Loans and Allowance for Credit Losses - Activity in the Allowance for Credit Losses for Loans Held for Investment (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		$ 97,000,000		$ 97,000,000
Charge-offs	$ (8,000,000)
Provision for credit losses	(18,000,000)		$ 10,000,000	26,000,000	$ 10,000,000
Ending balance	120,000,000			120,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,000,000	2,000,000		2,000,000
Charge-offs	0	0		0
Provision	(2,000,000)	2,000,000		(2,000,000)
Ending balance	0	2,000,000		0
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
Beginning balance		0	2,000,000	0	2,000,000
Charge-offs			0		0
Provision			0		0
Ending balance	0		2,000,000	0	2,000,000
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	82,000,000	73,000,000	61,000,000	73,000,000	61,000,000
Charge-offs	(8,000,000)		(3,000,000)	(11,000,000)	(4,000,000)
Provision for credit losses	6,000,000		11,000,000	18,000,000	12,000,000
Ending balance	80,000,000	82,000,000	69,000,000	80,000,000	69,000,000
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4,000,000	5,000,000	11,000,000	5,000,000	12,000,000
Charge-offs	0		0	0	0
Provision for credit losses	(1,000,000)		(1,000,000)	(2,000,000)	(2,000,000)
Ending balance	3,000,000	4,000,000	10,000,000	3,000,000	10,000,000
Other Loans | Fund Finance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	2,000,000		9,000,000	2,000,000	9,000,000
Other Loans | Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	1,000,000		1,000,000	1,000,000	1,000,000
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	29,000,000	19,000,000	14,000,000	19,000,000	14,000,000
Charge-offs	0		0	0	0
Provision for credit losses	8,000,000		2,000,000	18,000,000	2,000,000
Ending balance	37,000,000	29,000,000	16,000,000	37,000,000	16,000,000
Off-Balance Sheet Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	16,000,000	23,000,000	19,000,000	23,000,000	19,000,000
Charge-offs	0		0	0	0
Provision for credit losses	(1,000,000)		(2,000,000)	(8,000,000)	(2,000,000)
Ending balance	15,000,000	16,000,000	17,000,000	15,000,000	17,000,000
All Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	29,000,000	(1,000,000)	0	(1,000,000)	0
Charge-offs	0		0	0	0
Provision for credit losses	(28,000,000)		0	2,000,000	0
Ending balance	1,000,000	29,000,000	0	1,000,000	0
Total
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	162,000,000	121,000,000	107,000,000	121,000,000	108,000,000
Charge-offs	(8,000,000)		(3,000,000)	(11,000,000)	(4,000,000)
Provision for credit losses	(18,000,000)		10,000,000	26,000,000	10,000,000
Ending balance	$ 136,000,000	$ 162,000,000	$ 114,000,000	$ 136,000,000	$ 114,000,000