U.S. and Europe Retrospective Responsibility Plans - Changes in the U.S. Litigation Escrow Account (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Escrow Account [Roll Forward]
Balance at beginning of period	$ 1,449	$ 894
Deposits into the litigation escrow account	350	250
Balance at end of period	1,705	1,144
Interest Income | Opt-out Merchants
Escrow Account [Roll Forward]
Payments to opt-out merchants, net of interest earned on escrow funds	$ (94)	$ 0