Debt Instrument, Basis Spread On Variable Rate, Credit Spread Adjustment

No definition available.

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Namespace Prefix:	fsk_
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Period Type:	duration

- Definition

Debt Instrument, Variable Rate, Floor

+ References

No definition available.

+ Details

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Namespace Prefix:	fsk_
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Balance Type:	na
Period Type:	duration

- Definition

Revolving Commitment Outstanding

+ References

No definition available.

+ Details

Name:	fsk_RevolvingCommitmentOutstanding
Namespace Prefix:	fsk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term Loan Outstanding

+ References

No definition available.

+ Details

Name:	fsk_TermLoanOutstanding
Namespace Prefix:	fsk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Balance Type:	na
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

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Balance Type:	na
Period Type:	duration

- Definition

Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section S99
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=6450520&loc=d3e32618-110901

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Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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Period Type:	instant

Financing Arrangements - Outstanding Financing Arrangements (Details) € in Millions, £ in Millions, $ in Millions, $ in Millions, $ in Millions			3 Months Ended	12 Months Ended
	Feb. 23, 2023	Jan. 25, 2023	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2023 EUR (€)	Mar. 31, 2023 CAD ($)	Mar. 31, 2023 GBP (£)	Mar. 31, 2023 AUD ($)	Dec. 31, 2022 EUR (€)	Dec. 31, 2022 CAD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 AUD ($)
Debt Instrument [Line Items]
Amount Outstanding			$ 8,713.0	$ 8,731.0
Amount Available			2,577.0	2,559.0
1.90% Term Loan Outstanding
Debt Instrument [Line Items]
Term loan outstanding			$ 200.0	$ 200.0
1.90% Term Loan Outstanding \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			1.90%	1.90%
2.05% Commitments Outstanding \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			2.05%	2.05%
Revolving Credit Facility \| Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Amount Outstanding									€ 260	$ 32	£ 39	$ 112
Long-term line of credit				$ 12.0
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| United States of America, Dollars
Debt Instrument [Line Items]
Exchange rate				1.07					1.07	1.07	1.07	1.07
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| EUR
Debt Instrument [Line Items]
Exchange rate				1.00					1.00	1.00	1.00	1.00
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| CAD
Debt Instrument [Line Items]
Exchange rate				0.74					0.74	0.74	0.74	0.74
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| GBP
Debt Instrument [Line Items]
Basis spread on variable rate, credit spread adjustment			0.0326%	0.0326%
Exchange rate				1.21					1.21	1.21	1.21	1.21
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| AUD
Debt Instrument [Line Items]
Exchange rate				0.68					0.68	0.68	0.68	0.68
Revolving Credit Facility \| 2.05% Commitments Outstanding
Debt Instrument [Line Items]
Revolving commitment outstanding			$ 85.0	$ 85.0
Line of Credit \| Revolving Credit Facility \| Ambler Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			150.0	131.0
Amount Available			$ 50.0	$ 69.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| Ambler Credit Facility \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			2.15%	2.15%
Line of Credit \| Revolving Credit Facility \| Burholme Prime Brokerage Facility
Debt Instrument [Line Items]
Floor on benchmark rate				0.00%
Line of Credit \| Revolving Credit Facility \| Burholme Prime Brokerage Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.25%
Line of Credit \| Revolving Credit Facility \| CCT Tokyo Funding Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 285.0	$ 285.0
Amount Available			$ 15.0	$ 15.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| CCT Tokyo Funding Credit Facility \| Secured Overnight Financing Rate (SOFR) \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.90%	1.90%
Line of Credit \| Revolving Credit Facility \| CCT Tokyo Funding Credit Facility \| Secured Overnight Financing Rate (SOFR) \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			2.05%	2.05%
Line of Credit \| Revolving Credit Facility \| Darby Creek Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 240.0	$ 242.0
Amount Available			$ 10.0	$ 8.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| Darby Creek Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				1.85%
Line of Credit \| Revolving Credit Facility \| Darby Creek Credit Facility \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.90%		1.85%
Line of Credit \| Revolving Credit Facility \| Dunlap Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 467.0	$ 472.0
Amount Available			$ 33.0	$ 28.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| Dunlap Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				1.85%
Line of Credit \| Revolving Credit Facility \| Dunlap Credit Facility \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.90%		1.85%
Line of Credit \| Revolving Credit Facility \| Meadowbrook Run Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 300.0	$ 244.0
Amount Available			$ 0.0	$ 56.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| Meadowbrook Run Credit Facility \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			2.55%	2.55%
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 2,174.0	$ 2,260.0	€ 242	$ 22	£ 30	$ 79
Amount Available			$ 2,469.0	$ 2,383.0
Floor on benchmark rate			0.00%	0.00%
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| United States of America, Dollars
Debt Instrument [Line Items]
Basis spread on variable rate, credit spread adjustment			0.10%	0.10%
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| EUR
Debt Instrument [Line Items]
Exchange rate			1.09		1.09	1.09	1.09	1.09
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| CAD
Debt Instrument [Line Items]
Exchange rate			0.74		0.74	0.74	0.74	0.74
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| GBP
Debt Instrument [Line Items]
Exchange rate			1.24		1.24	1.24	1.24	1.24
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| AUD
Debt Instrument [Line Items]
Exchange rate			0.67		0.67	0.67	0.67	0.67
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| Secured Overnight Financing Rate (SOFR) \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.75%	1.75%
Line of Credit \| Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| Secured Overnight Financing Rate (SOFR) \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			1.88%	1.88%
Line of Credit \| Prime Brokerage Facility \| Burholme Prime Brokerage Facility
Debt Instrument [Line Items]
Amount Outstanding			$ 0.0	$ 0.0
Amount Available			$ 0.0	$ 0.0
Floor on benchmark rate			0.00%
Line of Credit \| Prime Brokerage Facility \| Burholme Prime Brokerage Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				1.25%
Line of Credit \| Prime Brokerage Facility \| Burholme Prime Brokerage Facility \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			1.35%
Line of Credit \| Standby Letters of Credit \| Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Long-term line of credit			$ 12.0
Unsecured Notes
Debt Instrument [Line Items]
Stated interest rate			3.125%		3.125%	3.125%	3.125%	3.125%
Unsecured Notes \| 4.750% Notes due 2022
Debt Instrument [Line Items]
Stated interest rate				4.75%					4.75%	4.75%	4.75%	4.75%
Unsecured Notes \| 4.625% Notes due 2024
Debt Instrument [Line Items]
Stated interest rate			4.625%	4.625%	4.625%	4.625%	4.625%	4.625%	4.625%	4.625%	4.625%	4.625%
Amount Outstanding			$ 400.0	$ 400.0
Fair value			$ 387.0	$ 388.0
Unsecured Notes \| 1.650% Notes due 2024
Debt Instrument [Line Items]
Stated interest rate			1.65%	1.65%	1.65%	1.65%	1.65%	1.65%	1.65%	1.65%	1.65%	1.65%
Amount Outstanding			$ 500.0	$ 500.0
Fair value			$ 460.0	$ 452.0
Unsecured Notes \| 4.125% Notes due 2025
Debt Instrument [Line Items]
Stated interest rate			4.125%	4.125%	4.125%	4.125%	4.125%	4.125%	4.125%	4.125%	4.125%	4.125%
Amount Outstanding			$ 470.0	$ 470.0
Fair value			$ 445.0	$ 442.0
Unsecured Notes \| 4.250% Notes due 2025
Debt Instrument [Line Items]
Stated interest rate			4.25%	4.25%	4.25%	4.25%	4.25%	4.25%	4.25%	4.25%	4.25%	4.25%
Amount Outstanding			$ 475.0	$ 475.0
Fair value			$ 446.0	$ 446.0
Unsecured Notes \| 8.625% Notes due 2025
Debt Instrument [Line Items]
Stated interest rate			8.625%	8.625%	8.625%	8.625%	8.625%	8.625%	8.625%	8.625%	8.625%	8.625%
Amount Outstanding			$ 250.0	$ 250.0
Fair value			$ 254.0	$ 255.0
Unsecured Notes \| 3.400% Notes due 2026
Debt Instrument [Line Items]
Stated interest rate			3.40%	3.40%	3.40%	3.40%	3.40%	3.40%	3.40%	3.40%	3.40%	3.40%
Amount Outstanding			$ 1,000.0	$ 1,000.0
Fair value			$ 899.0	$ 888.0
Unsecured Notes \| 2.625% Notes due 2027
Debt Instrument [Line Items]
Stated interest rate			2.625%	2.625%	2.625%	2.625%	2.625%	2.625%	2.625%	2.625%	2.625%	2.625%
Amount Outstanding			$ 400.0	$ 400.0
Fair value			$ 337.0	$ 334.0
Unsecured Notes \| 3.250% Notes due 2027
Debt Instrument [Line Items]
Stated interest rate			3.25%	3.25%	3.25%	3.25%	3.25%	3.25%	3.25%	3.25%	3.25%	3.25%
Amount Outstanding			$ 500.0	$ 500.0
Fair value			$ 424.0	$ 421.0
Unsecured Notes \| 3.125% Notes due 2028
Debt Instrument [Line Items]
Stated interest rate			3.125%	3.125%	3.125%	3.125%	3.125%	3.125%	3.125%	3.125%	3.125%	3.125%
Amount Outstanding			$ 750.0	$ 750.0
Fair value			615.0	606.0
Unsecured Notes \| 1.85% Class A-1R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding			$ 281.4
Unsecured Notes \| 1.85% Class A-1R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			1.85%
Unsecured Notes \| 2.25% Class A-2R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding			$ 20.5
Unsecured Notes \| 2.25% Class A-2R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			2.25%
Unsecured Notes \| 2.60% Class B-1R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding			$ 32.4
Unsecured Notes \| 2.60% Class B-1R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			2.60%
Unsecured Notes \| 3.011% Class B-2R Notes Outstanding
Debt Instrument [Line Items]
Stated interest rate			3.011%		3.011%	3.011%	3.011%	3.011%
Amount Outstanding			$ 17.4
Collateralized Loan Obligation \| CLO-1 Notes
Debt Instrument [Line Items]
Amount Outstanding			$ 352.0	$ 352.0
Floor on benchmark rate			0.00%	0.00%
Collateralized Loan Obligation \| CLO-1 Notes \| LIBOR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.85%	1.85%
Collateralized Loan Obligation \| CLO-1 Notes \| LIBOR \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			3.01%	3.01%
Collateralized Loan Obligation \| 1.85% Class A-1R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding				$ 281.4
Collateralized Loan Obligation \| 1.85% Class A-1R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				1.85%
Collateralized Loan Obligation \| 2.25% Class A-2R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding				$ 20.5
Collateralized Loan Obligation \| 2.25% Class A-2R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				2.25%
Collateralized Loan Obligation \| 2.60% Class B-1R Notes Outstanding
Debt Instrument [Line Items]
Amount Outstanding				$ 32.4
Collateralized Loan Obligation \| 2.60% Class B-1R Notes Outstanding \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				2.60%
Collateralized Loan Obligation \| 3.011% Class B-2R Notes Outstanding
Debt Instrument [Line Items]
Stated interest rate				3.011%					3.011%	3.011%	3.011%	3.011%
Amount Outstanding				$ 17.4