XML 82 R70.htm IDEA: XBRL DOCUMENT v3.8.0.1
Significant Accounting Policies - Additional Information (Detail)
12 Months Ended
Mar. 31, 2018
INR (₨)
Vote
₨ / shares
shares
Mar. 31, 2017
INR (₨)
Vote
shares
Mar. 12, 2018
₨ / shares
Mar. 31, 2016
INR (₨)
shares
Disclosure of classes of share capital [line items]        
Authorized share capital | ₨ ₨ 11,265,000,000      
Par value per share | ₨ / shares     ₨ 2  
Number of vote | Vote 1 1    
Undistributed earnings after taxes not freely available for distribution | ₨ ₨ 1,139,000,000 ₨ 1,139,000,000   ₨ 1,139,000,000
Capital redemption reserve | ₨ 767,000,000 ₨ 80,000,000   ₨ 0
Expected reduction in opening retained earnings on adoption of IFRS 15 | ₨ ₨ 2,239,000,000      
Bottom of range [member]        
Disclosure of classes of share capital [line items]        
Perentage of voting power of another entity 20.00%      
Top of range [member]        
Disclosure of classes of share capital [line items]        
Perentage of voting power of another entity 50.00%      
Treasury shares [member]        
Disclosure of classes of share capital [line items]        
Treasury shares held | shares 23,097,216 13,728,607   14,829,824
Ordinary Shares [member]        
Disclosure of classes of share capital [line items]        
Authorized shares | shares 5,500,000,000      
Par value per share | ₨ / shares ₨ 2      
10.25% Redeemable Cumulative Preference Shares [member]        
Disclosure of classes of share capital [line items]        
Authorized shares | shares 25,000,000      
Par value per share | ₨ / shares ₨ 10      
10% Optionally Convertible Cumulative Preference Shares [member]        
Disclosure of classes of share capital [line items]        
Authorized shares | shares 150,000      
Par value per share | ₨ / shares ₨ 100