Share-Based Payments (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012
Stock Option Activity
Beginning Balance, Outstanding shares	1,691,000
Beginning Balance, Weighted Average Exercise Price	$ 52.75
Shares, Granted	0
Weighted Average Exercise Price, Granted	$ 0.00
Shares, Exercised	(765,000)
Weighted Average Exercise Price, Exercised	$ 50.72
Shares, Cancelled	(19,000)
Weighted Average Exercise Price, Cancelled	$ 51.99
Ending Balance, Outstanding shares	907,000
Ending Balance, Weighted Average Exercise Price	$ 54.48