Income Taxes (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Apr. 01, 2017
Income Tax Disclosure [Abstract]
Domestic entities				$ 511	$ 454	$ (157)
Entities outside the United States				1,004	850	(17)
Income (loss) from continuing operations, before taxes				$ 1,515	$ 1,304	$ (174)
Income Tax Contingency [Line Items]
Statutory rate				21.00%	31.50%	35.00%
Capital expensing, provisional income tax expense (benefit)	$ (61)				$ (87)
Executive compensation, provisional income tax expense (benefit)					2
Provisional deferred income tax benefit					338
Deferred tax liability, provisional income tax (expense) benefit					338
Provisional income tax expense for transition tax					$ 361
Transition tax, period adjustment, income tax expense (benefit)	(69)	$ 25	$ (44)
Effective income tax rate reconciliation, Tax Cuts and Jobs Act of 2017, transition tax on accumulated foreign earnings, percent				(3.90%)	27.70%
Transition tax, provisional liability				$ 316
Transition tax, income tax liability				324
Transition tax, unrecognized tax benefit receivable				(8)
Undistributed accumulated earnings of foreign subsidiary, withholding taxes					$ 12
Undistributed accumulated earnings of foreign subsidiary, state taxes					7
Undistributed accumulated earnings of foreign subsidiary, period adjustment, income tax expense (benefit)	$ 9
Non-current transition tax included in current provision (benefit)				(44)	332
Interest and penalties for uncertain tax positions included in current provision (benefit)				1	2	$ (9)
Deferred tax liability				1,118	1,044
Deferred tax liabilities, foreign withholding taxes				17
Deferred tax liabilities, state taxes				11
Valuation allowance				1,575	1,440
Net increase (decrease) in deferred tax asset valuation allowance				$ 135
Holiday tax incentives in India
Income Tax Contingency [Line Items]
Additional year of tax holiday extension				2026
Income tax holiday				$ 2	$ 5	$ 1
Income tax holiday (in dollars per share)				$ 0.01	$ 0.02	$ 0.01
Internal Revenue Service
Income Tax Contingency [Line Items]
Liability for uncertain tax positions that if recognized would affect the effective tax rate				$ 138	$ 170	$ 149
Hewlett Packard Enterprise Services
Income Tax Contingency [Line Items]
Accrued income taxes							$ 20
Net uncertain tax positions							49
Other tax payables							133
Other tax receivables							162
Hewlett Packard Enterprise Services | Domestic Tax Authority
Income Tax Contingency [Line Items]
Deferred tax liability							554
India
Income Tax Contingency [Line Items]
Undistributed accumulated earnings of foreign subsidiary, dividend distribution tax					80
Deferred tax liability							$ 46
Currency Translation Adjustment | Luxembourg
Income Tax Contingency [Line Items]
Net increase (decrease) in deferred tax asset valuation allowance				$ (122)
Discontinued Operations | USPS Separation
Income Tax Contingency [Line Items]
Accrued income taxes					24
Income tax receivable					94
Other tax payables					$ 70
Germany
Income Tax Contingency [Line Items]
Net increase (decrease) in deferred tax asset valuation allowance			$ (113)