Investments - Schedule of Loan Exit Fees Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Exit Fees Receivable	$ 40.2	$ 37.5
Included within debt investment cost
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Exit Fees Receivable	35.9	32.5
Deferred receivable related to expired commitments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Exit Fees Receivable	$ 4.3	$ 5.0