Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Tax credits percentage of qualified maintenance expenditures to reduce federal income tax			50.00%
Tax credits limitation per mile on maintenance expenditures to reduce federal income tax			$ 3,500
Tax benefit from short line tax credit		7,500,000		52,400,000
Effective income tax rate	34.80%	27.90%	35.60%
Provision for income taxes	32,567,000	25,218,000	55,467,000	286,000
Provision for income taxes, other than the retroactive short line tax credit				41,200,000
Provision for income tax as a percentage of income before income taxes other than the retroactive short line tax credits				27.90%
Related to full year 2012 [Member]
Retroactive tax benefit from extension of the short line tax credit				41,000,000
Related to 2013 [Member]
Tax benefit from short line tax credit				11,500,000
RCP&E [Member]
Tax benefit from adjustment to deferred income tax assets			$ 1,000,000