Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Our effective income tax rate was 16% and 26% for the three months ended September 30, 2018 and 2017, respectively, and 18% and 28% for the nine months ended September 30, 2018 and 2017, respectively. These decreases are primarily due to a reduction of the federal corporate income tax rate from 35% to 21% pursuant to the Tax Cuts and Jobs Act (TCJA), tax benefits from a decrease in uncertain tax positions, an increase in tax credits and an increase in excludable income for state tax purposes. These benefits are partially offset by a decrease in excess tax benefits related to stock based compensation and a one-time qualified production activities deduction for certain software offerings recorded in the prior year. During the nine months ended September 30, 2018, there was a de minimis change in our unrecognized tax benefits. The total amount of gross interest and penalties accrued was immaterial. Our unrecognized tax benefits are expected to change by $1 million during the next 12 months due to lapse of federal and state statute of limitations. We are subject to tax in U.S. federal and various state and local jurisdictions, as well as Canada. We are not subject to any material income tax examinations in federal or state jurisdictions for tax years prior to January 1, 2012. We previously paid Notices of Proposed Assessments disallowing employment tax credits totaling $11 million, plus interest of $4 million in connection with the IRS examination of Gevity HR, Inc. and its subsidiaries, which was acquired by TriNet in June 2009. This issue is being resolved through the litigation process. TriNet and the IRS filed cross motions for summary judgment in this matter in federal district court on February 27, 2018. On September 17, 2018, the district court granted our motion for summary judgment and denied the government’s motion. We are presently working with the IRS to stipulate to a judgment amount in TriNet’s favor, which we expect will be filed some time in November. The IRS will then have 60 days after entry of the judgment to file a notice of appeal of the district court’s decision, should they choose to do so. We will continue to vigorously defend our position through the litigation process, including the appeal, if necessary. We anticipate our recovery of the refund to likely be less than the total amount in dispute.

INCOME TAXES

Our effective income tax rate was 16% and 26% for the three months ended September 30, 2018 and 2017, respectively, and 18% and 28% for the nine months ended September 30, 2018 and 2017, respectively. These decreases are primarily due to a reduction of the federal corporate income tax rate from 35% to 21% pursuant to the Tax Cuts and Jobs Act (TCJA), tax benefits from a decrease in uncertain tax positions, an increase in tax credits and an increase in excludable income for state tax purposes. These benefits are partially offset by a decrease in excess tax benefits related to stock based compensation and a one-time qualified production activities deduction for certain software offerings recorded in the prior year.

During the nine months ended September 30, 2018, there was a de minimis change in our unrecognized tax benefits. The total amount of gross interest and penalties accrued was immaterial. Our unrecognized tax benefits are expected to change by $1 million during the next 12 months due to lapse of federal and state statute of limitations.

We are subject to tax in U.S. federal and various state and local jurisdictions, as well as Canada. We are not subject to any material income tax examinations in federal or state jurisdictions for tax years prior to January 1, 2012. We previously paid Notices of Proposed Assessments disallowing employment tax credits totaling $11 million, plus interest of $4 million in connection with the IRS examination of Gevity HR, Inc. and its subsidiaries, which was acquired by TriNet in June 2009. This issue is being resolved through the litigation process. TriNet and the IRS filed cross motions for summary judgment in this matter in federal district court on February 27, 2018. On September 17, 2018, the district court granted our motion for summary judgment and denied the government’s motion. We are presently working with the IRS to stipulate to a judgment amount in TriNet’s favor, which we expect will be filed some time in November. The IRS will then have 60 days after entry of the judgment to file a notice of appeal of the district court’s decision, should they choose to do so. We will continue to vigorously defend our position through the litigation process, including the appeal, if necessary. We anticipate our recovery of the refund to likely be less than the total amount in dispute.