Document and Entity Information - shares	3 Months Ended
	Jun. 30, 2017	Jul. 27, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	CA, INC.
Entity Central Index Key	0000356028
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		421,270,100