Share-Based Payments (Details 5) (Market stock units, USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Market stock units
Market stock units activity
Beginning Balance, Unvested, Shares	581,000
Beginning Balance, Weighted Average Grant Date Fair Value	$ 69.49
Shares, Granted	319,000	[1]
Weighted Average Grant Date Fair Value, Granted	$ 134.95	[1]	$ 74.19
Shares, Vested	(244,000)
Weighted Average Grant Date Fair Value, Vested	$ 121.40
Shares, Forfeited	(50,000)
Weighted Average Grant Date Fair Value, Forfeited	$ 75.94
Ending Balance, Unvested, Shares	606,000		581,000
Ending Balance, Weighted Average Grant Date Fair Value	$ 94.73		$ 69.49

[1] MSUs granted in 2012 include approximately 39,000 and 42,000 MSUs issued in 2012 based upon the attainment of performance criteria set for 2011 and 2010, respectively, in relation to shares granted in those years. The remainder of MSUs granted during 2012 include awards granted in conjunction with our annual awards made in February 2012 and MSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.