The plannerPlan resource represents a plan in Office 365. A plan can be owned by a group and contains a collection of plannerTasks. It can also have a collection of plannerBuckets. Each plan object has a details object that can contain more information about the plan. For more information about the relationships between groups, plans, and tasks, see Planner.
Read-only. Date and time at which the plan is created. The Timestamp type represents date and time information using ISO 8601 format and is always in UTC time. For example, midnight UTC on Jan 1, 2014 would look like this: '2014-01-01T00:00:00Z'
Read-only. ID of the plan. It is 28 characters long and case-sensitive. Format validation is done on the service.
ID of the Group that owns the plan. A valid group must exist before this field can be set. After it is set, this property can’t be updated.