treasury Stock Acquired, Average Cost Per Share			$ 200.48	$ 188.39	$ 136.91
Payments for Repurchase of Common Stock			$ 777,454	$ 782,583	$ 638,152