Stockholders' Equity (Schedule of Treasury Stock) (Details) - USD ($) $ / shares in Units, $ in Millions		9 Months Ended		164 Months Ended
	Jul. 14, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Class of Stock [Line Items]
Shares repurchased		5,332,727	2,770,321	68,100,778
Average purchase price per share		$ 150.02	$ 94.44	$ 82.27
Shares repurchased (in $ millions)		$ 800	$ 261	$ 5,603
Aggregate Board of Directors repurchase authorizations (in $ millions)	$ 1,000	$ 1,000	$ 500	$ 6,866