Stock Repurchase Program (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			63 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Stock Repurchase Program, Period in Force				5 years
Stock Repurchase Program, Authorized Amount				$ 2,000.0
Share repurchase program, shares repurchased				4.8
Share repurchase program, price paid	$ 8.8	$ 7.7	$ 14.1	$ 180.8