Share-Based Payments (Details 5) (Market stock units [Member], USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Market stock units [Member]
Market stock units activity
Beginning Balance, Unvested, Shares	398,000
Beginning Balance, Weighted Average Grant Date Fair Value	$ 61.87
Shares, Granted	398,000
Weighted Average Grant Date Fair Value, Granted	$ 74.19	$ 61.87
Shares, Vested	(119,000)
Weighted Average Grant Date Fair Value, Vested	$ 59.89
Shares, Forfeited	(96,000)
Weighted Average Grant Date Fair Value, Forfeited	$ 65.37
Ending Balance, Unvested, Shares	581,000	398,000
Ending Balance, Weighted Average Grant Date Fair Value	$ 69.49	$ 61.87