Fair Value (Narrative) (Details) $ in Millions	Jan. 01, 2016 USD ($) counterparty	Apr. 03, 2015 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, excluding capital leases	$ 1,909	$ 1,635
Accounts receivable with customers involved in bankruptcy proceedings	16
Allowance for doubtful accounts with customers involved in bankruptcy proceedings	10
Other assets with customers in bankruptcy proceedings	1
Accounts payable with customers in bankruptcy proceedings	4
Fixnetix, Limited
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration, range of outcomes, low	0
Contingent consideration, range of outcomes, high	$ 26
Foreign Exchange Contract
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of counterparties to foreign currency derivative instruments \| counterparty	4
Foreign Exchange Contract \| Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative instrument, counterparty risk	$ 8
Total return swaps
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of counterparties to interest rate derivative instruments \| counterparty	1
Total return swaps \| Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative instrument, counterparty risk	$ 6
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, excluding capital leases	1,546	1,550
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, excluding capital leases	$ 1,581	$ 1,681

Accounts Payable with Customers in Bankruptcy Proceedings

No definition available.

Name:	csc_AccountsPayablewithCustomersinBankruptcyProceedings
Namespace Prefix:	csc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Balance of accounts receivable held by the company with customers that are involved in bankruptcy proceedings.

+ References

No definition available.

+ Details

Name:	csc_AccountsReceivableWithCustomersInvolvedInBankruptcyProceedings
Namespace Prefix:	csc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Allowance for doubtful accounts related to accounts receivable held by the company with customers that are involved in bankruptcy proceedings.

+ References

No definition available.

+ Details

Name:	csc_AllowanceForDoubtfulAccountsWithCustomersInvolvedInBankruptcyProceedings
Namespace Prefix:	csc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of counterparties to foreign currency derivative instruments with concentration of credit risk and maximum loss.

+ References

No definition available.

+ Details

Name:	csc_NumberOfCounterpartiesToForeignCurrencyDerivativeInstruments
Namespace Prefix:	csc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Counterparties to Interest Rate Derivative Instruments

+ References

No definition available.

+ Details

Name:	csc_NumberofCounterpartiestoInterestRateDerivativeInstruments
Namespace Prefix:	csc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Other assets with customers in bankruptcy proceedings

+ References

No definition available.

+ Details

Name:	csc_OtherAssetsWithCustomersInBankruptcyProceedings
Namespace Prefix:	csc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

For contingent consideration arrangements and indemnification assets recognized in connection with a business combination, this element represents an estimate of the low-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 15
-Paragraph 83
-URI http://asc.fasb.org/extlink&oid=39740004&loc=d3e34841-113949

+ Details

Name:	us-gaap_FairValueConcentrationOfRiskDerivativeFinancialInstrumentsLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=csc_FixnetixLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: