Goodwill and Intangible Assets, Net - Intangible Assets Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 431	$ 494	$ 319
Estimated annual amortization expense, 2017	355
Estimated annual amortization expense, 2018	337
Estimated annual amortization expense, 2019	308
Estimated annual amortization expense, 2020	281
Estimated annual amortization expense, 2021	262
Estimated annual amortization expense, after 2021	$ 1,478