Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020
Cash paid for:
Interest	$ 168	$ 178
Taxes on income, net of refunds	84	130
Operating:
ROU assets obtained in exchange for lease, net	410	142
Prepaid assets acquired under long-term financing	43	14
Investing:
Capital expenditures in accounts payable and accrued expenses	46	92
Capital expenditures through capital lease obligations	205	380
Assets acquired under long-term financing	10	248
(Decrease) increase in deferred purchase price receivable	(52)	(204)
Contingent consideration	3	0
Financing:
Dividends declared but not yet paid	0	55
Income tax refunds	$ 25	$ 20
Change in lease classification from operating to finance lease			$ 87