Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Contingency [Line Items]
Blended tax rate		23.30%	21.40%
U.S. federal statutory rate		21.00%	21.00%	32.00%
Income tax refunds receivable		$ 70
Effective tax rate		7.00%	36.00%	(5.00%)
Deferred tax assets		$ 18	$ 13
Unrecognized tax benefits		39	52	$ 8	$ 8
Decrease for prior-year tax positions		25	0	0
Unrecognized tax benefits decrease		0	2	0
Interest expense, net		8	9	$ 1
Forecast
Income Tax Contingency [Line Items]
Unrecognized tax benefits decrease	$ 5
Federal
Income Tax Contingency [Line Items]
Operating loss carryforwards		260
Net operating loss carryforwards		55
State
Income Tax Contingency [Line Items]
Operating loss carryforwards		28
Other assets
Income Tax Contingency [Line Items]
Deferred tax assets		$ 27	$ 13