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Related Party Transactions - Schedule of List of Associates (Parenthetical) (Details) - D W A Nova L L C - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2015
Disclosure Of Significant Investments In Associates [Line Items]      
Voting interest acquired   16.00% 20.00%
Cash consideration     $ 15
Liquidation effective date Nov. 17, 2017    
Impairment loss $ 11 $ 3