Income Taxes - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Line Items]
Provision for income taxes at U.S. federal statutory tax rate	35.00%	21.00%	31.60%	35.00%
Income tax benefit attributable to revaluation of net deferred tax liabilities			$ 2,900,000,000
Valuation Allowance		$ 24,000,000	29,000,000
Unremitted earnings in foreign subsidiary		233,000,000	223,000,000
Income Tax Penalties Accrued		0	0	$ 0
Federal [Member]
Income Tax Disclosure [Line Items]
Operating Loss Carryforwards		$ 2,100,000,000	$ 857,000,000
Tax credit carryforward, Expiration Date		Mar. 31, 2028
Expiration Dates			Mar. 31, 2038
State [Member]
Income Tax Disclosure [Line Items]
Operating Loss Carryforwards		$ 147,000,000	$ 109,000,000
Expiration Dates		Mar. 31, 2020