Stock-Based Compensation (Stock Options Activity) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Options Activity [Roll Forward]
Options outstanding, Beginning	2.9	2.9	2.7
Granted	0.6	0.5	0.6
Exercised	(0.7)	(0.4)	(0.3)
Forfeited	0	(0.1)	(0.1)
Options outstanding, Ending	2.8	2.9	2.9
Stock Options, Weighted Average Exercise Price [Roll Forward]
Options outstanding, Beginning (in usd per share)	$ 35.76	$ 32.32	$ 29.09
Granted (in usd per share)	$ 42.94	$ 40.85	$ 42.47
Exercised (in usd per share)	$ 26.23	$ 17.69	$ 14.88
Forfeited (in usd per share)	$ 40.75	$ 39.69	$ 41.47
Options outstanding, Ending (in usd per share)	$ 39.67	$ 35.76	$ 32.32
Stock Options, Additional Disclosures
Options exercisable	1.5	1.8	1.8
Options exercisable (in usd per share)	$ 38.02	$ 32.91	$ 27.77