Credit Facility and Other Financing Information (Details 3) (Revolving Credit Facility [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,500,000,000.0
Line of credit facility, expiration date	Mar. 31, 2019
Minimum amount of borrowing capacity before a fixed charge coverage ratio applies	150,000,000
Line of credit, current borrowing capacity based on eligible collateral	1,500,000,000
Current borrowings on credit facility	605,000,000	90,000,000
Letters of credit, outstanding	73,700,000
Line of credit facility, remaining borrowing capacity	$ 821,300,000
Debt Instrument, Covenant Description	The Credit Facility contains common restrictions, including limitations on, among other things, distributions and dividends, acquisitions and investments, indebtedness, liens and affiliate transactions. The Credit Facility requires the maintenance of a minimum fixed charge coverage ratio of one to one if availability under the Credit Facility is less than $150.0. Availability is calculated as the lesser of the Credit Facility commitment or the Company’s eligible collateral after advance rates, less in either case outstanding revolver borrowings and letters of credit. The Company’s obligations under its Credit Facility are secured by its inventory and accounts receivable, and availability under the Credit Facility fluctuates monthly based on the varying levels of eligible collateral.
Line of credit facility, Weighted Average Interest Rate (in hundredths)	2.20%	2.20%