Document and Entity Information - $ / shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019	Dec. 31, 2018
Entity Registrant Name	SUNTRUST BANKS INC
Entity Central Index Key	0000750556
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2019
Entity File Number	001-08918
Entity Incorporation, State or Country Code	GA
Entity Tax Identification Number	58-1575035
Entity Address, Address Line One	303 Peachtree Street, N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	(800)
Local Phone Number	786-8787
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
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		443,938,108
Common Stock, Par or Stated Value Per Share	$ 1.00		$ 1.00
NEW YORK STOCK EXCHANGE, INC. [Member]
Title of 12(b) Security	Common Stock
Trading Symbol	STI
Security Exchange Name	NYSE
Preferred Class A [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]
Title of 12(b) Security	Perpetual Preferred Stock, Series A
Trading Symbol	STI PRA
Security Exchange Name	NYSE
Preferred Class B [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]
Title of 12(b) Security	Perpetual Preferred Stock, Series B
Trading Symbol	STI/PRI
Security Exchange Name	NYSE