Share-Based Compensation (RSUs Activity) (Details) - RSUs [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) ₨ / shares	Mar. 31, 2016 USD ($)
Number of RSUs
Outstanding, beginning of period (shares) | shares	4,582,725
Granted (shares) | shares	5,382,251
Exercised (shares) | shares	(1,374,877)
Forteited/Cancelled (shares) | shares	(877,115)
Outstanding, end of period (shares) | shares	7,712,984
Grant Date Fair Value
Outstanding, beginning of period (Indian Rupees per share) | ₨ / shares		₨ 124.52
Granted (Indian Rupees per share) | ₨ / shares		92.20
Exercised (Indian Rupees per share) | ₨ / shares		108.37
Forfeited/Cancelled (Indian Rupees per share) | ₨ / shares		117.18
Outstanding, end of period (Indian Rupees per share) | ₨ / shares		₨ 105.68
Aggregate Intrinsic Value, Outstanding | $	$ 23	₨ 23	$ 7
Aggregate Intrinsic Value, Exercised | $	$ 2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Intrinsic Value | $ / shares	$ 0