Property, Plant and Equipment (Components of Property Plant and Equipment, Specifically Leased Devices) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Mar. 31, 2015
Property, Plant and Equipment [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ (7,594)	$ (5,358)
Property, plant and equipment, net	21,061	19,721
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	4,432	1,974
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(823)	(197)
Property, plant and equipment, net	$ 3,609	$ 1,777