Effects on net income of amounts reclassified from accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	$ (27)	$ (6)
Unrealized Gains (Losses) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	(17)	(6)
Unrealized Gains (Losses) on Derivative Instruments [Member] | Sales Revenue, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	(19)	(5)
Unrealized Gains (Losses) on Derivative Instruments [Member] | Research And Development [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	2	(1)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	(10)	0
Accumulated Foreign Currency Adjustment Attributable to Parent [Member] | Interest Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	$ (10)	$ 0