Stock-Based Compensation (Weighted Average Assumptions) (Details)	3 Months Ended
	Mar. 31, 2013 years		Mar. 31, 2012 Y
PBRSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%
Risk-free interest rate	0.35%	[1]
Expected volatility	30.59%	[2]
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%		0.00%
Risk-free interest rate	0.90%	[1]	1.00%	[1]
Expected volatility	41.65%	[3]	42.81%	[3]
Expected life	5.5	[4]	5.5	[4]

[1] The risk-free interest rate for the periods within the contractual term of the options is based on the U.S. Treasury yield curve in effect at the time of the grant.

[2] The expected volatility and average total shareholder return is a measure of the amount by which a stock price has fluctuated or is expected to fluctuate based primarily on our and our peers' historical data.

[3] The expected volatility is a measure of the amount by which a stock price has fluctuated or is expected to fluctuate based primarily on our and our peers' historical data.

[4] The expected life is the period of time, on average, that participants are expected to hold their options before exercise based primarily on our historical data.