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, 2023	Mar. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,000,000
Charge-offs	(3,000,000)
Provision for credit losses	44,000,000	$ 0
Ending balance	115,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,000,000
Charge-offs	0
Provision	0
Ending balance	2,000,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	2,000,000
Charge-offs		0
Provision		0
Ending balance	0	2,000,000
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	73,000,000	61,000,000
Charge-offs	(3,000,000)	(1,000,000)
Provision for credit losses	12,000,000	1,000,000
Ending balance	82,000,000	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)	(1,000,000)
Ending balance	4,000,000	11,000,000
Other Loans | Fund Finance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	3,000,000	10,000,000
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	19,000,000	14,000,000
Charge-offs	0	0
Provision for credit losses	10,000,000	0
Ending balance	29,000,000	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	(7,000,000)	0
Ending balance	16,000,000	19,000,000
All Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(1,000,000)	0
Charge-offs	0	0
Provision for credit losses	30,000,000	0
Ending balance	29,000,000	0
Total
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	121,000,000	108,000,000
Charge-offs	(3,000,000)	(1,000,000)
Provision for credit losses	44,000,000	0
Ending balance	$ 162,000,000	$ 107,000,000