Stockholders' Equity - Share Repurchases (Details) - USD ($)	3 Months Ended			9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Nov. 08, 2018	Apr. 03, 2017
Equity [Abstract]
Initial authorization							$ 2,000,000,000.0
Additional authorization						$ 2,000,000,000.0
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased (in shares)	2,353,852	6,220,190	7,359,609	0	15,933,651
Average price per share (in dollars per share)	$ 36.68	$ 40.18	$ 54.35		$ 46.21
Amount	$ 86,000,000	$ 250,000,000	$ 400,000,000		$ 736,000,000
Open market purchases
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased (in shares)	2,353,852	4,414,840	5,510,415
Average price per share (in dollars per share)	$ 36.68	$ 33.96	$ 54.44
Amount	$ 86,000,000	$ 150,000,000	$ 300,000,000
Accelerated stock repurchases
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased (in shares)	0	1,805,350	1,849,194
Average price per share (in dollars per share)	$ 0	$ 55.39	$ 54.08
Amount	$ 0	$ 100,000,000	$ 100,000,000