Fair Value Measurements 3 (Details) - USD ($) $ in Millions	Jun. 30, 2018	Mar. 31, 2018
Fair value measurements
Facility exit reserves	$ 100	$ 7
Facility Exit
Fair value measurements
Facility exit reserves	40	7
Facility Exit | Accrued Expenses and Other Current Liabilities
Fair value measurements
Facility exit reserves	13	2
Facility Exit | Other Noncurrent Liabilities
Fair value measurements
Facility exit reserves	$ 27	$ 5