Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details Textual)

v3.20.2
Stockholders' Equity (Details Textual)
Jan. 31, 2018
USD ($)
Class A and Class B [Member] | 2018 Authorization [Member]  
Equity, Class of Treasury Stock [Line Items]  
Repurchase authorization $ 3,000,000,000.0