Fair Value - Fair Value Measurements on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions	Dec. 31, 2019	Mar. 31, 2019
Assets:
Money market funds and money market deposit accounts	$ 7	$ 6
Time deposits	256	194
Other debt securities	54	53
Deferred purchase price receivable	120	574
Total assets	437	827
Liabilities:
Contingent consideration	58	41
Total liabilities	58	41
Level 1
Assets:
Money market funds and money market deposit accounts	7	6
Time deposits	256	194
Other debt securities	0	0
Deferred purchase price receivable	0	0
Total assets	263	200
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	0
Other debt securities	51	49
Deferred purchase price receivable	0	0
Total assets	51	49
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	0
Other debt securities	3	4
Deferred purchase price receivable	120	574
Total assets	123	578
Liabilities:
Contingent consideration	58	41
Total liabilities	58	41
Other Debt Obligations | Level 2
Liabilities:
Cost basis	38	38
Unrealized gains	$ 13	$ 11