Stockholders' Equity and Earnings per Share (Details ) - USD ($) shares in Millions, $ in Millions	1 Months Ended	9 Months Ended
	Oct. 31, 2014	Jun. 30, 2015	Apr. 30, 2015	May. 31, 2014	Aug. 31, 2013
August 2013 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired		2.9
Stock Repurchase Program Remaining Authorized Amount		$ 315.1
Cash settlements	$ 18.0	33.6
Stock Repurchase Program Authorized Amount					$ 750.0
Treasury Stock Value Acquired Cost Method		$ 260.2
May 2014 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired		4.3
Cash settlements	$ 18.0
Stock Repurchase Program Authorized Amount				$ 650.0
Treasury Stock Value Acquired Cost Method		$ 398.0
Common stock purchased under call options		1.6
April 2015 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired		1.6
Stock Repurchase Program Remaining Authorized Amount		$ 846.1
Cash settlements		14.3
Stock Repurchase Program Authorized Amount			$ 1,000.0
Treasury Stock Value Acquired Cost Method		$ 153.9
Common stock purchased under call options		1.4