Equity (Schedule of stock repurchases) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended				9 Months Ended
	Oct. 31, 2012	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total cash utilized						$ 850.0
2011 repurchase program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares purchased (in shares)	0.5	6.4	[1],[2]	5.9	[1],[2]	15.0	[1],[2]	6.8	[1],[2]
Average price paid per share (in dollars per share)	$ 49.99	$ 61.42	[2],[3]	$ 50.35	[2],[3]	$ 61.42	[2],[3]	$ 50.35	[2],[3]
Total cash utilized	$ 25.6	$ 350.0		$ 295.0		$ 850.0		$ 295.0

[1] The three and nine month periods ended September 30, 2013 and the nine month ended September 30, 2012 include shares received as part of our accelerated share repurchase agreements described in more detail below.

[2] In any period, cash used in financing activities related to common stock repurchased may differ from the comparable change in equity, reflecting timing differences between the recognition of share repurchase transactions and their settlement for cash. As such, in the third quarter of 2012, 0.5 million shares were repurchased for $25.6 million, which settled in October 2012. Excluding these 0.5 million shares, the average price paid per share was $49.99.

[3] Average price paid per share information does not include the accelerated share repurchase transaction as discussed in more detail below.