Acquisition of FSKR - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Jun. 16, 2021	Dec. 31, 2021		Dec. 31, 2022	[1]	Jun. 16, 2022	Jun. 14, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Net asset value per share (in dollars per share)		$ 27.17	[1]	$ 24.89				$ 25.02	$ 30.54	$ 31.35	$ 37.20
4.250% Unsecured Notes due 2025 | Senior Debt
Business Acquisition [Line Items]
Stated interest rate						4.25%
Fair value greater than carrying amount	$ 26
FSKR
Business Acquisition [Line Items]
Net asset value per share (in dollars per share)							$ 26.77
Professional fees and other costs						$ 8
Deferred costs and prepaid assets	$ 19
FSKR | FSKR
Business Acquisition [Line Items]
Net asset value per share (in dollars per share)							$ 25.42
FSKR | Common Stock
Business Acquisition [Line Items]
Conversion price right to receive (in shares)	0.9498	0.9498
Equity interest issued or issuable (in shares)	161,374,028	161,374,028

[1] See Note 5 for a discussion of the sources of distributions paid by the Company.