Line of Credit Facility, Accordion Feature, Increase Limit

No definition available.

Name:	spgi_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	spgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of Indebtedness To Cash Flow

+ References

No definition available.

+ Details

Name:	spgi_RatioOfIndebtednessToCashFlow
Namespace Prefix:	spgi_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
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

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
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+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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

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

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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+ Details

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

- Details

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

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=spgi_SeniorNotes125Due2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=spgi_A44SeniorNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=spgi_SeniorNotes655Due2037Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=spgi_SeniorNotes45Due2048Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Debt - Narrative (Details) - USD ($)			9 Months Ended
Debt - Narrative (Details) - USD ($)	Apr. 26, 2021	Apr. 25, 2021	Sep. 30, 2021	Dec. 31, 2020	Aug. 13, 2020
Debt Instrument [Line Items]
Long-term debt, fair value			$ 4,400,000,000	$ 4,600,000,000
Indebtedness to cash flow (not greater than)			4
Credit Facility \| Commercial paper
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,500,000,000
Short-term debt			$ 0	$ 0
1.25% Senior Notes due 2030 \| Senior Notes
Debt Instrument [Line Items]
Debt issued					$ 600,000,000
Stated interest rate (as a percent)			1.25%		1.25%
2.3% Senior Notes due 2060 \| Senior Notes
Debt Instrument [Line Items]
Debt issued					$ 700,000,000
Stated interest rate (as a percent)			2.30%		2.30%
4.4% Senior Notes, Due 2026 \| Senior Notes
Debt Instrument [Line Items]
Debt issued			$ 900,000,000
Stated interest rate (as a percent)			4.40%
6.55% Senior Notes due 2037 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)			6.55%
4.5% Senior Notes due 2048 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)			4.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Additional commitments increase for accordion feature			$ 500,000,000
Revolving Credit Facility \| Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,500,000,000
Credit facility, term (in years)	5 years
Commitment fee			0.09%
Revolving Credit Facility \| Previous Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,200,000,000
Credit facility, term (in years)		5 years
Short-term debt		$ 0