Fair Value Measurements 3 (Details) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Facility exit reserve	$ 7	$ 12	$ 19	$ 49
Facility Exit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Facility exit reserve	7	11	$ 16	$ 21
Facility Exit | Accrued Expenses and Other Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Facility exit reserve	2	3
Facility Exit | Other Noncurrent Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Facility exit reserve	$ 5	$ 8