Cash Flows (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Cash paid for:
Interest	$ 262	$ 277
Taxes on income, net of refunds	159	202
Operating:
ROU assets obtained in exchange for lease, net	449	314
Prepaid assets acquired under long-term financing	46	23
Investing:
Capital expenditures in accounts payable and accrued expenses	16	121
Capital expenditures through finance lease obligations	277	507
Assets acquired under long-term financing	26	282
(Decrease) increase in deferred purchase price receivable	(52)	58
Contingent consideration	2	19
Financing:
Dividends declared but not yet paid	0	54
Income tax refunds	$ 31	$ 36
Change in lease classification from operating to finance lease			$ 87