Income Taxes (Details)	3 Months Ended		9 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) county	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) county
Income Tax Contingency [Line Items]
Income tax expense (benefit) related to continuing operations	$ (1,189,000,000)	$ 47,000,000	$ (1,011,000,000)	$ (111,000,000)
Reported income tax expense (benefit) rates (percent)	(16.10%)	16.00%	(16.70%)	(194.70%)
Discrete tax benefit		$ 21,000,000	$ 105,000,000	$ 21,000,000
Number of counties that filed claims | county		2		2
Deferred tax asset for the temporary difference arising from buyer's excess tax basis			105,000,000
Tax benefit recognized for remeasurement of assets and liabilities held-for-sale to fair value				$ 0
Pre-tax impairment charge		$ 282,000,000		282,000,000
Unrecognized tax benefits	$ 1,500,000,000		1,500,000,000
Unrecognized tax benefits that would reduce income tax expense and the effective tax rate	1,400,000,000		1,400,000,000
Increase in unrecognized tax benefits	497,000,000
Possible decrease in unrecognized tax benefits during the next twelve months	93,000,000		93,000,000
National Prescription Opioid Litigation
Income Tax Contingency [Line Items]
Pre-tax expenses related to estimated litigation liability	8,100,000,000		8,100,000,000
After-tax expenses related to estimated litigation liability	$ 6,700,000,000		$ 6,700,000,000
Planned divestiture in Medical-Surgical Solutions business
Income Tax Contingency [Line Items]
Discrete tax benefit		$ 24,000,000		$ 24,000,000