Face amount or stated value per share of common stock.

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The cash outflow to reacquire common stock during the period.

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The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Authorized share repurchase as a percentage of common stock outstanding.

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Effective tax rate for tax components of other comprehensive income.

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Equity and Other Comprehensive Income (Loss) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Nov. 02, 2018	Sep. 30, 2018	Jul. 01, 2015
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Stock repurchase program, number of shares authorized to be repurchased					40,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01	$ 0.01	$ 0.01
Authorized share repurchase as a percentage of common stock outstanding					15.00%
Stock repurchase program, remaining number of shares authorized to be repurchased	19,100,000
Treasury stock, shares, acquired	2,100,000	0
Purchases of common stock	$ 88.6
Minimum [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Effective Tax Rate, Net of Tax Components of Other Comprehensive Income	25.00%	27.00%
Maximum [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Effective Tax Rate, Net of Tax Components of Other Comprehensive Income	26.00%	28.00%