Distributions - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended				6 Months Ended
	Aug. 03, 2023 installment $ / shares	Jun. 30, 2023 USD ($) $ / shares	Mar. 31, 2023 $ / shares	Jun. 30, 2022 $ / shares	Mar. 31, 2022 $ / shares	Jun. 30, 2023 USD ($) $ / shares	Jun. 30, 2022 $ / shares	Dec. 31, 2022 USD ($)
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares		$ 0.75	$ 0.70	$ 0.68	$ 0.63	$ 1.45	$ 1.31
Percent of market price						95.00%
Capital loss carryforwards		$ 2,181				$ 2,181
Unrealized appreciation		1,300				1,300		$ 1,349
Unrealized depreciation		2,248				2,248		2,364
Income tax purposes		16,469				16,469		17,159
Net unrealized appreciation (depreciation)		(1,705)				(1,705)		$ (1,782)
Subsidiaries
Schedule of Distributions [Line Items]
Deferred tax liability		8				8
Deferred tax asset		53				53
Deferred tax asset offset by valuation allowance		$ 47				$ 47
Subsequent Event | Regular Quarterly Dividend
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares	$ 0.70
Subsequent Event | Special Distribution
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares	$ 0.15
Number of installments | installment	3
Subsequent Event | To be paid on or about May 31, 2023
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares	$ 0.05
Subsequent Event | To be paid on or about August 30, 2023
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares	0.05
Subsequent Event | To be paid on or about November 29, 2023
Schedule of Distributions [Line Items]
Distributions declared per share (in dollars per share) | $ / shares	$ 0.05