CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Trading assets	$ 1,156	$ 1,270
Available-for-sale securities	9,566	9,885
Other investments	$ 306	$ 292
Common stock, par value per share (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	650,000,000	650,000,000
Common stock, shares issued (in shares)	248,561,711	248,018,564
Common stock, shares outstanding (in shares)	208,498,326	215,122,523
Treasury stock (in shares)	40,063,385	32,896,041
Asset pledged as collateral
Trading assets	$ 980	$ 1,188
Available-for-sale securities	23	74
Other investments	$ 6	$ 14