Share-Based Payments (Details 4) - Market stock units - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Market stock units activity
Beginning Balance, Unvested, Shares		269,000
Beginning Balance, Weighted Average Grant Date Fair Value		$ 339.89
Shares, Granted	[1]	168,000
Weighted Average Grant Date Fair Value, Granted		$ 328.03	[1]	$ 493.43	$ 395.22
Shares, Vested		(155,000)
Weighted Average Grant Date Fair Value, Vested		$ 244.68
Shares, Forfeited		(52,000)
Weighted Average Grant Date Fair Value, Forfeited		$ 371.62
Ending Balance, Unvested, Shares		230,000		269,000
Ending Balance, Weighted Average Grant Date Fair Value		$ 355.60		$ 339.89

[1] MSUs granted in 2016 include approximately 15,000 and 20,000 MSUs issued in 2016 based upon the attainment of performance criteria set for 2013 and 2012, respectively, in relation to awards granted in those years. The remainder of MSUs granted during 2016 include awards granted in conjunction with our annual awards made in February 2016 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.