Fair Value - Fair Value Measurements on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Other Debt Securities
Liabilities:
Available-for-sale, cost basis	$ 57	$ 37
Available-for-sale, unrealized loss	(2)
Available-for-sale, unrealized gain		11
Recurring
Assets:
Money market funds and money market deposit accounts	12	156
Time deposits	78	595
Other debt securities	57	51
Deferred purchase price receivable		103
Total assets	147	905
Liabilities:
Contingent consideration	27	46
Total liabilities	27	46
Recurring | Level 1
Assets:
Money market funds and money market deposit accounts	12	156
Time deposits	78	595
Other debt securities	0	0
Deferred purchase price receivable		0
Total assets	90	751
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	55	48
Deferred purchase price receivable		0
Total assets	55	48
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Recurring | Level 2 | Other Income, Net
Liabilities:
Available-for-sale, unrealized gain	17
Recurring | Level 3
Assets:
Money market funds and money market deposit accounts	0	0
Time deposits	0	0
Other debt securities	2	3
Deferred purchase price receivable		103
Total assets	2	106
Liabilities:
Contingent consideration	27	46
Total liabilities	$ 27	$ 46