Property, Plant and Equipment (Components of Property Plant and Equipment, Specifically Leased Devices) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Mar. 31, 2015
Property, Plant and Equipment [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ (8,459)	$ (5,358)
Property, plant and equipment, net	20,645	19,721
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	4,120	1,974
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(799)	(197)
Property, plant and equipment, net	$ 3,321	$ 1,777