Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 11, 2019	Jun. 30, 2018	Dec. 31, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	VOYA RETIREMENT INSURANCE & ANNUITY CO
Entity Central Index Key	0000837010
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		55,000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 0
Common stock, par value	$ 50			$ 50
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Company	false