Income Taxes	9 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's effective tax rate ("ETR") was 44.2% and 29.1% for the three months ended December 31, 2020 and December 31, 2019, respectively, and 54.5% and (11.5)% for the nine months ended December 31, 2020 and December 31, 2019, respectively. For the three and nine months ended December 31, 2020, the primary drivers of the ETR were the gain on sale of HHS Business, global mix of income and foreign tax credits. For the three months ended December 31, 2019, the primary drivers of the ETR were the impact of previously unrecognized tax effects on the tax deductible goodwill impaired during the fiscal 2020 second quarter, the global mix of income, an increase in prior year U.S. federal research and development income tax credits, and an increase in unrecognized tax benefits primarily related to audit activity. For the nine months ended December 31, 2019, the primary drivers of the ETR were the impact of the non-deductible goodwill impairment charge, the non-taxable gain on the arbitration award, the global mix of income, an increase in unrecognized tax benefits primarily related to audit activity, and an increase in prior year U.S. federal research and development income tax credits, net. The majority of unremitted foreign earnings have been taxed in the U.S. We expect a significant portion of the unremitted earnings of our foreign subsidiaries will no longer be subject to U.S. federal income tax upon repatriation to the U.S. However, a portion of these earnings may still be subject to foreign and U.S. state tax consequences when remitted. Earnings in India are indefinitely reinvested. Other foreign earnings are not indefinitely reinvested except for approximately $547 million that could be taxable when repatriated to the U.S. under Treasury regulations that were issued during the first quarter of fiscal 2020. In connection with the HPES Merger, the Company entered into a tax matters agreement with HPE. HPE generally will be responsible for pre-HPES Merger tax liabilities including adjustments made by tax authorities to HPES U.S. and non-U.S. income tax returns. Likewise, DXC is liable to HPE for income tax receivables and refunds which it receives related to pre-HPES Merger periods. Pursuant to the tax matters agreement, the Company recorded a net payable of $3 million due to $48 million of tax indemnification receivable related to uncertain tax positions net of related deferred tax benefits, $79 million of tax indemnification receivable related to other tax payables and $130 million of tax indemnification payable related to other tax receivables. In connection with the USPS Separation, the Company entered into a tax matters agreement with Perspecta. Pursuant to the tax matters agreement, the Company generally will be responsible for tax liabilities arising prior to the USPS Separation. Income tax liabilities transferred to Perspecta primarily relate to pre-HPES Merger periods, for which the Company is indemnified by HPE pursuant to the tax matters agreement between the Company and HPE. The Company remains liable to HPE for tax receivables and refunds which it receives from Perspecta related to pre-HPES Merger periods that were transferred to Perspecta. Pursuant to the tax matters agreement, the Company has recorded a tax indemnification receivable from Perspecta of $81 million and a tax indemnification payable to Perspecta of $44 million related to income tax and other tax liabilities. The IRS is examining the Company's federal income tax returns for fiscal 2008 through the tax year ended October 31, 2018. With respect to CSC's fiscal 2008 through 2017 federal tax returns, the Company has entered into negotiations for a resolution on the years under audit through settlement with the IRS Office of Appeals. The IRS examined several issues for these years that resulted in various audit adjustments. The Company and the IRS Office of Appeals have an agreement in principle as to some of these adjustments, and we disagree with the IRS’ disallowance of certain losses and deductions resulting from restructuring costs and tax planning strategies in previous years. These matters present a potential federal and state tax cost of $410 million (excluding interest and penalties), in addition to other disagreed issues. We expect two years of these audits (fiscal 2010 and fiscal 2013) to proceed to Tax Court. We believe we will ultimately prevail on the technical merits of these issues. The Company has agreed to extend the statute of limitations for fiscal years 2008 through 2012 through August 31, 2021, and for fiscal year 2013 through March 31, 2021 to provide for IRS completion of their review. The Company has agreed to extend the statute of limitations for fiscal years 2014 through fiscal 2017 through October 31, 2021 to provide for IRS completion of their review. The Company expects to reach a resolution for all years no earlier than the fourth quarter of fiscal 2022 except agreed issues related to fiscal 2008 through 2010 federal tax returns, which are expected to be resolved within twelve months. In addition, the Company may settle certain other tax examinations, have lapses in statutes of limitations, or voluntarily settle income tax positions in negotiated settlements for different amounts than the Company has accrued as uncertain tax positions. In the third quarter of fiscal 2021 the Company’s liability for uncertain tax positions decreased by $13 million (excluding interest and penalties and related tax attributes) primarily due to an audit settlement. The Company may need to accrue and ultimately pay additional amounts for tax positions that previously met a more-likely-than-not standard if such positions are not upheld. Conversely, the Company could settle positions by payment with the tax authorities for amounts lower than those that have been accrued or extinguish a position through less payment than previously estimated. The Company believes that the outcomes that are reasonably possible within the next 12 months may result in a reduction in liability for uncertain tax positions of $37 million, excluding interest, penalties and tax carry-forwards.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.