Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash paid for:
Interest	$ 91	$ 52
Taxes on income, net of refunds	72	25
Non-cash activities, Investing:
Capital expenditures in accounts payable and accrued expenses	3	28
Capital expenditures through capital lease obligations	109	22
Assets acquired under long-term financing	236	67
Non-cash activities, Financing:
Dividends declared but not yet paid	52	19
Stock issued for the acquisition of HPES	$ 9,850	$ 0