Debt and Credit Agreements Debt Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019
Schedule of New Debt Issuance [Line Items]
Repayments of Debt	$ 100.0	$ 200.0	$ 100.0
3.50% Notes Due 2020
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	500.0
3.75% Notes Due 2021
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	500.0
4.65% Notes Due 2028
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	500.0
5.40% Notes Due 2048
Schedule of New Debt Issuance [Line Items]
Debt Instrument, Face Amount	$ 500.0