Property, Plant and Equipment (Components of Property Plant and Equipment, Specifically Leased Devices) (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Document Period End Date	Sep. 30, 2016
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ (12,196)	$ (9,692)
Property, plant and equipment, net	19,176	20,297
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	6,052	4,913
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(2,293)	(1,267)
Property, plant and equipment, net	$ 3,759	$ 3,646