Segment Information - Additional Information (Detail) $ in Billions	12 Months Ended
	Mar. 31, 2025 USD ($) Segment	Mar. 31, 2024 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segments | Segment	2
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:BoardOfDirectorsChairmanMember, srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	Segment operating profits (losses) are the primary measure used by the Company's CODM to evaluate segment operating performance. The CODM regularly reviews budget-to-actual variances of segment operating profits (losses) when evaluating segment performance and allocating resources to each segment.
Located outside the United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets located outside the United States	$ 1.7	$ 2.0
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets located outside the United States	$ 1.2	$ 1.3