Loans and Allowance for Credit Losses - Activity in the Allowance for Credit Losses for Loans Held for Investment (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 135,000,000
Charge-offs	(29,000,000)
Provision for credit losses	27,000,000	$ 44,000,000
Ending balance	135,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	2,000,000
Charge-offs	0	0
Provision	0	0
Ending balance	0	2,000,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,000,000
Charge-offs	0
Provision	0
Ending balance	1,000,000
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	72,000,000	73,000,000
Charge-offs	(6,000,000)	(3,000,000)
Provision for credit losses	5,000,000	12,000,000
Ending balance	71,000,000	82,000,000
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4,000,000	5,000,000
Charge-offs	0	0
Provision for credit losses	1,000,000	(1,000,000)
Ending balance	5,000,000	4,000,000
Other Loans | Fund Finance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	4,000,000	3,000,000
Other Loans | Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	1,000,000	1,000,000
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	60,000,000	19,000,000
Charge-offs	(25,000,000)	0
Provision for credit losses	25,000,000	10,000,000
Ending balance	60,000,000	29,000,000
Off-Balance Sheet Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	14,000,000	23,000,000
Charge-offs	0	0
Provision for credit losses	(4,000,000)	(7,000,000)
Ending balance	10,000,000	16,000,000
All Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(1,000,000)	(1,000,000)
Charge-offs	0	0
Provision for credit losses	0	30,000,000
Ending balance	(1,000,000)	29,000,000
Total
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	150,000,000	121,000,000
Charge-offs	(31,000,000)	(3,000,000)
Provision for credit losses	27,000,000	44,000,000
Ending balance	$ 146,000,000	$ 162,000,000