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
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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
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-Section S99
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Name:	us-gaap_TreasuryStockValueAcquiredCostMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Stockholders' Equity - Stock Repurchase Program (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Nov. 06, 2018
Class of Stock [Line Items]
Repurchase of common stock (shares)	(1,236,854)	(1,906,308)	(4,175,576)	(4,847,511)
Repurchase of common stock	$ (43.0)	$ (92.1)	$ (147.8)	$ (207.4)
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 261.9		$ 261.9
Common Stock
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 500.0