XML 145 R134.htm IDEA: XBRL DOCUMENT v3.19.2
Activity in Options Available to be Granted Under Employee Stock Option Scheme (Detail) - Employees Stock Option Scheme - shares
12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options available to be granted, beginning of period 117,841,600 133,673,650 31,534,850
Equity shares allocated for grant under the plan 0.0 0.0 100,000,000.0
Options granted (19,895,000.0) (16,882,050.0) (0.0)
Forfeited/lapsed 3,260,085 1,050,000 2,138,800
Options available to be granted, end of period 101,206,685 117,841,600 133,673,650