Incentive Stock Plans - Schedule of Assumptions used for Performance Shares (Details) (Performance Shares [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	23.20%	36.90%
Risk-free rate	0.40%	0.40%
Re-issued 2014 Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility			19.70%	[1]
Risk-free rate			0.70%	[1]
Maximum term			2 years 6 months
2014 Performance Shares, as originally issued [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility			22.80%
Risk-free rate			0.80%

[1] Represents assumptions used in the July 2014 valuation of re-issued 2014 performance share units with a remaining term of 2.5 years. The initial fair value of the 2014 awards assumed an expected volatility of 22.8% and a risk-free rate of 0.8%.