Loans and Allowance for Credit Losses - Activity in the Allowance for Credit Losses for Loans Held for Investment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance			$ 97,000,000
Charge-offs	$ (2,000,000)
Provision for credit losses	0	$ 0	26,000,000	$ 10,000,000
Ending balance	119,000,000		119,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	2,000,000	2,000,000	2,000,000
Charge-offs	0	0	0	0
Provision	0	(1,000,000)	(2,000,000)	(1,000,000)
Ending balance	0	1,000,000	0	1,000,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
Beginning balance	0		0
Charge-offs	0		0
Provision	1,000,000		1,000,000
Ending balance	1,000,000		1,000,000
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	80,000,000	69,000,000	73,000,000	61,000,000
Charge-offs	(2,000,000)	0	(13,000,000)	(4,000,000)
Provision for credit losses	(6,000,000)	6,000,000	12,000,000	18,000,000
Ending balance	72,000,000	75,000,000	72,000,000	75,000,000
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,000,000	10,000,000	5,000,000	12,000,000
Charge-offs	0	0	0	0
Provision for credit losses	0	(5,000,000)	(2,000,000)	(7,000,000)
Ending balance	3,000,000	5,000,000	3,000,000	5,000,000
Other Loans | Fund Finance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	2,000,000	4,000,000	2,000,000	4,000,000
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	37,000,000	16,000,000	19,000,000	14,000,000
Charge-offs	0	0	0	0
Provision for credit losses	7,000,000	2,000,000	25,000,000	4,000,000
Ending balance	44,000,000	18,000,000	44,000,000	18,000,000
Off-Balance Sheet Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	15,000,000	17,000,000	23,000,000	19,000,000
Charge-offs	0	0	0	0
Provision for credit losses	(1,000,000)	(2,000,000)	(9,000,000)	(4,000,000)
Ending balance	14,000,000	15,000,000	14,000,000	15,000,000
All Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,000,000	0	(1,000,000)	0
Charge-offs	0	0	0	0
Provision for credit losses	(1,000,000)	0	1,000,000	0
Ending balance	0	0	0	0
Total
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	136,000,000	114,000,000	121,000,000	108,000,000
Charge-offs	(2,000,000)	0	(13,000,000)	(4,000,000)
Provision for credit losses	0	0	26,000,000	10,000,000
Ending balance	$ 134,000,000	$ 114,000,000	$ 134,000,000	$ 114,000,000