Accumulated Stockholders' Equity (Deficit) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	1 Months Ended	7 Months Ended	0 Months Ended	3 Months Ended	4 Months Ended
	Jun. 30, 2013 Share Repurchase Program	Aug. 31, 2012 2012 Share Repurchase Program	Mar. 04, 2013 2012 Share Repurchase Program	Mar. 05, 2013 2013 Share Repurchase Program	Jun. 30, 2013 2013 Share Repurchase Program	Jun. 30, 2013 2013 Share Repurchase Program
Share repurchase program
Amount of shares authorized to be repurchased		$ 300.0		$ 700.0
Term of share repurchase program				2 years
Common stock shares repurchased and retired (in shares)	15.1		10.4		3.1	4.7
Amount used to fund repurchase and retirement of common stock	$ 407.2		$ 266.4		$ 93.8	$ 140.8