Equity (Narrative) (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Share repurchase program, amount authorized		$ 150,000,000
Treasury stock acquired, shares	4.9	4.6
Treasury stock acquired, value	$ 75,000,000	$ 75,000,000