Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Assets [Abstract]
Property and equipment at cost	$ 2,425	$ 2,352
Accumulated depreciation	(1,142)	(1,076)
Net property and equipment	1,283	1,276
Investment in qualified affordable housing projects	1,630	1,596
Net deferred tax assets	1,514	1,087
Accrued interest, fees, and rent receivables	898	786
Nonmarketable equity investments	857	842
Goodwill	822	822	$ 822
Equity-method investments	650	608
Restricted cash held for securitization trusts	522	585
Other accounts receivable	181	164
Operating lease right-of-use assets	99	111
Restricted cash and cash equivalents	81	66
Net intangible assets	79	98
Other assets	985	1,097
Total other assets	$ 9,601	$ 9,138
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total other assets	Total other assets