Cover Page - USD ($) shares in Millions, $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 24, 2020	Jun. 30, 2019
Cover page.
Entity Central Index Key	0000064040
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-1023
Entity Registrant Name	S&P Global Inc.
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	13-1026995
Entity Address, Address Line One	55 Water Street
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10041
City Area Code	212
Local Phone Number	438-1000
Title of 12(b) Security	Common Stock — $1 par value
Trading Symbol	SPGI
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 56.1
Entity Common Stock, Share outstanding		243.8