Revenue Recognition And Accounts Receivable (Summary Of Accounts Receivable And Securitized Accounts Receivable) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 1,559,266	$ 1,445,363
Less allowance for doubtful accounts	21,568	18,925
Accounts receivable, net	1,537,698	1,426,438
Retained Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	923,732	1,445,363
Securitized Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 635,534