Shareholders' Equity - Additional Information (Detail) shares in Thousands, $ in Millions		1 Months Ended	12 Months Ended
	Oct. 31, 2020 USD ($)	Nov. 30, 2023 USD ($) shares	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($) shares	Sep. 30, 2021 USD ($) agreement shares	Nov. 30, 2021 shares	Sep. 24, 2013 shares
Class of Stock [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased							10,000
Stock Repurchase Program, Number of Additional Shares Authorized to be Repurchased						10,000
Other comprehensive income before reclassifications, net of taxes | $			$ (106)	$ 306	$ 383
Accelerated Share Repurchase Program
Class of Stock [Line Items]
Total Shares to be Delivered Under Accelerated Share Repurchase Program				1,953
Stock Repurchase Program, Authorized Amount | $				$ 500	$ 1,250
Number of Transactions | agreement					2
Treasury Stock, Shares, Acquired					4,577
Accelerated Share Repurchase Program | Subsequent Event
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount | $		$ 500
Treasury Stock, Shares, Acquired		1,718
Accelerated Share Repurchase Program, Agreement One
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired					462
Open Market Repurchases
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired					2,066
Treasury Stock
Class of Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method | $				$ 650	$ 1,600
Treasury Stock, Shares, Acquired				2,415	6,643
Treasury Stock | Accelerated Share Repurchase Program
Class of Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method | $				$ 150	$ 1,100
Treasury Stock | Open Market Repurchases
Class of Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method | $					500
Benefit Plans
Class of Stock [Line Items]
Other comprehensive income before reclassifications, net of taxes | $	$ 24		$ (37)	$ 169	$ 187