Employee Stock-Based Compensation (PSU and RSU Rollforward) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
RSU
Number of Shares
Outstanding, beginning of period (in shares)	3,456	3,046	3,643
Vested (in shares)	(1,200)	(1,143)	(1,463)
Forfeited (in shares)	(631)	(438)	(205)
Outstanding, end of period (in shares)	3,478	3,456	3,046
Weighted-Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share)	$ 66	$ 68	$ 45
Vested (in dollars per share)	58
Forfeited (in dollars per share)	73
Outstanding, end of period (in dollars per share)	$ 65	$ 66	$ 68
Aggregate Fair Value
Aggregate Fair Value, Vested	$ 92,340	$ 85,152	$ 133,977
Granted—RSUs
Number of Shares
Granted (in shares)	1,396	1,584	868
Weighted-Average Grant Date Fair Value
Granted (in dollars per share)	$ 59	$ 53	$ 103
Granted—PSUs
Number of Shares
Granted (in shares)	457	407	203
Outstanding, end of period (in shares)	700
Weighted-Average Grant Date Fair Value
Granted (in dollars per share)	$ 67	$ 69	$ 124