Per the OIDC Specification:
When supplied as the value for the response_type parameter, a successful response MUST include an Access Token, an Access Token Type, and an id_token. The default Response Mode for this Response Type is the fragment encoding and the query encoding MUST NOT be used. Both successful and error responses SHOULD be returned using the supplied Response Mode, or if none is supplied, using the default Response Mode.
OidcImplicitService and OidcHybridService do not include the id_token in the response if token is also requested.