Income Taxes - Reconciliation Between Effective Tax Rate On Income From Continuing Operations And Statutory Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Statutory federal income tax rate (percent)	21.00%	21.00%	21.00%
Income (Loss) Attributable to Parent, before Tax [Abstract]
Income tax expense at federal statutory rate	$ 796	$ 972	$ 405
State income taxes, net of federal tax benefit	104	134	85
Tax effect of foreign operations	(16)	(85)	(152)
Foreign-derived intangible income	(67)	(60)	(34)
Unrecognized tax benefits and settlements	116	6	(26)
Opioid-related litigation and claims	0	9	38
Net tax benefit on intellectual property repatriation and sale	(104)	0	0
E.U. disposal transaction loss	4	(8)	345
Valuation allowance release	(157)	0	0
Share-based compensation	(37)	(58)	(10)
Other, net	(10)	(5)	(15)
Income tax expense	629	905	636
Research and development credit	$ 10	$ 4	$ 4

Effective Income Tax Rate Reconciliation, Disposal Transaction Loss, Amount

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Effective Income Tax Rate Reconciliation,Intellectual Property Transfer, Net Tax Benefit

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Effective Income Tax Rate Reconciliation, Litigation and Claims

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of reported income tax benefit from difference to expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to foreign-derived intangible income (FDII).

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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