Fair Value - Fair Value Measurements on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2018	Mar. 31, 2018
Recurring
Assets:
Money market funds and money market deposit accounts	$ 83	$ 84
Time deposits	80	114
Other debt securities	55	59
Deferred purchase price receivable	207	233
Total assets	425	490
Liabilities:
Contingent consideration	5	5
Total liabilities	5	5
Recurring | Level 1
Assets:
Money market funds and money market deposit accounts	83	84
Time deposits	80	114
Other debt securities	0	0
Deferred purchase price receivable	0	0
Total assets	163	198
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Recurring | Level 2
Assets:
Money market funds and money market deposit accounts	0	0
Time deposits	0	0
Other debt securities	50	53
Deferred purchase price receivable	0	0
Total assets	50	53
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Recurring | Level 3
Assets:
Money market funds and money market deposit accounts	0	0
Time deposits	0	0
Other debt securities	5	6
Deferred purchase price receivable	207	233
Total assets	212	239
Liabilities:
Contingent consideration	5	5
Total liabilities	5	5
Other Debt Obligations
Liabilities:
Cost basis	40	42
Unrealized gains	$ 10	$ 11