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, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 135,000,000
Provision for credit losses	75,000,000	$ 46,000,000	$ 20,000,000
Ending balance	174,000,000	135,000,000
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
AFS allowance, beginning balance	0	2,000,000
AFS, provision		(2,000,000)
AFS, charge-offs		0
AFS allowance, ending balance	0	0	2,000,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward]
HTM, allowance beginning balance	1,000,000	0
HTM, provision	(1,000,000)	1,000,000
HTM, charge-offs	0	0
HTM, allowance, ending balance	0	1,000,000	0
Leveraged Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	72,000,000	73,000,000
Provision for credit losses	13,000,000	16,000,000
Charge-offs	(17,000,000)	(17,000,000)
Ending balance	68,000,000	72,000,000	73,000,000
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,000,000	4,000,000
Provision for credit losses	1,000,000	(1,000,000)
Charge-offs	0	0
Ending balance	4,000,000	3,000,000	4,000,000
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 | Total Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,000,000
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
Provision for credit losses	67,000,000	41,000,000
Charge-offs	(25,000,000)	0
Ending balance	102,000,000	60,000,000	19,000,000
Off-Balance Sheet Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	14,000,000	23,000,000
Provision for credit losses	(5,000,000)	(9,000,000)
Charge-offs	0	0
Ending balance	9,000,000	14,000,000	23,000,000
Total Credit Reserve
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	150,000,000	121,000,000
Provision for credit losses	75,000,000	46,000,000
Charge-offs	(42,000,000)	(17,000,000)
Ending balance	$ 183,000,000	$ 150,000,000	$ 121,000,000