Stock Incentive Plans - Schedule of Stock-Based Compensation (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total share-based compensation cost	$ 74	$ 93	$ 75
Related income tax benefit	15	21	25
Total intrinsic value of options exercised	44	136	73
Tax benefits from exercised stock options and awards	$ 39	$ 84	$ 34

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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