Segment Information - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Unearned voluntary protection contract revenues		$ 2,900		$ 2,900
Unearned amounts in voluntary protection contract revenues, recognized	$ 228	$ 198	$ 649	$ 598
Other liabilities [Member]
Segment Reporting Information [Line Items]
Unearned voluntary protection contract revenues	$ 3,100		$ 3,100		$ 2,900	$ 2,700
Accounting Standards Update 2014-09 [Member]
Segment Reporting Information [Line Items]
Percentage of voluntary protection contract revenues	85.00%	83.00%	84.00%	83.00%