Financing Arrangement (Line of Credit Facility) (Details) - Revolving Credit Facility [Member] $ in Millions	12 Months Ended
	Mar. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date	Mar. 19, 2015
Line of Credit Facility, Maximum Borrowing Capacity	$ 500
Line of Credit Facility, Expiration Date	Mar. 19, 2020
Option To Request Additional Commitments On Credit Facility	$ 250
Debt Instrument, Fee Amount	$ 2
LineofCreditFacilityTerm1	5 years