Income Taxes - Deferred Tax Liabilities and Assets (Parenthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Unrealized gains or losses included in accumulated other comprehensive income or loss, deferred tax assets	$ 18	$ 16

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses in other comprehensive income.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-8

Name:	us-gaap_DeferredTaxAssetsOtherComprehensiveLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant