Stock-Based Compensation Long-Term Performance Restricted Stock Unit Award Monte Carlo Pricing Model Assumptions (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value	$ 35.09	[1]	$ 35.74	$ 42.51
Long Term Performance Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%		0.00%	0.00%
Expected volatility	30.10%		32.30%	39.10%
Risk-free interest rate	0.70%		0.40%	0.30%
Expected term (years)	2 years 1 month 10 days		2 years 10 days	2 years 6 months 10 days
Weighted-average fair value	$ 33.48		$ 35.15	$ 45.03

[1] Restricted stock units include 14,433 shares for the 2-year award under the 2013 Performance Award Agreement, which are eligible for distribution at December 31, 2014.