Location of Gain (Loss) Recognized in Income on Derivative, Non-Designated Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net revenue	$ 1,387	$ 1,593	$ 1,348	$ 1,209	$ 1,238	$ 1,289	$ 1,286	$ 1,137	$ 5,537	$ 4,950	$ 5,150
Research and development									1,559	1,433	1,320
Other Nonoperating Income (Expense)									63	83	15
Interest And Other Income (Expense), Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net									(4)	25	(26)
Sales Revenue, Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax									71	18	(10)
Research and Development
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax									$ (9)	$ (10)	$ 5