Fair Value Measurements and Derivative Instruments - Summary of Changes in Fair Value of Investments Measured Using Level 3 Inputs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 37,895,208	$ 11,891,326	$ 37,895,208	$ 11,891,326	$ 35,002,909	$ 24,598,152	$ 5,856,631	$ 0
Purchases of investments	6,053,461	6,788,833	16,830,559	12,101,791
Proceeds from principal repayments and sales of investments	(2,780,076)	(325,569)	(3,418,044)	(252,272)
Accretion of discount/amortization of premium	40,206	8,842	90,010	12,152
Transfers into Level 3	304,578	118,184	544,781
Transfers out of Level 3	(428,074)	(563,405)	(284,567)
Fair value, end of period	37,895,208	11,891,326	37,895,208	11,891,326
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations	(284,436)	9,133	(450,832)	28,904
Investments, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(13,964)	773	(12,228)	709
Investments, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(283,832)	7,037	(453,453)	28,946
First lien debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	35,623,823	10,874,877	35,623,823	10,874,877	32,556,391	23,046,509	5,346,267	0
Purchases of investments	5,978,812	6,055,199	15,919,276	11,089,353
Proceeds from principal repayments and sales of investments	(2,597,994)	(320,070)	(3,204,195)	(250,267)
Accretion of discount/amortization of premium	39,220	8,651	87,705	11,893
Transfers into Level 3	193,055	90,087	380,165
Transfers out of Level 3	(267,097)	(308,987)	(230,697)
Fair value, end of period	35,623,823	10,874,877	35,623,823	10,874,877
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations	(267,815)	5,042	(364,088)	23,162
Debt Securities, First Lien, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(11,758)	749	(10,188)	694
Debt Securities, First Lien, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(266,806)	2,981	(364,753)	23,204
Second lien debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	1,268,919	646,051	1,268,919	646,051	1,446,075	800,133	453,487	0
Purchases of investments	71,844	422,557	595,997	644,485
Proceeds from principal repayments and sales of investments	(182,082)	(5,499)	(182,080)	(2,005)
Accretion of discount/amortization of premium	933	189	2,191	257
Transfers into Level 3	111,523	28,097	164,614
Transfers out of Level 3	(160,977)	(254,418)	(53,871)
Fair value, end of period	1,268,919	646,051	1,268,919	646,051
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations	(16,191)	1,649	(53,924)	3,299
Debt Securities, Second Lien, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(2,206)	24	(2,184)	15
Debt Securities, Second Lien, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(16,191)	1,614	(55,881)	3,299
Structured Finance Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	287,898	198,108	287,898	198,108	298,409	205,592	0	0
Purchases of investments	0	197,899	122,159	197,899
Proceeds from principal repayments and sales of investments	0	0	0	0
Accretion of discount/amortization of premium	52	2	114	2
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Fair value, end of period	287,898	198,108	287,898	198,108
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations	(10,159)	207	(39,967)	207
Structured Finance, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0	0	0	0
Structured Finance, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(10,563)	207	(39,968)	207
Equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	714,568	172,290	714,568	172,290	$ 702,034	$ 545,918	56,877	0
Purchases of investments	2,805	113,178	193,127	170,054
Proceeds from principal repayments and sales of investments	0	0	(31,769)	0
Accretion of discount/amortization of premium	0	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Fair value, end of period	714,568	172,290	714,568	172,290
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations	9,729	2,235	7,147	2,236
Equity Securities, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0	0	144	0
Equity Securities, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	$ 9,728	2,235	$ 7,148	2,236
Forward Purchase Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period		0		0			$ 0	$ 0
Purchases of investments		0		0
Proceeds from principal repayments and sales of investments		0		(3,709)
Accretion of discount/amortization of premium		0		0
Transfers into Level 3		0
Transfers out of Level 3		0
Fair value, end of period		0		0
Net change in unrealized appreciation (depreciation) included in earnings related to financial instruments, included in net unrealized appreciation (depreciation) on the Consolidated Statements of Operations		0		0
Forward Purchase Obligation, Realized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)		0		3,709
Forward Purchase Obligation, Unrealized Gain (Loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)		$ 0		$ 0