Stock-Based Compensation And Employee Benefit Plans (Schedule of ESPP Activity) (Details) - Employee Stock [Member] - $ / shares shares in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0.7	0.7	0.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 29.80	$ 29.05	$ 31.88
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP Exercise Price For Shares Issued	74.70	74.70	89.46
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP Exercise Price For Shares Issued	$ 119.37	$ 74.89	$ 107.51