Income Taxes - Income Tax Related Assets And Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Current assets:
Income tax receivables and prepaid taxes	$ 58.0	$ 113.0
Non-current:
Income taxes receivable and prepaid taxes	180.0	137.0
Deferred tax assets	265.0	355.0
Deferred tax assets, noncurrent	445.0	492.0
Deferred tax assets, total	503.0	605.0
Current liabilities:
Liability for uncertain tax positions	(12.0)	0.0
Income taxes payable	(75.0)	(208.0)
Deferred tax liabilities, current	(87.0)	(208.0)
Non-current:
Deferred taxes	(718.0)	(767.0)
Income taxes payable	(168.0)	(201.0)
Liability for uncertain tax positions	(271.0)	(216.0)
Deferred tax liabilities, noncurrent	(1,157.0)	(1,184.0)
Deferred tax liabilities, total	(1,244.0)	(1,392.0)
Valuation allowance	2,162.0	$ 1,575.0
Net increase (decrease) in deferred tax asset valuation allowance	587.0
Net increase in deferred tax asset valuation allowance for goodwill impairment	637.0
Net decrease in deferred tax asset valuation allowance for releases	(6.0)
Net change in deferred tax asset valuation allowance for currency translation	(44.0)
Singapore
Non-current:
Operating loss carryforward			$ 80.0
Net increase (decrease) in deferred tax asset valuation allowance	$ (47.7)