Share-Based Payments (Details 5) (Market stock units, USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Assumptions used in valuation of market based stock units
Expected dividend yield	0.00%		0.00%
Minimum range of risk-free interest rates	0.10%		0.20%
Maximum range of risk-free interest rates	0.70%		0.60%
60 calendar day average stock price on grant date minimum	$ 150.33		$ 113.83
60 calendar day average stock price on grant date maximum	$ 240.14		$ 149.79
Weighted average grant date fair value	$ 193.45	[1]	$ 134.95
Minimum
Assumptions used in valuation of market based stock units
Range of expected stock price volatility	21.70%		29.60%
Maximum
Assumptions used in valuation of market based stock units
Range of expected stock price volatility	25.70%		34.00%

[1] MSUs granted in 2013 include approximately 18,000 and 39,000 MSUs issued in 2013 based upon the attainment of performance criteria set for 2012 and 2011, respectively, in relation to shares granted in those years. The remainder of MSUs granted during 2013 include awards granted in conjunction with our annual awards made in February 2013 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.