Capital Stock, Capital Shares Reserved For Future Issuance, Amount

No definition available.

Name:	arcc_CapitalStockCapitalSharesReservedForFutureIssuanceAmount
Namespace Prefix:	arcc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sale Of Stock, Available For Issuance, Amount

+ References

No definition available.

+ Details

Name:	arcc_SaleOfStockAvailableForIssuanceAmount
Namespace Prefix:	arcc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

+ Details

Name:	srt_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-5

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash received on stock transaction after deduction of issuance costs.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount remaining authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsidiarySaleOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=arcc_A2024ConvertibleNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=arcc_AtTheMarketOfferingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=arcc_OverAllotmentOptionOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

STOCKHOLDERS’ EQUITY - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Number of shares issued (in shares)		65.2	60.5	50.2
Net Proceeds		$ 1,362.7	$ 1,154.3	$ 1,001.3
Authorized amount of stock repurchase program		1,000.0
Stock available for repurchase under the stock repurchase program		1,000.0
2024 Convertible Notes
Subsidiary, Sale of Stock [Line Items]
Conversion price (in usd per share)	$ 20.12
Net Proceeds	$ 407.0
“At the market” offerings
Subsidiary, Sale of Stock [Line Items]
Maximum issuance of common stock		1,000.0
Stock available for issuance		$ 162.0
Number of shares issued (in shares)		65.2	48.4	20.6
Net Proceeds		$ 1,362.7	$ 930.9	$ 417.0
Over-allotment option one
Subsidiary, Sale of Stock [Line Items]
Number of shares issued (in shares)			12.1	11.2
Over-allotment option one \| 2024 Convertible Notes
Subsidiary, Sale of Stock [Line Items]
Number of shares issued (in shares)	20.0