Share-Based Compensation - Schedule of Data Related to Stock Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value per stock option (in dollars per share)	$ 0	$ 0	$ 0
Aggregate intrinsic value on exercise	$ 77	$ 69	$ 28
Cash received upon exercise	40	93	157
Tax benefits realized related to exercise	16	4	5
Total fair value of stock options vested	0	1	5
Total compensation cost, net of estimated forfeitures, related to unvested stock options not yet recognized, pre-tax	$ 0	$ 0	$ 0
Weighted-average period in years over which stock option compensation cost is expected to be recognized	0 years	0 years	0 years