Commitments- Investment commitments (Details) - CNY (¥) ¥ in Millions	Mar. 31, 2018	Mar. 31, 2017
Business combination and the acquisition of investment securities and equity investees, various arrangements \| Maximum
Investment commitments
Amount committed	¥ 15,174	¥ 17,495

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

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