Stockholders' Equity Effect of Escrow Funding on the Company Repurchasing its Common Stock (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Class of Stock [Line Items]
Deposits To Litigation Escrow Account	$ 600	$ 600
Class B common stock
Class of Stock [Line Items]
Number of shares, on an as-coverted basis, that have been repurchased through the Escrow Funding during the period.	5	5
Share Reduction, Price Paid Per Share Escrow Funding	$ 132.32	$ 132.32