Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Income tax expense (benefit) related to continuing operations	$ (294,000,000)	$ 35,000,000	$ (158,000,000)	$ 122,000,000
Tax benefit recognized resulting from goodwill impairment				0
Pretax goodwill impairment charges	0	0	0	570,000,000
Discrete tax benefit recognized	28,000,000	$ 42,000,000
Unrecognized tax benefits	985,000,000		985,000,000
Unrecognized tax benefits that would reduce income tax expense and the effective tax rate	812,000,000		812,000,000
Decrease in unrecognized tax benefits	91,000,000
Possible decrease in unrecognized tax benefits during the next twelve months	$ 60,000,000		$ 60,000,000
European Pharmaceutical Solutions
Segment Reporting Information [Line Items]
Pretax goodwill impairment charges				$ 570,000,000