Stockholders Equity - Narrative (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Nov. 03, 2021	Sep. 30, 2021	Sep. 30, 2020
Stockholders Equity [Line Items]
Stock repurchase program, authorized amount		$ 4,000
Shares repurchased		$ 250	$ 270
Class A and Class B Common Stock
Stockholders Equity [Line Items]
Shares repurchased		7.0
Shares repurchased		$ 250
Remaining buyback authorization amount		$ 2,150
Class A and Class B Common Stock | Subsequent Event
Stockholders Equity [Line Items]
Shares repurchased	1.2
Shares repurchased	$ 50
Class A Common Stock
Stockholders Equity [Line Items]
Cash dividend per share (in dollars per share)		$ 0.24	$ 0.23
Class A Common Stock | Semi Annual Dividend
Stockholders Equity [Line Items]
Cash dividend per share (in dollars per share)		0.24
Class B Common Stock
Stockholders Equity [Line Items]
Cash dividend per share (in dollars per share)		0.24	$ 0.23
Class B Common Stock | Semi Annual Dividend
Stockholders Equity [Line Items]
Cash dividend per share (in dollars per share)		$ 0.24