Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)	$ 292	$ 180	$ (1,531)
Net operating Loss Carryforwards	2,500
Net operating loss attributable to Switzerland	2,100
Net operating loss attributable to U.S. federal	239
Tax credit carry forwards	13
Gross unrecognized tax benefits	636	584	983	$ 417
Amount of unrecognized tax benefits that would affect the effective tax rate	371
Combined amount of accrued interest and penalties related to uncertain tax positions	36	34
Deferred Tax Assets, Valuation Allowance	296	230
Deferred Tax Assets, Gross	2,557	2,401
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		141	$ 1,760
Deferred Tax Assets, Net	2,241	2,002
Decrease in Unrecognized Tax Benefits is Reasonably Possible	6
Deferred Tax Asset, Intra-entity Transfer, Asset Other than Inventory	$ 1,782	$ 1,781
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Percent	27.00%	17.70%	(101.50%)
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	(1.20%)	(2.70%)	(0.10%)
Net operating loss attributable to various acquired companies	$ 328
Acquired IP intra-entity sales [Member]
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)	$ 64
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	(5.90%)	0.00%	0.00%
State [Member]
Income Tax Disclosure [Line Items]
Net operating loss attributable to California	$ 119
Tax credit carry forwards	174
Reduction in Taxes [Member]
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)			$ 80
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			393
Foreign Tax Authority [Member]
Income Tax Disclosure [Line Items]
Cash, Cash Equivalents, and Short-term Investments	2,000
Swiss Federal Tax Administration (FTA) [Member]
Income Tax Disclosure [Line Items]
Deferred Tax Assets, Valuation Allowance			131
Deferred Tax Assets, Net			$ 1,840
Valuation allowance decrease	$ 29