Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash paid for:
Interest	$ 178	$ 149
Taxes on income, net of refunds	130	74
Operating:
ROU assets obtained in exchange for lease, net	142	0
Prepaid assets acquired under long-term financing	14	0
Investing:
Capital expenditures in accounts payable and accrued expenses	92	28
Capital expenditures through capital lease obligations	380	396
Assets acquired under long-term financing	248	76
(Decrease) / increase in deferred purchase price receivable	(204)	818
Financing:
Dividends declared but not yet paid	55	54
Income tax refunds	20	$ 157
Change in lease classification from operating to finance lease	$ 87