3. Acquisition of subsidiaries (Tables)
|9 Months Ended|
Sep. 30, 2021
|Business Combination and Asset Acquisition [Abstract]|
|Acquisition of subsidiaries||
Tabular disclosure of a material business combination completed during the period, including background, timing, and recognized assets and liabilities. This table does not include leveraged buyouts.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef