Long-Term Debt - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended						1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended		12 Months Ended				1 Months Ended						1 Months Ended	12 Months Ended									12 Months Ended			12 Months Ended						3 Months Ended									1 Months Ended	12 Months Ended						1 Months Ended		12 Months Ended
	Oct. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 21, 2012	May 31, 2012	Dec. 31, 2012 ABR-based loans	Sep. 29, 2010 7.00% Senior Unsecured Notes	Dec. 31, 2012 7.00% Senior Unsecured Notes	Jun. 30, 2006 Senior Notes 7.125%	Dec. 31, 2012 Senior Notes 7.125%	Jun. 30, 2008 Senior Notes 7.125%	Dec. 31, 2001 Senior Notes 6.75% Coupon Rate	Dec. 31, 2012 Credit Agreement And Securitization	Dec. 31, 2011 Credit Agreement And Securitization	Dec. 31, 2010 Credit Agreement And Securitization	May 31, 2012 Accounts Receivable Securitization Facility	Dec. 31, 2012 Accounts Receivable Securitization Facility	Oct. 31, 2010 Commercial Paper Rate Plus	Sep. 29, 2010 Debtor Optional Redemption Period 1 7.00% Senior Unsecured Notes	Sep. 29, 2010 Debtor Optional Redemption Period 2 7.00% Senior Unsecured Notes	Sep. 29, 2010 Debtor Optional Redemption Period 3 7.00% Senior Unsecured Notes	Sep. 21, 2012 Amendment of Credit Facility Extended Maturity	Dec. 31, 2012 Revolving Credit Facility	Sep. 21, 2012 Revolving Credit Facility	Dec. 31, 2012 Revolving Credit Facility Eurodollar Based Loans	Dec. 31, 2012 Revolving Credit Facility Minimum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Revolving Credit Facility Minimum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Revolving Credit Facility Maximum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Revolving Credit Facility Maximum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Nov. 15, 2010 Revolving Credit Facility Amendment of Credit Facility	Sep. 21, 2012 Revolving Credit Facility Amendment of Credit Facility Extended Maturity	Dec. 31, 2012 Term Loan A	Dec. 31, 2011 Term Loan A	Sep. 21, 2012 Term Loan A	Dec. 31, 2012 Term Loan A Eurodollar Based Loans	Dec. 31, 2012 Term Loan A Minimum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan A Minimum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan A Maximum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan A Maximum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Sep. 21, 2012 Term Loan A Amendment of Credit Facility Extended Maturity	Sep. 30, 2012 Term Loan B Facility	Dec. 31, 2012 Term Loan B Facility	Sep. 21, 2012 Term Loan B Facility	Dec. 31, 2011 Term Loan B Facility	Dec. 31, 2012 Term Loan B Facility Eurodollar Based Loans	Dec. 31, 2012 Term Loan B Facility Minimum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan B Facility Minimum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan B Facility Maximum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan B Facility Maximum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Sep. 21, 2012 Term Loan- A2	Dec. 31, 2012 Term Loan- A2	Dec. 31, 2012 Term Loan- A2 Eurodollar Based Loans	Dec. 31, 2012 Term Loan- A2 Minimum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan- A2 Minimum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan- A2 Maximum One Month Eurodollar Rate Plus Index Based Loans	Dec. 31, 2012 Term Loan- A2 Maximum One Two Three Six Month Eurodollar Rate Plus Index Based Loans	Sep. 21, 2012 Term Loan- A2 Amendment of Credit Facility	Dec. 31, 2012 Short Term on Demand Credit Facility	Dec. 31, 2012 Term Loan B	Dec. 31, 2011 Term Loan B
Debt Instrument [Line Items]
Line of credit facility, borrowing capacity																															$ 800,000,000																											$ 900,000,000
Line of credit facility, maturity date																							Aug. 15, 2016	Nov. 15, 2015									Nov. 15, 2015																									Aug. 15, 2016
Line of credit facility amount outstanding					3,430,000,000																			164,000,000	800,000,000							777,000,000	983,438,000	1,017,647,000	988,000,000						943,000,000		737,176,000	746,000,000	1,439,500,000						900,000,000	894,375,000							14,000,000
Line of credit facility, extension period of maturity date																							9 months
Line of credit facility, available borrowing capacity																								574,000,000	23,000,000										45,000,000
Proceeds from the new term loan-A2 facility																																																			700,000,000
Current pricing under the new term loan-A2 facility																																																				1.00%
Variable rate basis																																											1.00%
Costs related to extinguishment of debt		29,170,000	0	0																																						29,000,000
Letters of credit, outstanding					125,000,000																			62,000,000
Rate adjustment to weighted average federal funds rate for credit facility borrowings		0.50%
Rate adjustment to one month Eurodollar rate on credit facility borrowings		1.00%
Consolidated leverage ratio																											0.50%	1.50%	1.25%	2.25%							0.50%	1.50%	1.25%	2.25%							1.75%	2.75%	2.00%	3.00%				0.50%	1.50%	1.25%	2.25%
Current applicable margins							0.75%																			1.75%																				2.75%
Current applicable margins																																				0.0175																	0.0175
Quarterly installment payments due in 2013		2,589,000	2,479,000																														72,000,000																			72,000,000
Quarterly installment payments due in 2014		2,012,000																															72,000,000																			72,000,000
Quarterly installment payments due in 2014		68,588,000																															77,000,000																			77,000,000
Quarterly installment payments due in 2016		3,382,793,000																															46,000,000																			46,000,000
Scheduled principal payments																																	42,000,000	26,000,000																		42,000,000								13,000,000	16,000,000
Accounts receivable securitization program credit facility, borrowing capacity	240,000,000					275,000,000
Accounts receivable securitization program credit facility original amount	200,000,000
Accounts receivable securitization program credit facility, maturity date	Oct. 25, 2013								Oct. 01, 2018		Jun. 30, 2016		Nov. 15, 2011
Accounts receivable securitization program, increase in size																	35,000,000
Variable interest rate																			0.475%
Credit facility fee, percentage	0.375%
Commitment percentage for facility fee	102.00%
Accounts receivable securitization program credit facility, amount outstanding		249,000,000
Accounts receivable securitization program, additional capacity																		26,000,000
Senior notes, issued								250,000,000		250,000,000
Interest rate								7.00%		7.125%			6.75%
Treasury rate plus, basis points								50
Unsecured Notes make-whole redemption price																				103.50%	101.75%	100.00%
Senior notes, repayment terms								Payable semiannually in arrears on April 1st and October 1st of each year		Interest on the 7.125% Notes is payable semiannually in arrears on June 30th and December 30th of each year
Line of credit facility additional borrowing capacity												150,000,000
Senior notes, issued													200,000,000
Average amounts outstanding under Credit Agreement, Prior Credit Agreement, demand notes and accounts receivable securitization programs														2,900,000,000	2,900,000,000	610,000,000
Effective interest rate		4.50%	4.60%	5.00%										2.90%	3.40%	3.40%
Maximum amounts outstanding at any month-end														3,060,000,000	3,030,000,000	3,110,000,000
Fair value of debt		$ 3,800,000,000	$ 3,700,000,000