Employee Benefits (Multi-Employer Pension Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 01, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense related to multi-employer plans	$ 473.1	$ 426.9	$ 349.2
Employer pension contribution percentage				25.00%
Health and welfare [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of plans	65
Expense related to multi-employer plans	387.5	378.2	345.9
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of plans	37
Expense related to multi-employer plans	85.6	48.7	3.3
Contribution to the multi-employer plan	84.9	45.6	3.3
Central States, Southeast and Southwest Areas Pension Plan [Member] | Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to the multi-employer plan	51.9	27.6	0
Teamster National 401K Savings Plan [Member] | Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to the multi-employer plan	11.0	5.8	0
I.B. of T. Union Local No 710 Pension Fund [Member] | Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to the multi-employer plan	4.1	2.2	0
Central Pennsylvania Teamsters Defined Benefit Plan [Member] | Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to the multi-employer plan	4.5	2.3	0
Road Carriers Local 707 Pension Fund [Member] | Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to the multi-employer plan	$ 2.5	$ 1.2	$ 0
Workforce Subject to Collective Bargaining Arrangements [Member] | Labor Force Concentration Risk [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percentage of labor force	76.00%