Income Taxes (Reconciliation of Income Tax Provision) (Details)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Income Tax Expense (Benefit) [Abstract]
Tax at U.S. statutory rate applied to income before income taxes	35.00%		35.00%		35.00%
State income taxes, net of federal tax benefit	1.70%		1.80%		1.80%
Statutory rates other than U.S. statutory rate	(2.80%)		(2.30%)		(3.00%)
Other-net	(2.20%)	[1]	(4.30%)	[1]	(2.90%)	[1]
Effective income tax rate	31.70%		30.20%		30.90%

[1] Other - net is comprised of numerous items, none of which is greater than 1.75 percent of income before income taxes.