Stockholders' Equity - Narrative (Details)	12 Months Ended
	Mar. 31, 2020 USD ($) vote $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) $ / shares shares	Nov. 08, 2018 USD ($)	Apr. 03, 2017 shares
Equity, Class of Treasury Stock [Line Items]
Common stock, authorized (in shares)	750,000,000	750,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Number of votes per common share | vote	1
Stock repurchase program, shares authorized					2,000,000,000.0
Stock repurchase program, increase (decrease) in authorized shares | $				$ 2,000,000,000.0
Number of shares repurchased (in shares)	15,933,651	19,342,586	1,537,782
Share repurchase amount | $	$ 736,000,000	$ 1,339,000,000	$ 137,000,000
Average price per share (in dollars per share) | $ / shares	$ 46.21	$ 69.20	$ 89.41
Treasury Stock Transactions [Abstract]
Common stock in treasury, at cost (in shares)	2,148,708	1,788,658
Common Stock, $0.01 par value per share | Shares Repurchased From Employees Related To Stock Option Plans
Treasury Stock Transactions [Abstract]
Accepted common stock in lieu of cash in connection with exercise of stock options (in shares)	38,902	42,008	332,558
Accepted common stock in lieu of cash in connection with the tax withholdings associated with the vesting and release of common stock (in shares)	321,148	729,703	684,389
Accelerated Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased (in shares)	3,654,544
Share repurchase amount | $	$ 200,000,000
Average price per share (in dollars per share) | $ / shares	$ 54.73