Nominal or face amount used to calculate payment on derivative.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

Derivatives - Schedule of Derivative Instruments (Details) £ in Millions, $ in Millions	Sep. 30, 2024 GBP (£)	Sep. 30, 2024 USD ($)	Mar. 31, 2024 GBP (£)	Mar. 31, 2024 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount \| £	£ 360.0		£ 728.0
Designated as Hedging Instrument \| Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount \| $		$ 461		$ 919