Financial Highlights - Schedule Of Financial Highlights (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Investment Company, Financial Highlights [Roll Forward]
Net asset value, beginning of period	$ 24.89	$ 27.17
Results of operation
Net investment income (loss)	0.81	3.05
Net realized gain (loss) and unrealized appreciation (depreciation)	(0.11)	(2.74)
Net increase (decrease) in net assets resulting from operations	0.70	0.31
Stockholder distributions
Distributions from net investment income	(0.70)	(2.66)
Distributions from net realized gain on investments	0	0
Net decrease in net assets resulting from stockholder distributions	(0.70)	(2.66)
Capital share transactions
Repurchases of common stock	0.04	0.07
Net increase (decrease) in net assets resulting from capital share transactions	0.04	0.07
Net asset value, end of period	24.93	24.89
Per share market value, end of period	$ 18.50	$ 17.50
Common stock, shares outstanding (in shares)	280,066,433	281,731,750
Total return based on net asset value	2.97%	1.40%
Total return based on market value	9.72%	(4.61%)
Ratio/Supplemental Data:
Net assets, end of period	$ 6,983	$ 7,012	$ 7,767	$ 7,730
Ratio of net investment income to average net assets	12.94%	11.42%
Ratio of total operating expenses to average net assets	12.83%	10.96%
Ratio of net operating expenses to average net assets	12.83%	10.17%
Portfolio turnover	1.76%	28.61%
Total amount of senior securities outstanding, exclusive of treasury securities	$ 8,713	$ 8,731
Asset coverage per ratio	180.00%	180.00%
4.250% Notes due 2025 | Unsecured Notes
Ratio/Supplemental Data:
Total amount of senior securities outstanding, exclusive of treasury securities	$ 475	$ 475