Other Assets - Schedule of Other Assets (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Assets [Abstract]
Property and equipment at cost	$ 2,207	$ 2,153
Accumulated depreciation	(935)	(871)
Net property and equipment	1,272	1,282
Proportional amortization investments	1,997	1,866
Net deferred tax assets	1,441	1,224
Accrued interest, fees, and rent receivables	936	935
Nonmarketable equity investments	797	886
Goodwill	669	669	$ 822
Equity-method investments	649	651
Restricted cash and cash equivalents	430	87
Restricted cash held for securitization trusts	325	407
Other accounts receivable	177	189
Operating lease right-of-use assets	91	90
Net intangible assets	62	73
Other assets	1,007	1,036
Total other assets	$ 9,853	$ 9,395
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total other assets	Total other assets