Provision for Taxes (Narratives) (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Components of Deferred Tax Assets and Liabilities [Abstract]
Tax adjustment settlements and unusual provisions	$ 366.0	$ 243.0	$ 146.0
NOL to expire, credit	480.0		$ 458.5
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Unrecognized tax benefits, income tax penalties and interest accrued	17.7	$ 15.7
Unrecognized tax benefits, income tax penalties and interest expense	$ 2.0

No definition available.

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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=126928070&loc=d3e28511-109314

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=126928070&loc=d3e28446-109314

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- Definition

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

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- References

No definition available.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

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