Loans and Allowance for Credit Losses - Activity in the Allowance for Credit Losses for Loans Held for Investment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,000,000
Provision for credit losses	46,000,000	$ 20,000,000	$ (33,000,000)
Ending balance	135,000,000	97,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
AFS allowance, beginning balance	2,000,000	2,000,000
AFS, charge-offs	0	0
AFS, provision	(2,000,000)	0
AFS allowance, ending balance	0	2,000,000	2,000,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
HTM, allowance beginning balance	0	0
HTM, charge-offs	0	0
HTM, provision	1,000,000	0
HTM, allowance, ending balance	1,000,000	0	0
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	73,000,000	61,000,000
Charge-offs	(17,000,000)	(6,000,000)
Provision for credit losses	16,000,000	18,000,000
Ending balance	72,000,000	73,000,000	61,000,000
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	5,000,000	12,000,000
Charge-offs	0	0
Provision for credit losses	(1,000,000)	(7,000,000)
Ending balance	4,000,000	5,000,000	12,000,000
Other Loans | Fund Finance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,000,000
Ending balance	3,000,000	3,000,000
Other Loans | Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,000,000
Ending balance	1,000,000	2,000,000
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	19,000,000	14,000,000
Charge-offs	0	0
Provision for credit losses	41,000,000	5,000,000
Ending balance	60,000,000	19,000,000	14,000,000
Off-Balance Sheet Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	23,000,000	19,000,000
Charge-offs	0	0
Provision for credit losses	(9,000,000)	4,000,000
Ending balance	14,000,000	23,000,000	19,000,000
All Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(1,000,000)	0
Charge-offs	0	(1,000,000)
Provision for credit losses	0	0
Ending balance	(1,000,000)	(1,000,000)	0
Total Credit Reserve
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	121,000,000	108,000,000
Charge-offs	(17,000,000)	(7,000,000)
Provision for credit losses	46,000,000	20,000,000
Ending balance	$ 150,000,000	$ 121,000,000	$ 108,000,000