Segment Information - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Unearned voluntary protection contract revenues		$ 3,100		$ 3,100
Unearned amounts in voluntary protection contract revenues, recognized	$ 239	$ 228	$ 705	$ 649
Other liabilities [Member]
Segment Reporting Information [Line Items]
Unearned voluntary protection contract revenues	$ 3,300		$ 3,300		$ 3,100	$ 2,900
Accounting Standards Update 2014-09 [Member]
Segment Reporting Information [Line Items]
Percentage of voluntary protection contract revenues	86.00%	85.00%	86.00%	84.00%