Share-based awards - Share-based awards relating to Ant Financial (Details) - CNY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based awards
Share-based compensation expense	¥ 37,491	¥ 20,075	¥ 15,995
Share-based awards relating to Ant Financial
Share-based awards
Share-based compensation expense	¥ 12,855	¥ 2,278	¥ 2,188
Share-based awards relating to Ant Financial \| Share-based awards with four-year vesting schedule
Share-based awards
Vesting period	4 years	4 years	4 years
Vesting percentage per year after initial vesting	25.00%	25.00%	25.00%
Share-based awards relating to Ant Financial \| Share-based awards with four-year vesting schedule and initial vesting at first anniversary
Share-based awards
Vesting period	1 year	1 year	1 year
Vesting percentage	25.00%	25.00%	25.00%
Share-based awards relating to Ant Financial \| Share-based awards with four-year vesting schedule and initial vesting at second anniversary
Share-based awards
Vesting period	2 years	2 years	2 years
Vesting percentage	50.00%	50.00%	50.00%
Share-based awards relating to Ant Financial \| Share-based awards with six-year vesting schedule
Share-based awards
Vesting period	6 years	6 years	6 years

Represents the percentage of stock awards vesting each year after initial vesting.

No definition available.

Name:	baba_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPercentagePerYearAfterInitialVesting
Namespace Prefix:	baba_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Percentage of vesting of share-based compensation awards.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PlanNameAxis=baba_ShareBasedAwardsRelatingToAntFinancialServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=baba_RestrictedStockUnitsWithFourYearVestingScheduleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=baba_RestrictedStockUnitsWithFourYearVestingScheduleAndInitialVestingAtFirstAnniversaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=baba_RestrictedStockUnitsWithFourYearVestingScheduleAndInitialVestingAtSecondAnniversaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=baba_RestrictedStockUnitsWithSixYearVestingScheduleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: