Document and Entity Information - shares shares in Thousands	6 Months Ended
	Jun. 30, 2015	Aug. 01, 2015
Document and Entity Information
Entity Registrant Name	GREAT WEST LIFE & ANNUITY INSURANCE CO
Entity Central Index Key	0000744455
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		7,032