Cover - shares	6 Months Ended
	Jun. 30, 2019	Jul. 18, 2019
Document And Entity Information [Abstract]
Title of 12(b) Security	Common stock par value $0.000025 per share
Entity Incorporation, State or Country Code	DE
Entity Registrant Name	TRINET GROUP INC
Trading Symbol	TNET
Entity Central Index Key	0000937098
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	43646
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		69,935,199
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-36373
Entity Tax Identification Number	95-3359658
Entity Address, Address Line One	One Park Place, Suite 600
Entity Address, Postal Zip Code	94568
Entity Address, City or Town	Dublin,
Entity Address, State or Province	CA
City Area Code	510
Local Phone Number	352-5000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Security Exchange Name	NYSE