Stockholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended	32 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Apr. 29, 2015	Apr. 29, 2013
Stockholders Equity Note [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Value			$ 500.0	$ 500.0
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	$ 301.3	$ 301.3
Stock Repurchased and Retired During Period, Shares	8,900,000	40,200,000
Stock Repurchased During Period, Value	$ 188.7	$ 698.7
Document Period End Date	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	807,949
Chief Executive Officer [Member]
Stockholders Equity Note [Line Items]
Stock Repurchased and Retired During Period, Shares	1,000,000
Stock Repurchased During Period, Value	$ 21.4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	800,000
Stock Option, Net-settled share equivalent	350,351
Chief Executive Officer [Member] | Common Stock [Member]
Stockholders Equity Note [Line Items]
Stock Repurchased and Retired During Period, Shares	649,649