Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Current
Federal	$ (1,859)	$ 1,774	$ 2,756
State	(1)	281	386
Foreign	16	22	11
Total	(1,844)	2,077	3,153
Deferred
Federal	2,100	(1,166)	(2,243)
State	78	(123)	(276)
Foreign	(5)	1	(2)
Total	2,173	(1,288)	(2,521)
Provision for income taxes	$ 329	$ 789	$ 632