Common Stock Common Stock (Share Repurchase Program) (Details) - USD ($)	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Payments for Repurchase of Common Stock		$ 54,100,000	$ (75,000,000.0)
Payments for Repurchase of Common Stock	$ 54,100,000	$ 54,100,000	$ 75,000,000.0

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration