Share-Based Payments (Details 4) (Market stock units, USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Market stock units
Market stock units activity
Beginning Balance, Unvested, Shares	550,000
Beginning Balance, Weighted Average Grant Date Fair Value	$ 128.04
Shares, Granted	246,000	[1]
Weighted Average Grant Date Fair Value, Granted	$ 395.22	[1]	$ 193.45
Shares, Vested	(363,000)
Weighted Average Grant Date Fair Value, Vested	$ 107.89
Shares, Forfeited	(30,000)
Weighted Average Grant Date Fair Value, Forfeited	$ 192.85
Ending Balance, Unvested, Shares	403,000		550,000
Ending Balance, Weighted Average Grant Date Fair Value	$ 219.29		$ 128.04

[1] MSUs granted in 2014 include approximately 22,000, 27,000, 37,000 and 33,000 MSUs issued in 2014 based upon the attainment of performance criteria set for 2013, 2012, 2011 and 2010, respectively, in relation to awards granted in those years. The remainder of MSUs granted during 2014 include awards granted in conjunction with our annual awards made in February 2014 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.