Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Nov. 08, 2012 Subsequent Event [Member] Repurchase of Equity [Member]
Subsequent Event [Line Items]
Stock repurchased during period, shares					9.9
Stock repurchased during period, value					$ 168.5
Common stock average purchase price					$ 17.03
Stock Repurchased and Retired During Period, Shares	13.9	8.9	21.3	17.5	8.8
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 818.2		$ 649.7