Fair Value - Fair Value Measurements on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions	Dec. 31, 2017	Mar. 31, 2017
Assets:
Money market funds and money market deposit accounts	$ 217	$ 406
Time deposits	35
Foreign bonds	52
Other debt securities	7
Deferred purchase price receivable	249	252
Total assets	560	658
Liabilities:
Contingent consideration	8	7
Total liabilities	8	7
Level 1
Assets:
Money market funds and money market deposit accounts	217	406
Time deposits	35
Foreign bonds	0
Other debt securities	0
Deferred purchase price receivable	0	0
Total assets	252	406
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 2
Assets:
Money market funds and money market deposit accounts	0	0
Time deposits	0
Foreign bonds	52
Other debt securities	0
Deferred purchase price receivable	0	0
Total assets	52	0
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 3
Assets:
Money market funds and money market deposit accounts	0	0
Time deposits	0
Foreign bonds	0
Other debt securities	7
Deferred purchase price receivable	249	252
Total assets	256	252
Liabilities:
Contingent consideration	8	7
Total liabilities	$ 8	$ 7