Goodwill and Intangible Assets, Net - Narrative - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 102	$ 108	$ 332	$ 329
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Estimated annual amortization expense, remainder of 2017	78		78
Estimated annual amortization expense, 2018	387		387
Estimated annual amortization expense, 2019	373		373
Estimated annual amortization expense, 2020	358		358
Estimated annual amortization expense, 2021	346		346
Estimated annual amortization expense, thereafter	$ 2,041		$ 2,041