Fair Value Measurements and Investments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses) on equity securities held as of the end of the period	$ (102)	$ 172
Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of debt	20,500		$ 22,500
Estimated Fair Value | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of debt	$ 18,400		$ 19,900